| 7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline | 7,8-DICHLORO-1,2,3,4-TETRAHYDROISOQUINOLINE may increase the hypoglycemic activities of Sitagliptin. | Experimental |
| Abacavir | The serum concentration of Abacavir can be decreased when it is combined with Sitagliptin. | Approved, Investigational |
| Abiraterone | The serum concentration of Sitagliptin can be increased when it is combined with Abiraterone. | Approved |
| Acetaminophen | The serum concentration of Sitagliptin can be increased when it is combined with Acetaminophen. | Approved |
| Acetohexamide | Sitagliptin may increase the hypoglycemic activities of Acetohexamide. | Withdrawn |
| Acetylsalicylic acid | Acetylsalicylic acid may increase the hypoglycemic activities of Sitagliptin. | Approved, Vet Approved |
| Afatinib | The serum concentration of Sitagliptin can be increased when it is combined with Afatinib. | Approved |
| Albendazole | The serum concentration of Sitagliptin can be increased when it is combined with Albendazole. | Approved, Vet Approved |
| Aldosterone | The serum concentration of Sitagliptin can be decreased when it is combined with Aldosterone. | Experimental |
| Alectinib | The serum concentration of Sitagliptin can be increased when it is combined with Alectinib. | Approved |
| Alfentanil | The serum concentration of Sitagliptin can be increased when it is combined with Alfentanil. | Approved, Illicit |
| Alfuzosin | The serum concentration of Alfuzosin can be increased when it is combined with Sitagliptin. | Approved, Investigational |
| Alprazolam | The serum concentration of Alprazolam can be increased when it is combined with Sitagliptin. | Approved, Illicit, Investigational |
| Amantadine | The serum concentration of Sitagliptin can be increased when it is combined with Amantadine. | Approved |
| Ambroxol acefyllinate | The serum concentration of Ambroxol acefyllinate can be decreased when it is combined with Sitagliptin. | Experimental |
| Amineptine | The serum concentration of Amineptine can be increased when it is combined with Sitagliptin. | Illicit, Withdrawn |
| Aminohippuric acid | The serum concentration of Sitagliptin can be increased when it is combined with Aminohippuric acid. | Approved |
| Aminophylline | The serum concentration of Aminophylline can be decreased when it is combined with Sitagliptin. | Approved |
| Aminosalicylic Acid | Aminosalicylic Acid may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Amiodarone | The metabolism of Sitagliptin can be decreased when combined with Amiodarone. | Approved, Investigational |
| Amitriptyline | The serum concentration of Amitriptyline can be increased when it is combined with Sitagliptin. | Approved |
| Amlodipine | The serum concentration of Sitagliptin can be increased when it is combined with Amlodipine. | Approved |
| Amprenavir | The serum concentration of Sitagliptin can be decreased when it is combined with Amprenavir. | Approved |
| Amsacrine | The serum concentration of Sitagliptin can be increased when it is combined with Amsacrine. | Approved |
| Aprepitant | The serum concentration of Sitagliptin can be increased when it is combined with Aprepitant. | Approved, Investigational |
| Aripiprazole | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Aripiprazole. | Approved, Investigational |
| Arsenic trioxide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Arsenic trioxide. | Approved, Investigational |
| Articaine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Articaine. | Approved |
| Asenapine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Asenapine. | Approved |
| Astemizole | The serum concentration of Sitagliptin can be increased when it is combined with Astemizole. | Approved, Withdrawn |
| Atazanavir | The metabolism of Sitagliptin can be decreased when combined with Atazanavir. | Approved, Investigational |
| Atenolol | The serum concentration of Sitagliptin can be increased when it is combined with Atenolol. | Approved |
| Atomoxetine | The metabolism of Sitagliptin can be decreased when combined with Atomoxetine. | Approved |
| Atorvastatin | The serum concentration of Atorvastatin can be increased when it is combined with Sitagliptin. | Approved |
| Azelastine | The serum concentration of Sitagliptin can be increased when it is combined with Azelastine. | Approved |
| Azithromycin | The serum concentration of Sitagliptin can be increased when it is combined with Azithromycin. | Approved |
| Balsalazide | Balsalazide may increase the hypoglycemic activities of Sitagliptin. | Approved, Investigational |
| Benazepril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Benazepril. | Approved, Investigational |
| Bendroflumethiazide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Bendroflumethiazide. | Approved |
| Benmoxin | Benmoxin may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Benzocaine | The serum concentration of Sitagliptin can be increased when it is combined with Benzocaine. | Approved |
| Bepridil | The serum concentration of Sitagliptin can be increased when it is combined with Bepridil. | Approved, Withdrawn |
| Betamethasone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Betamethasone. | Approved, Vet Approved |
| Bexarotene | The serum concentration of Sitagliptin can be decreased when it is combined with Bexarotene. | Approved, Investigational |
| Biperiden | The serum concentration of Sitagliptin can be increased when it is combined with Biperiden. | Approved |
| Boceprevir | The serum concentration of Sitagliptin can be decreased when it is combined with Boceprevir. | Approved, Investigational |
| Bortezomib | The metabolism of Sitagliptin can be decreased when combined with Bortezomib. | Approved, Investigational |
| Bosentan | The serum concentration of Sitagliptin can be decreased when it is combined with Bosentan. | Approved, Investigational |
| Bosutinib | The serum concentration of Sitagliptin can be increased when it is combined with Bosutinib. | Approved |
| Brexpiprazole | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Brexpiprazole. | Approved |
| Bromocriptine | The serum concentration of Bromocriptine can be increased when it is combined with Sitagliptin. | Approved, Investigational |
| Bumetanide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Bumetanide. | Approved |
| Buprenorphine | The serum concentration of Sitagliptin can be increased when it is combined with Buprenorphine. | Approved, Illicit, Investigational, Vet Approved |
| Buserelin | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Buserelin. | Approved |
| Buspirone | The serum concentration of Sitagliptin can be increased when it is combined with Buspirone. | Approved, Investigational |
| Cabazitaxel | The serum concentration of Sitagliptin can be increased when it is combined with Cabazitaxel. | Approved |
| Cabergoline | The serum concentration of Cabergoline can be increased when it is combined with Sitagliptin. | Approved |
| Caffeine | The serum concentration of Sitagliptin can be increased when it is combined with Caffeine. | Approved |
| Canagliflozin | The serum concentration of Sitagliptin can be increased when it is combined with Canagliflozin. | Approved |
| Candesartan | The serum concentration of Sitagliptin can be increased when it is combined with Candesartan. | Approved |
| Candoxatril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Candoxatril. | Experimental |
| Captopril | The serum concentration of Sitagliptin can be increased when it is combined with Captopril. | Approved |
| Carbamazepine | The metabolism of Sitagliptin can be increased when combined with Carbamazepine. | Approved, Investigational |
| Caroxazone | Caroxazone may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Carvedilol | The serum concentration of Sitagliptin can be increased when it is combined with Carvedilol. | Approved, Investigational |
| Caspofungin | The serum concentration of Sitagliptin can be increased when it is combined with Caspofungin. | Approved |
| Celecoxib | The metabolism of Sitagliptin can be decreased when combined with Celecoxib. | Approved, Investigational |
| Ceritinib | The serum concentration of Sitagliptin can be increased when it is combined with Ceritinib. | Approved |
| Chloroquine | The serum concentration of Sitagliptin can be increased when it is combined with Chloroquine. | Approved, Vet Approved |
| Chlorothiazide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Chlorothiazide. | Approved, Vet Approved |
| Chlorotrianisene | The serum concentration of Chlorotrianisene can be decreased when it is combined with Sitagliptin. | Withdrawn |
| Chlorpromazine | The serum concentration of Sitagliptin can be increased when it is combined with Chlorpromazine. | Approved, Vet Approved |
| Chlorpropamide | Sitagliptin may increase the hypoglycemic activities of Chlorpropamide. | Approved |
| Chlorprothixene | The serum concentration of Sitagliptin can be increased when it is combined with Chlorprothixene. | Approved, Withdrawn |
| Chlorthalidone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Chlorthalidone. | Approved |
| Cholesterol | The serum concentration of Sitagliptin can be increased when it is combined with Cholesterol. | Experimental |
| Cholic Acid | The serum concentration of Sitagliptin can be decreased when it is combined with Cholic Acid. | Approved |
| Cilazapril | The serum concentration of Sitagliptin can be increased when it is combined with Cilazapril. | Approved |
| Cimetidine | The serum concentration of Sitagliptin can be decreased when it is combined with Cimetidine. | Approved |
| Cinoxacin | Cinoxacin may increase the hypoglycemic activities of Sitagliptin. | Approved, Withdrawn |
| Ciprofloxacin | The serum concentration of Sitagliptin can be increased when it is combined with Ciprofloxacin. | Approved, Investigational |
| Cisapride | The serum concentration of Cisapride can be increased when it is combined with Sitagliptin. | Approved, Investigational, Withdrawn |
| Citalopram | The serum concentration of Sitagliptin can be increased when it is combined with Citalopram. | Approved |
| Clarithromycin | The therapeutic efficacy of Clarithromycin can be decreased when used in combination with Sitagliptin. | Approved |
| Clemastine | The metabolism of Sitagliptin can be decreased when combined with Clemastine. | Approved |
| Clofazimine | The serum concentration of Sitagliptin can be increased when it is combined with Clofazimine. | Approved, Investigational |
| Clomipramine | The serum concentration of Clomipramine can be increased when it is combined with Sitagliptin. | Approved, Vet Approved |
| Clopidogrel | The metabolism of Sitagliptin can be decreased when combined with Clopidogrel. | Approved, Nutraceutical |
| Clotrimazole | The metabolism of Sitagliptin can be decreased when combined with Clotrimazole. | Approved, Vet Approved |
| Clozapine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Clozapine. | Approved |
| Cobicistat | The metabolism of Sitagliptin can be decreased when combined with Cobicistat. | Approved |
| Colchicine | The serum concentration of Sitagliptin can be increased when it is combined with Colchicine. | Approved |
| Colforsin | The serum concentration of Sitagliptin can be increased when it is combined with Colforsin. | Experimental |
| Conivaptan | The serum concentration of Sitagliptin can be increased when it is combined with Conivaptan. | Approved, Investigational |
| Conjugated estrogens | The serum concentration of Conjugated Equine Estrogens can be decreased when it is combined with Sitagliptin. | Approved |
| Corticotropin | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Corticotropin. | Approved, Vet Approved |
| Cortisone acetate | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Cortisone acetate. | Approved |
| Crizotinib | The metabolism of Sitagliptin can be decreased when combined with Crizotinib. | Approved |
| Cyclobenzaprine | The serum concentration of Cyclobenzaprine can be increased when it is combined with Sitagliptin. | Approved |
| Cyclophosphamide | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Cyclophosphamide. | Approved, Investigational |
| Cyclosporine | The serum concentration of Cyclosporine can be increased when it is combined with Sitagliptin. | Approved, Investigational, Vet Approved |
| Cyclosporine | The metabolism of Sitagliptin can be decreased when combined with Cyclosporine. | Approved, Investigational, Vet Approved |
| Cyproterone acetate | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Cyproterone acetate. | Approved, Investigational |
| Dabrafenib | The serum concentration of Sitagliptin can be decreased when it is combined with Dabrafenib. | Approved |
| Daclatasvir | The serum concentration of Sitagliptin can be increased when it is combined with Daclatasvir. | Approved |
| Dactinomycin | The serum concentration of Sitagliptin can be increased when it is combined with Dactinomycin. | Approved |
| Danazol | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Danazol. | Approved |
| Dapoxetine | Dapoxetine may increase the hypoglycemic activities of Sitagliptin. | Investigational |
| Darunavir | The metabolism of Sitagliptin can be decreased when combined with Darunavir. | Approved |
| Dasatinib | The serum concentration of Sitagliptin can be increased when it is combined with Dasatinib. | Approved, Investigational |
| Daunorubicin | The serum concentration of Sitagliptin can be decreased when it is combined with Daunorubicin. | Approved |
| Deferasirox | The serum concentration of Sitagliptin can be decreased when it is combined with Deferasirox. | Approved, Investigational |
| Delavirdine | The serum concentration of Delavirdine can be decreased when it is combined with Sitagliptin. | Approved |
| Desipramine | The serum concentration of Desipramine can be increased when it is combined with Sitagliptin. | Approved |
| Desloratadine | The serum concentration of Sitagliptin can be increased when it is combined with Desloratadine. | Approved, Investigational |
| Desogestrel | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Desogestrel. | Approved |
| Desvenlafaxine | Desvenlafaxine may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Dexamethasone | The serum concentration of Sitagliptin can be decreased when it is combined with Dexamethasone. | Approved, Investigational, Vet Approved |
| Dextromethorphan | The serum concentration of Sitagliptin can be increased when it is combined with Dextromethorphan. | Approved |
| Diazoxide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Diazoxide. | Approved |
| Diclofenac | The serum concentration of Sitagliptin can be increased when it is combined with Diclofenac. | Approved, Vet Approved |
| Dienestrol | The serum concentration of Dienestrol can be decreased when it is combined with Sitagliptin. | Approved |
| Dienogest | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Dienogest. | Approved |
| Diethylstilbestrol | The serum concentration of Diethylstilbestrol can be decreased when it is combined with Sitagliptin. | Approved |
| Diflunisal | Diflunisal may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Digoxin | The serum concentration of Digoxin can be increased when it is combined with Sitagliptin. | Approved |
| Dihydroergotamine | The serum concentration of Dihydroergotamine can be increased when it is combined with Sitagliptin. | Approved |
| Dihydrotestosterone | Dihydrotestosterone may increase the hypoglycemic activities of Sitagliptin. | Illicit |
| Diltiazem | The metabolism of Diltiazem can be decreased when combined with Sitagliptin. | Approved |
| Dipyridamole | The serum concentration of Sitagliptin can be increased when it is combined with Dipyridamole. | Approved |
| Disopyramide | Sitagliptin may increase the hypoglycemic activities of Disopyramide. | Approved |
| Dosulepin | The serum concentration of Dosulepin can be increased when it is combined with Sitagliptin. | Approved |
| Doxazosin | The serum concentration of Sitagliptin can be increased when it is combined with Doxazosin. | Approved |
| Doxepin | The serum concentration of Doxepin can be increased when it is combined with Sitagliptin. | Approved |
| Doxorubicin | The serum concentration of Sitagliptin can be decreased when it is combined with Doxorubicin. | Approved, Investigational |
| Doxycycline | The metabolism of Sitagliptin can be decreased when combined with Doxycycline. | Approved, Investigational, Vet Approved |
| Dronabinol | The serum concentration of Sitagliptin can be increased when it is combined with Dronabinol. | Approved, Illicit |
| Dronedarone | The metabolism of Sitagliptin can be decreased when combined with Dronedarone. | Approved |
| Drospirenone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Drospirenone. | Approved |
| Duloxetine | Duloxetine may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Dyphylline | The serum concentration of Dyphylline can be decreased when it is combined with Sitagliptin. | Approved |
| Efavirenz | The serum concentration of Sitagliptin can be decreased when it is combined with Efavirenz. | Approved, Investigational |
| Elbasvir | The serum concentration of Sitagliptin can be increased when it is combined with Elbasvir. | Approved |
| Enalapril | The serum concentration of Sitagliptin can be increased when it is combined with Enalapril. | Approved, Vet Approved |
| Enalaprilat | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Enalaprilat. | Approved |
| Enfuvirtide | The serum concentration of Enfuvirtide can be increased when it is combined with Sitagliptin. | Approved, Investigational |
| Enoxacin | Enoxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Enzalutamide | The serum concentration of Sitagliptin can be decreased when it is combined with Enzalutamide. | Approved |
| Epinephrine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Epinephrine. | Approved, Vet Approved |
| Ergoloid mesylate | The serum concentration of Ergoloid mesylate can be increased when it is combined with Sitagliptin. | Approved |
| Ergonovine | The serum concentration of Ergonovine can be increased when it is combined with Sitagliptin. | Approved |
| Ergotamine | The serum concentration of Ergotamine can be increased when it is combined with Sitagliptin. | Approved |
| Erythromycin | The metabolism of Sitagliptin can be decreased when combined with Erythromycin. | Approved, Vet Approved |
| Escitalopram | Escitalopram may increase the hypoglycemic activities of Sitagliptin. | Approved, Investigational |
| Eslicarbazepine acetate | The serum concentration of Sitagliptin can be decreased when it is combined with Eslicarbazepine acetate. | Approved |
| Esmirtazapine | The serum concentration of Esmirtazapine can be increased when it is combined with Sitagliptin. | Investigational |
| Estradiol | The serum concentration of Estradiol can be decreased when it is combined with Sitagliptin. | Approved, Investigational, Vet Approved |
| Estramustine | The serum concentration of Estramustine can be decreased when it is combined with Sitagliptin. | Approved |
| Estriol | The serum concentration of Sitagliptin can be decreased when it is combined with Estriol. | Approved, Vet Approved |
| Estrogens, esterified | The serum concentration of Estrogens, esterified can be decreased when it is combined with Sitagliptin. | Approved |
| Estrone | The serum concentration of Sitagliptin can be decreased when it is combined with Estrone. | Approved |
| Estrone sulfate | The serum concentration of Estrone sulfate can be decreased when it is combined with Sitagliptin. | Approved |
| Etacrynic acid | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Etacrynic acid. | Approved |
| Ethinyl Estradiol | The serum concentration of Ethinyl Estradiol can be decreased when it is combined with Sitagliptin. | Approved |
| Ethynodiol diacetate | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Ethynodiol diacetate. | Approved |
| Etonogestrel | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Etonogestrel. | Approved, Investigational |
| Etoperidone | Etoperidone may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Etoposide | The serum concentration of Sitagliptin can be increased when it is combined with Etoposide. | Approved |
| Etravirine | The serum concentration of Etravirine can be decreased when it is combined with Sitagliptin. | Approved |
| Everolimus | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Everolimus. | Approved |
| Felodipine | The serum concentration of Sitagliptin can be increased when it is combined with Felodipine. | Approved, Investigational |
| Fentanyl | The serum concentration of Sitagliptin can be increased when it is combined with Fentanyl. | Approved, Illicit, Investigational, Vet Approved |
| Fexofenadine | The serum concentration of Sitagliptin can be increased when it is combined with Fexofenadine. | Approved |
| Fidaxomicin | The serum concentration of Sitagliptin can be increased when it is combined with Fidaxomicin. | Approved |
| Fleroxacin | Fleroxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Fluconazole | The metabolism of Sitagliptin can be decreased when combined with Fluconazole. | Approved |
| Fludrocortisone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Fludrocortisone. | Approved |
| Flumequine | Flumequine may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Fluoxetine | The serum concentration of Sitagliptin can be increased when it is combined with Fluoxetine. | Approved, Vet Approved |
| Fluoxymesterone | Fluoxymesterone may increase the hypoglycemic activities of Sitagliptin. | Approved, Illicit |
| Flupentixol | The serum concentration of Sitagliptin can be increased when it is combined with Flupentixol. | Approved, Withdrawn |
| Fluphenazine | The serum concentration of Sitagliptin can be increased when it is combined with Fluphenazine. | Approved |
| Flurazepam | The serum concentration of Sitagliptin can be increased when it is combined with Flurazepam. | Approved, Illicit |
| Fluvoxamine | The metabolism of Sitagliptin can be decreased when combined with Fluvoxamine. | Approved, Investigational |
| Fosamprenavir | The metabolism of Sitagliptin can be decreased when combined with Fosamprenavir. | Approved |
| Fosaprepitant | The serum concentration of Sitagliptin can be increased when it is combined with Fosaprepitant. | Approved |
| Fosinopril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Fosinopril. | Approved |
| Fosphenytoin | The metabolism of Sitagliptin can be increased when combined with Fosphenytoin. | Approved |
| Furazolidone | Furazolidone may increase the hypoglycemic activities of Sitagliptin. | Approved, Vet Approved |
| Furosemide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Furosemide. | Approved, Vet Approved |
| Fusidic Acid | The serum concentration of Sitagliptin can be increased when it is combined with Fusidic Acid. | Approved |
| Gatifloxacin | Gatifloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved, Investigational |
| Gefitinib | The serum concentration of Sitagliptin can be increased when it is combined with Gefitinib. | Approved, Investigational |
| Gemfibrozil | The metabolism of Sitagliptin can be decreased when combined with Gemfibrozil. | Approved |
| Gemifloxacin | Gemifloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved, Investigational |
| Genistein | The serum concentration of Sitagliptin can be increased when it is combined with Genistein. | Investigational |
| Glibornuride | Sitagliptin may increase the hypoglycemic activities of Glibornuride. | Withdrawn |
| Gliclazide | Sitagliptin may increase the hypoglycemic activities of Gliclazide. | Approved |
| Glimepiride | Sitagliptin may increase the hypoglycemic activities of Glimepiride. | Approved |
| Glipizide | Sitagliptin may increase the hypoglycemic activities of Glipizide. | Approved |
| Gliquidone | Sitagliptin may increase the hypoglycemic activities of Gliquidone. | Approved |
| Glisoxepide | Sitagliptin may increase the hypoglycemic activities of Glisoxepide. | Approved |
| Glyburide | Sitagliptin may increase the hypoglycemic activities of Glyburide. | Approved |
| Goserelin | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Goserelin. | Approved |
| Gramicidin D | The serum concentration of Sitagliptin can be increased when it is combined with Gramicidin D. | Approved |
| Grepafloxacin | The serum concentration of Sitagliptin can be increased when it is combined with Grepafloxacin. | Withdrawn |
| Haloperidol | The serum concentration of Sitagliptin can be increased when it is combined with Haloperidol. | Approved |
| Hexestrol | The serum concentration of Hexestrol can be decreased when it is combined with Sitagliptin. | Withdrawn |
| Histrelin | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Histrelin. | Approved |
| Hydracarbazine | Hydracarbazine may increase the hypoglycemic activities of Sitagliptin. | Experimental |
| Hydrochlorothiazide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Hydrochlorothiazide. | Approved, Vet Approved |
| Hydrocortisone | The serum concentration of Sitagliptin can be increased when it is combined with Hydrocortisone. | Approved, Vet Approved |
| Hydroflumethiazide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Hydroflumethiazide. | Approved |
| Hydroxyprogesterone caproate | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Hydroxyprogesterone caproate. | Approved |
| Idelalisib | The serum concentration of Sitagliptin can be increased when it is combined with Idelalisib. | Approved |
| Iloperidone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Iloperidone. | Approved |
| Imatinib | The metabolism of Sitagliptin can be decreased when combined with Imatinib. | Approved |
| Imidapril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Imidapril. | Investigational |
| Imipramine | The serum concentration of Imipramine can be increased when it is combined with Sitagliptin. | Approved |
| Indalpine | Indalpine may increase the hypoglycemic activities of Sitagliptin. | Investigational, Withdrawn |
| Indapamide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Indapamide. | Approved |
| Indinavir | The metabolism of Sitagliptin can be decreased when combined with Indinavir. | Approved |
| Indomethacin | The serum concentration of Sitagliptin can be increased when it is combined with Indomethacin. | Approved, Investigational |
| Insulin Aspart | Sitagliptin may increase the hypoglycemic activities of Insulin Aspart. | Approved |
| Insulin Detemir | Sitagliptin may increase the hypoglycemic activities of Insulin Detemir. | Approved |
| Insulin Glargine | Sitagliptin may increase the hypoglycemic activities of Insulin Glargine. | Approved |
| Insulin Glulisine | Sitagliptin may increase the hypoglycemic activities of Insulin Glulisine. | Approved |
| Insulin Human | Sitagliptin may increase the hypoglycemic activities of Insulin Human. | Approved, Investigational |
| Insulin Lispro | Sitagliptin may increase the hypoglycemic activities of Insulin Lispro. | Approved |
| Insulin Pork | Sitagliptin may increase the hypoglycemic activities of Insulin Pork. | Approved |
| Iproclozide | Iproclozide may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Iproniazid | Iproniazid may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Irbesartan | The metabolism of Sitagliptin can be decreased when combined with Irbesartan. | Approved, Investigational |
| Isavuconazonium | The metabolism of Sitagliptin can be decreased when combined with Isavuconazonium. | Approved, Investigational |
| Isocarboxazid | Isocarboxazid may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Isradipine | The metabolism of Sitagliptin can be decreased when combined with Isradipine. | Approved |
| Itraconazole | The metabolism of Sitagliptin can be decreased when combined with Itraconazole. | Approved, Investigational |
| Ivacaftor | The serum concentration of Sitagliptin can be increased when it is combined with Ivacaftor. | Approved |
| Ivermectin | The serum concentration of Sitagliptin can be increased when it is combined with Ivermectin. | Approved, Vet Approved |
| Ketamine | The serum concentration of Sitagliptin can be increased when it is combined with Ketamine. | Approved, Vet Approved |
| Ketoconazole | The metabolism of Sitagliptin can be decreased when combined with Ketoconazole. | Approved, Investigational |
| Lanreotide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Lanreotide. | Approved |
| Lansoprazole | The serum concentration of Sitagliptin can be increased when it is combined with Lansoprazole. | Approved, Investigational |
| Lapatinib | The serum concentration of Sitagliptin can be increased when it is combined with Lapatinib. | Approved, Investigational |
| Leuprolide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Leuprolide. | Approved, Investigational |
| Levofloxacin | The serum concentration of Sitagliptin can be increased when it is combined with Levofloxacin. | Approved, Investigational |
| Levomilnacipran | Levomilnacipran may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Levonorgestrel | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Levonorgestrel. | Approved, Investigational |
| Levothyroxine | The serum concentration of Sitagliptin can be decreased when it is combined with Levothyroxine. | Approved |
| Lidocaine | The serum concentration of Sitagliptin can be increased when it is combined with Lidocaine. | Approved, Vet Approved |
| Liothyronine | The serum concentration of Sitagliptin can be decreased when it is combined with Liothyronine. | Approved, Vet Approved |
| Liotrix | The serum concentration of Sitagliptin can be decreased when it is combined with Liotrix. | Approved |
| Lipoic Acid | Lipoic Acid may increase the hypoglycemic activities of Sitagliptin. | Approved, Nutraceutical |
| Lisinopril | The serum concentration of Sitagliptin can be increased when it is combined with Lisinopril. | Approved, Investigational |
| Lomefloxacin | Lomefloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Lomitapide | The serum concentration of Sitagliptin can be increased when it is combined with Lomitapide. | Approved |
| Loperamide | The serum concentration of Sitagliptin can be increased when it is combined with Loperamide. | Approved |
| Lopinavir | The metabolism of Sitagliptin can be decreased when combined with Lopinavir. | Approved |
| Loratadine | The serum concentration of Sitagliptin can be increased when it is combined with Loratadine. | Approved |
| Losartan | The serum concentration of Sitagliptin can be increased when it is combined with Losartan. | Approved |
| Lovastatin | The serum concentration of Lovastatin can be increased when it is combined with Sitagliptin. | Approved, Investigational |
| Luliconazole | The serum concentration of Sitagliptin can be increased when it is combined with Luliconazole. | Approved |
| Lumacaftor | The serum concentration of Sitagliptin can be increased when it is combined with Lumacaftor. | Approved |
| Lurasidone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Lurasidone. | Approved |
| Maprotiline | The serum concentration of Sitagliptin can be increased when it is combined with Maprotiline. | Approved |
| Mebanazine | Mebanazine may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Mebendazole | The serum concentration of Sitagliptin can be increased when it is combined with Mebendazole. | Approved, Vet Approved |
| Mecasermin | Sitagliptin may increase the hypoglycemic activities of Mecasermin. | Approved, Investigational |
| Medroxyprogesterone acetate | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Medroxyprogesterone acetate. | Approved, Investigational |
| Mefloquine | The serum concentration of Sitagliptin can be increased when it is combined with Mefloquine. | Approved |
| Megestrol acetate | The serum concentration of Sitagliptin can be increased when it is combined with Megestrol acetate. | Approved, Vet Approved |
| Meprobamate | The serum concentration of Sitagliptin can be increased when it is combined with Meprobamate. | Approved, Illicit |
| Mesalazine | Mesalazine may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Mestranol | The serum concentration of Mestranol can be decreased when it is combined with Sitagliptin. | Approved |
| Methadone | The serum concentration of Sitagliptin can be increased when it is combined with Methadone. | Approved |
| Methallenestril | The serum concentration of Methallenestril can be decreased when it is combined with Sitagliptin. | Experimental |
| Methotrimeprazine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Methotrimeprazine. | Approved |
| Methyclothiazide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Methyclothiazide. | Approved |
| Methylene blue | Methylene blue may increase the hypoglycemic activities of Sitagliptin. | Investigational |
| Methylprednisolone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Methylprednisolone. | Approved, Vet Approved |
| Methyltestosterone | Methyltestosterone may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Metolazone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Metolazone. | Approved |
| Metoprolol | The serum concentration of Sitagliptin can be increased when it is combined with Metoprolol. | Approved, Investigational |
| Mibefradil | The serum concentration of Sitagliptin can be increased when it is combined with Mibefradil. | Withdrawn |
| Miconazole | The serum concentration of Sitagliptin can be increased when it is combined with Miconazole. | Approved, Investigational, Vet Approved |
| Midazolam | The serum concentration of Midazolam can be increased when it is combined with Sitagliptin. | Approved, Illicit |
| Mifepristone | The serum concentration of Sitagliptin can be increased when it is combined with Mifepristone. | Approved, Investigational |
| Milnacipran | Milnacipran may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Minaprine | Minaprine may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Mirtazapine | The serum concentration of Mirtazapine can be increased when it is combined with Sitagliptin. | Approved |
| Mitomycin | The serum concentration of Sitagliptin can be increased when it is combined with Mitomycin. | Approved |
| Mitotane | The serum concentration of Sitagliptin can be decreased when it is combined with Mitotane. | Approved |
| Mitoxantrone | The serum concentration of Sitagliptin can be decreased when it is combined with Mitoxantrone. | Approved, Investigational |
| Moclobemide | Moclobemide may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Modafinil | The serum concentration of Sitagliptin can be decreased when it is combined with Modafinil. | Approved, Investigational |
| Moexipril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Moexipril. | Approved |
| Morphine | The serum concentration of Sitagliptin can be increased when it is combined with Morphine. | Approved, Investigational |
| Moxifloxacin | Moxifloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved, Investigational |
| Nafcillin | The serum concentration of Sitagliptin can be decreased when it is combined with Nafcillin. | Approved |
| Nalidixic Acid | Nalidixic Acid may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Naltrexone | The serum concentration of Sitagliptin can be increased when it is combined with Naltrexone. | Approved, Investigational, Vet Approved |
| Naringenin | The serum concentration of Sitagliptin can be increased when it is combined with Naringenin. | Experimental |
| Nateglinide | Sitagliptin may increase the hypoglycemic activities of Nateglinide. | Approved, Investigational |
| NCX 4016 | NCX 4016 may increase the hypoglycemic activities of Sitagliptin. | Investigational |
| Nefazodone | The serum concentration of Nefazodone can be increased when it is combined with Sitagliptin. | Approved, Withdrawn |
| Nelfinavir | The metabolism of Sitagliptin can be decreased when combined with Nelfinavir. | Approved |
| Neostigmine | The serum concentration of Sitagliptin can be increased when it is combined with Neostigmine. | Approved, Vet Approved |
| Netupitant | The serum concentration of Sitagliptin can be increased when it is combined with Netupitant. | Approved |
| Nevirapine | The metabolism of Sitagliptin can be increased when combined with Nevirapine. | Approved |
| Niacin | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Niacin. | Approved, Investigational, Nutraceutical |
| Nialamide | Nialamide may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Nicardipine | The serum concentration of Sitagliptin can be increased when it is combined with Nicardipine. | Approved |
| Nifedipine | The serum concentration of Sitagliptin can be decreased when it is combined with Nifedipine. | Approved |
| Nilotinib | The metabolism of Sitagliptin can be decreased when combined with Nilotinib. | Approved, Investigational |
| Nisoldipine | The serum concentration of Sitagliptin can be increased when it is combined with Nisoldipine. | Approved |
| Nitrazepam | The serum concentration of Sitagliptin can be increased when it is combined with Nitrazepam. | Approved |
| Nitrendipine | The serum concentration of Sitagliptin can be increased when it is combined with Nitrendipine. | Approved |
| Nitroaspirin | Nitroaspirin may increase the hypoglycemic activities of Sitagliptin. | Investigational |
| Norethisterone | The serum concentration of Sitagliptin can be decreased when it is combined with Norethisterone. | Approved |
| Norfloxacin | Norfloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Norgestimate | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Norgestimate. | Approved |
| Nortriptyline | The serum concentration of Nortriptyline can be increased when it is combined with Sitagliptin. | Approved |
| Octamoxin | Octamoxin may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Octreotide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Octreotide. | Approved, Investigational |
| Ofloxacin | Ofloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Olanzapine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Olanzapine. | Approved, Investigational |
| Olaparib | The metabolism of Sitagliptin can be decreased when combined with Olaparib. | Approved |
| Olsalazine | Olsalazine may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Omapatrilat | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Omapatrilat. | Investigational |
| Omeprazole | The serum concentration of Sitagliptin can be increased when it is combined with Omeprazole. | Approved, Investigational, Vet Approved |
| Opipramol | The serum concentration of Opipramol can be increased when it is combined with Sitagliptin. | Investigational |
| Osimertinib | The serum concentration of Sitagliptin can be increased when it is combined with Osimertinib. | Approved |
| Oxandrolone | Oxandrolone may increase the hypoglycemic activities of Sitagliptin. | Approved, Investigational |
| Oxymetholone | Oxymetholone may increase the hypoglycemic activities of Sitagliptin. | Approved, Illicit |
| P-Nitrophenol | The serum concentration of Sitagliptin can be increased when it is combined with P-Nitrophenol. | Experimental |
| Paclitaxel | The serum concentration of Sitagliptin can be increased when it is combined with Paclitaxel. | Approved, Vet Approved |
| Palbociclib | The serum concentration of Sitagliptin can be increased when it is combined with Palbociclib. | Approved |
| Paliperidone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Paliperidone. | Approved |
| Palmitic Acid | The serum concentration of Sitagliptin can be increased when it is combined with Palmitic Acid. | Experimental |
| Pantoprazole | The serum concentration of Sitagliptin can be increased when it is combined with Pantoprazole. | Approved |
| Pargyline | Pargyline may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Paroxetine | The serum concentration of Sitagliptin can be increased when it is combined with Paroxetine. | Approved, Investigational |
| Pasireotide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Pasireotide. | Approved |
| Pazufloxacin | Pazufloxacin may increase the hypoglycemic activities of Sitagliptin. | Investigational |
| Pefloxacin | Pefloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Pegvisomant | Pegvisomant may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Pentamidine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Pentamidine. | Approved |
| Pentobarbital | The metabolism of Sitagliptin can be increased when combined with Pentobarbital. | Approved, Vet Approved |
| Perindopril | The serum concentration of Sitagliptin can be increased when it is combined with Perindopril. | Approved |
| Pethidine | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Pethidine. | Approved |
| Phenelzine | Phenelzine may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Pheniprazine | Pheniprazine may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Phenobarbital | The metabolism of Sitagliptin can be increased when combined with Phenobarbital. | Approved |
| Phenoxypropazine | Phenoxypropazine may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Phenytoin | The metabolism of Sitagliptin can be increased when combined with Phenytoin. | Approved, Vet Approved |
| Pimozide | The serum concentration of Pimozide can be increased when it is combined with Sitagliptin. | Approved |
| Pioglitazone | The metabolism of Sitagliptin can be decreased when combined with Pioglitazone. | Approved, Investigational |
| Piperazine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Piperazine. | Approved, Vet Approved |
| Pipotiazine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Pipotiazine. | Approved |
| Pirlindole | Pirlindole may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Pivhydrazine | Pivhydrazine may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Platelet Activating Factor | The serum concentration of Sitagliptin can be decreased when it is combined with Platelet Activating Factor. | Experimental |
| Polythiazide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Polythiazide. | Approved |
| Ponatinib | The serum concentration of Sitagliptin can be increased when it is combined with Ponatinib. | Approved |
| Posaconazole | The metabolism of Sitagliptin can be decreased when combined with Posaconazole. | Approved, Investigational, Vet Approved |
| Pravastatin | The serum concentration of Sitagliptin can be increased when it is combined with Pravastatin. | Approved |
| Prazosin | The serum concentration of Sitagliptin can be increased when it is combined with Prazosin. | Approved |
| Prednisolone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Prednisolone. | Approved, Vet Approved |
| Prednisone | The serum concentration of Sitagliptin can be increased when it is combined with Prednisone. | Approved, Vet Approved |
| Primidone | The metabolism of Sitagliptin can be increased when combined with Primidone. | Approved, Vet Approved |
| Probenecid | The serum concentration of Sitagliptin can be increased when it is combined with Probenecid. | Approved |
| Progesterone | The serum concentration of Sitagliptin can be decreased when it is combined with Progesterone. | Approved, Vet Approved |
| Promethazine | The serum concentration of Sitagliptin can be increased when it is combined with Promethazine. | Approved |
| Propafenone | The serum concentration of Sitagliptin can be increased when it is combined with Propafenone. | Approved |
| Propranolol | The serum concentration of Sitagliptin can be increased when it is combined with Propranolol. | Approved, Investigational |
| Protriptyline | The serum concentration of Protriptyline can be increased when it is combined with Sitagliptin. | Approved |
| Prulifloxacin | Prulifloxacin may increase the hypoglycemic activities of Sitagliptin. | Investigational |
| Quercetin | The serum concentration of Sitagliptin can be increased when it is combined with Quercetin. | Experimental |
| Quetiapine | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Quetiapine. | Approved |
| Quinacrine | The serum concentration of Sitagliptin can be increased when it is combined with Quinacrine. | Approved |
| Quinapril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Quinapril. | Approved, Investigational |
| Quinethazone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Quinethazone. | Approved |
| Quinidine | The serum concentration of Sitagliptin can be increased when it is combined with Quinidine. | Approved |
| Quinine | The serum concentration of Sitagliptin can be increased when it is combined with Quinine. | Approved |
| Rabeprazole | The metabolism of Sitagliptin can be decreased when combined with Rabeprazole. | Approved, Investigational |
| Ramipril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Ramipril. | Approved |
| Ranitidine | The serum concentration of Sitagliptin can be increased when it is combined with Ranitidine. | Approved |
| Ranolazine | The serum concentration of Sitagliptin can be increased when it is combined with Ranolazine. | Approved, Investigational |
| Rasagiline | Rasagiline may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Reboxetine | The serum concentration of Sitagliptin can be increased when it is combined with Reboxetine. | Approved, Investigational |
| Regorafenib | The serum concentration of Sitagliptin can be increased when it is combined with Regorafenib. | Approved |
| Repaglinide | Sitagliptin may increase the hypoglycemic activities of Repaglinide. | Approved, Investigational |
| Rescinnamine | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Rescinnamine. | Approved |
| Reserpine | The serum concentration of Sitagliptin can be decreased when it is combined with Reserpine. | Approved |
| Rifabutin | The metabolism of Sitagliptin can be increased when combined with Rifabutin. | Approved |
| Rifampicin | The metabolism of Sitagliptin can be increased when combined with Rifampicin. | Approved |
| Rifapentine | The metabolism of Sitagliptin can be increased when combined with Rifapentine. | Approved |
| Rilpivirine | The serum concentration of Sitagliptin can be increased when it is combined with Rilpivirine. | Approved |
| Riociguat | The serum concentration of Riociguat can be increased when it is combined with Sitagliptin. | Approved |
| Risperidone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Risperidone. | Approved, Investigational |
| Ritonavir | The metabolism of Sitagliptin can be decreased when combined with Ritonavir. | Approved, Investigational |
| Rolapitant | The serum concentration of Sitagliptin can be increased when it is combined with Rolapitant. | Approved |
| Rosiglitazone | The metabolism of Sitagliptin can be decreased when combined with Rosiglitazone. | Approved, Investigational |
| Rosoxacin | Rosoxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Rosuvastatin | The serum concentration of Rosuvastatin can be increased when it is combined with Sitagliptin. | Approved |
| Safrazine | Safrazine may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Salicylic acid | Salicylic acid may increase the hypoglycemic activities of Sitagliptin. | Approved, Vet Approved |
| Saquinavir | The metabolism of Sitagliptin can be decreased when combined with Saquinavir. | Approved, Investigational |
| Scopolamine | The serum concentration of Sitagliptin can be increased when it is combined with Scopolamine. | Approved |
| Secobarbital | The metabolism of Sitagliptin can be increased when combined with Secobarbital. | Approved, Vet Approved |
| Selegiline | Selegiline may increase the hypoglycemic activities of Sitagliptin. | Approved, Investigational, Vet Approved |
| Sertraline | The serum concentration of Sitagliptin can be increased when it is combined with Sertraline. | Approved |
| Sildenafil | The serum concentration of Sildenafil can be increased when it is combined with Sitagliptin. | Approved, Investigational |
| Siltuximab | The serum concentration of Sitagliptin can be decreased when it is combined with Siltuximab. | Approved |
| Simeprevir | The serum concentration of Simeprevir can be increased when it is combined with Sitagliptin. | Approved |
| Simvastatin | The serum concentration of Simvastatin can be increased when it is combined with Sitagliptin. | Approved |
| Sirolimus | The serum concentration of Sitagliptin can be decreased when it is combined with Sirolimus. | Approved, Investigational |
| Sorafenib | The serum concentration of Sitagliptin can be increased when it is combined with Sorafenib. | Approved, Investigational |
| Sparfloxacin | Sparfloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Spirapril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Spirapril. | Approved |
| Spironolactone | The serum concentration of Sitagliptin can be increased when it is combined with Spironolactone. | Approved |
| St. John's Wort | The metabolism of Sitagliptin can be increased when combined with St. John's Wort. | Nutraceutical |
| Stanozolol | Stanozolol may increase the hypoglycemic activities of Sitagliptin. | Approved, Vet Approved |
| Staurosporine | The serum concentration of Sitagliptin can be increased when it is combined with Staurosporine. | Experimental |
| Stiripentol | The serum concentration of Sitagliptin can be increased when it is combined with Stiripentol. | Approved |
| Streptozocin | The serum concentration of Sitagliptin can be decreased when it is combined with Streptozocin. | Approved |
| Sulfadiazine | Sitagliptin may increase the hypoglycemic activities of Sulfadiazine. | Approved, Vet Approved |
| Sulfamethoxazole | The metabolism of Sitagliptin can be decreased when combined with Sulfamethoxazole. | Approved |
| Sulfinpyrazone | The serum concentration of Sitagliptin can be increased when it is combined with Sulfinpyrazone. | Approved |
| Sulfisoxazole | The metabolism of Sitagliptin can be decreased when combined with Sulfisoxazole. | Approved, Vet Approved |
| Sumatriptan | The serum concentration of Sitagliptin can be increased when it is combined with Sumatriptan. | Approved, Investigational |
| Sunitinib | The serum concentration of Sitagliptin can be increased when it is combined with Sunitinib. | Approved, Investigational |
| Synthetic Conjugated Estrogens, A | The serum concentration of Synthetic Conjugated Estrogens, A can be decreased when it is combined with Sitagliptin. | Approved |
| Tacrine | The serum concentration of Sitagliptin can be increased when it is combined with Tacrine. | Withdrawn |
| Tacrolimus | The metabolism of Tacrolimus can be decreased when combined with Sitagliptin. | Approved, Investigational |
| Tacrolimus | The serum concentration of Sitagliptin can be decreased when it is combined with Tacrolimus. | Approved, Investigational |
| Tamoxifen | The serum concentration of Sitagliptin can be decreased when it is combined with Tamoxifen. | Approved |
| Taurocholic Acid | The serum concentration of Sitagliptin can be increased when it is combined with Taurocholic Acid. | Experimental |
| Telaprevir | The metabolism of Sitagliptin can be decreased when combined with Telaprevir. | Withdrawn |
| Telithromycin | The metabolism of Sitagliptin can be decreased when combined with Telithromycin. | Approved |
| Telmisartan | The serum concentration of Sitagliptin can be increased when it is combined with Telmisartan. | Approved, Investigational |
| Temafloxacin | Temafloxacin may increase the hypoglycemic activities of Sitagliptin. | Withdrawn |
| Temocapril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Temocapril. | Experimental, Investigational |
| Temsirolimus | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Temsirolimus. | Approved |
| Terazosin | The serum concentration of Sitagliptin can be increased when it is combined with Terazosin. | Approved |
| Terfenadine | The serum concentration of Sitagliptin can be increased when it is combined with Terfenadine. | Withdrawn |
| Teriflunomide | The metabolism of Sitagliptin can be decreased when combined with Teriflunomide. | Approved |
| Tesmilifene | The serum concentration of Sitagliptin can be decreased when it is combined with Tesmilifene. | Investigational |
| Testosterone | The serum concentration of Sitagliptin can be increased when it is combined with Testosterone. | Approved, Investigational |
| Theophylline | The serum concentration of Theophylline can be decreased when it is combined with Sitagliptin. | Approved |
| Tianeptine | The serum concentration of Tianeptine can be increased when it is combined with Sitagliptin. | Approved |
| Ticagrelor | The serum concentration of Sitagliptin can be increased when it is combined with Ticagrelor. | Approved |
| Ticlopidine | The metabolism of Sitagliptin can be decreased when combined with Ticlopidine. | Approved |
| Tipranavir | The serum concentration of Sitagliptin can be decreased when it is combined with Tipranavir. | Approved, Investigational |
| Tocilizumab | The serum concentration of Sitagliptin can be decreased when it is combined with Tocilizumab. | Approved |
| Tolazamide | Sitagliptin may increase the hypoglycemic activities of Tolazamide. | Approved |
| Tolbutamide | Sitagliptin may increase the hypoglycemic activities of Tolbutamide. | Approved |
| Toloxatone | Toloxatone may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Tolvaptan | The serum concentration of Sitagliptin can be increased when it is combined with Tolvaptan. | Approved |
| Torasemide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Torasemide. | Approved |
| Trandolapril | The risk or severity of adverse effects can be increased when Sitagliptin is combined with Trandolapril. | Approved |
| Trans-2-Phenylcyclopropylamine | Trans-2-Phenylcyclopropylamine may increase the hypoglycemic activities of Sitagliptin. | Experimental |
| Tranylcypromine | Tranylcypromine may increase the hypoglycemic activities of Sitagliptin. | Approved |
| Trazodone | The serum concentration of Sitagliptin can be decreased when it is combined with Trazodone. | Approved, Investigational |
| Triamcinolone | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Triamcinolone. | Approved, Vet Approved |
| Triazolam | The serum concentration of Triazolam can be increased when it is combined with Sitagliptin. | Approved |
| Trichlormethiazide | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Trichlormethiazide. | Approved, Vet Approved |
| Trifluoperazine | The serum concentration of Sitagliptin can be increased when it is combined with Trifluoperazine. | Approved |
| Triflupromazine | The serum concentration of Sitagliptin can be increased when it is combined with Triflupromazine. | Approved, Vet Approved |
| Trimethoprim | The serum concentration of Sitagliptin can be decreased when it is combined with Trimethoprim. | Approved, Vet Approved |
| Trimipramine | The serum concentration of Trimipramine can be increased when it is combined with Sitagliptin. | Approved |
| Triptorelin | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Triptorelin. | Approved, Vet Approved |
| Trovafloxacin | Trovafloxacin may increase the hypoglycemic activities of Sitagliptin. | Approved, Withdrawn |
| Valproic Acid | The serum concentration of Valproic Acid can be decreased when it is combined with Sitagliptin. | Approved, Investigational |
| Venlafaxine | The metabolism of Sitagliptin can be decreased when combined with Venlafaxine. | Approved |
| Verapamil | The metabolism of Verapamil can be decreased when combined with Sitagliptin. | Approved |
| Vinblastine | The serum concentration of Sitagliptin can be decreased when it is combined with Vinblastine. | Approved |
| Vincristine | The serum concentration of Sitagliptin can be decreased when it is combined with Vincristine. | Approved, Investigational |
| Vinorelbine | The serum concentration of Sitagliptin can be increased when it is combined with Vinorelbine. | Approved, Investigational |
| Voriconazole | The metabolism of Sitagliptin can be decreased when combined with Voriconazole. | Approved, Investigational |
| Vorinostat | The therapeutic efficacy of Sitagliptin can be decreased when used in combination with Vorinostat. | Approved, Investigational |
| Zidovudine | The serum concentration of Zidovudine can be decreased when it is combined with Sitagliptin. | Approved |
| Zimelidine | The serum concentration of Sitagliptin can be increased when it is combined with Zimelidine. | Withdrawn |
| Ziprasidone | The metabolism of Sitagliptin can be decreased when combined with Ziprasidone. | Approved |