| 2,5-Dimethoxy-4-ethylamphetamine | 2,5-Dimethoxy-4-ethylamphetamine may increase the analgesic activities of Butorphanol. | Experimental, Illicit |
| 3,4-Methylenedioxyamphetamine | 3,4-Methylenedioxyamphetamine may increase the analgesic activities of Butorphanol. | Experimental, Illicit |
| 3,4-Methylenedioxymethamphetamine | 3,4-Methylenedioxymethamphetamine may increase the analgesic activities of Butorphanol. | Experimental, Illicit |
| 4-Bromo-2,5-dimethoxyamphetamine | 4-Bromo-2,5-dimethoxyamphetamine may increase the analgesic activities of Butorphanol. | Experimental, Illicit |
| 7-Nitroindazole | The risk or severity of adverse effects can be increased when Butorphanol is combined with 7-Nitroindazole. | Experimental |
| Acepromazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Acepromazine. | Approved, Vet Approved |
| Aceprometazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Aceprometazine. | Approved |
| Acetazolamide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Acetazolamide. | Approved, Vet Approved |
| Aclidinium | The risk or severity of adverse effects can be increased when Aclidinium is combined with Butorphanol. | Approved |
| Adipiplon | The risk or severity of adverse effects can be increased when Butorphanol is combined with adipiplon. | Investigational |
| Agomelatine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Agomelatine. | Approved, Investigational |
| Alfaxalone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Alfaxalone. | Vet Approved |
| Alfentanil | Butorphanol may decrease the analgesic activities of Alfentanil. | Approved, Illicit |
| Alimemazine | Alimemazine may increase the hypotensive activities of Butorphanol. | Approved, Vet Approved |
| Allopregnanolone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Sage 547. | Investigational |
| Alphacetylmethadol | Butorphanol may decrease the analgesic activities of Alphacetylmethadol. | Experimental, Illicit |
| Alprazolam | The risk or severity of adverse effects can be increased when Alprazolam is combined with Butorphanol. | Approved, Illicit, Investigational |
| Alvimopan | The risk or severity of adverse effects can be increased when Butorphanol is combined with Alvimopan. | Approved |
| Amiloride | The risk or severity of adverse effects can be increased when Butorphanol is combined with Amiloride. | Approved |
| Amisulpride | The risk or severity of adverse effects can be increased when Butorphanol is combined with Amisulpride. | Approved, Investigational |
| Amitriptyline | The risk or severity of adverse effects can be increased when Butorphanol is combined with Amitriptyline. | Approved |
| Ammonium chloride | Ammonium chloride may increase the excretion rate of Butorphanol which could result in a lower serum level and potentially a reduction in efficacy. | Approved, Vet Approved |
| Amobarbital | The risk or severity of adverse effects can be increased when Butorphanol is combined with Amobarbital. | Approved, Illicit |
| Amoxapine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Amoxapine. | Approved |
| Amperozide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Amperozide. | Experimental |
| Amphetamine | Amphetamine may increase the analgesic activities of Butorphanol. | Approved, Illicit |
| Anisotropine Methylbromide | The risk or severity of adverse effects can be increased when Anisotropine Methylbromide is combined with Butorphanol. | Approved |
| Aripiprazole | The risk or severity of adverse effects can be increased when Butorphanol is combined with Aripiprazole. | Approved, Investigational |
| Articaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Articaine. | Approved |
| Asenapine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Asenapine. | Approved |
| Atracurium besylate | The risk or severity of adverse effects can be increased when Atracurium besylate is combined with Butorphanol. | Approved |
| Atropine | The risk or severity of adverse effects can be increased when Atropine is combined with Butorphanol. | Approved, Vet Approved |
| Azelastine | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Azelastine. | Approved |
| Azelastine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Azelastine. | Approved |
| Azosemide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Azosemide. | Investigational |
| Baclofen | The risk or severity of adverse effects can be increased when Butorphanol is combined with Baclofen. | Approved |
| Barbital | The risk or severity of adverse effects can be increased when Butorphanol is combined with Barbital. | Illicit |
| Benactyzine | The risk or severity of adverse effects can be increased when Benactyzine is combined with Butorphanol. | Withdrawn |
| Bendroflumethiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Bendroflumethiazide. | Approved |
| Benperidol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Benperidol. | Investigational |
| Benzatropine | The risk or severity of adverse effects can be increased when Benzatropine is combined with Butorphanol. | Approved |
| Benzocaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Benzocaine. | Approved |
| Benzphetamine | Benzphetamine may increase the analgesic activities of Butorphanol. | Approved, Illicit |
| Benzyl alcohol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Benzyl alcohol. | Approved |
| Bezitramide | Butorphanol may decrease the analgesic activities of Bezitramide. | Experimental, Illicit, Withdrawn |
| Biperiden | The risk or severity of adverse effects can be increased when Biperiden is combined with Butorphanol. | Approved |
| BL-1020 | BL-1020 may increase the hypotensive activities of Butorphanol. | Investigational |
| Brexpiprazole | The risk or severity of adverse effects can be increased when Butorphanol is combined with Brexpiprazole. | Approved |
| Brimonidine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Brimonidine. | Approved |
| Brimonidine | Brimonidine may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved |
| Bromazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Bromazepam. | Approved, Illicit |
| Brompheniramine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Brompheniramine. | Approved |
| Brotizolam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Brotizolam. | Approved, Withdrawn |
| Bumetanide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Bumetanide. | Approved |
| Bupivacaine | The risk or severity of adverse effects can be increased when Bupivacaine is combined with Butorphanol. | Approved, Investigational |
| Buprenorphine | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Buprenorphine. | Approved, Illicit, Investigational, Vet Approved |
| Buspirone | The risk or severity of adverse effects can be increased when Buspirone is combined with Butorphanol. | Approved, Investigational |
| Butabarbital | The risk or severity of adverse effects can be increased when Butabarbital is combined with Butorphanol. | Approved, Illicit |
| Butalbital | The risk or severity of adverse effects can be increased when Butorphanol is combined with Butalbital. | Approved, Illicit |
| Butethal | The risk or severity of adverse effects can be increased when Butorphanol is combined with Butethal. | Approved, Illicit |
| Canrenoic acid | The risk or severity of adverse effects can be increased when Butorphanol is combined with Canrenoic acid. | Approved, Withdrawn |
| Canrenone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Canrenone. | Investigational |
| Carbamazepine | The risk or severity of adverse effects can be increased when Carbamazepine is combined with Butorphanol. | Approved, Investigational |
| Carbinoxamine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Carbinoxamine. | Approved |
| Carfentanil | Butorphanol may decrease the analgesic activities of Carfentanil. | Illicit, Vet Approved |
| Carisoprodol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Carisoprodol. | Approved |
| Cetirizine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Cetirizine. | Approved |
| Chloral hydrate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chloral hydrate. | Approved, Illicit, Vet Approved |
| Chlordiazepoxide | The risk or severity of adverse effects can be increased when Chlordiazepoxide is combined with Butorphanol. | Approved, Illicit |
| Chlormezanone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chlormezanone. | Approved, Withdrawn |
| Chloroprocaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chloroprocaine. | Approved |
| Chlorothiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chlorothiazide. | Approved, Vet Approved |
| Chlorphenamine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chlorphenamine. | Approved |
| Chlorphenoxamine | The risk or severity of adverse effects can be increased when Chlorphenoxamine is combined with Butorphanol. | Withdrawn |
| Chlorphentermine | Chlorphentermine may increase the analgesic activities of Butorphanol. | Illicit, Withdrawn |
| Chlorpromazine | The risk or severity of adverse effects can be increased when Chlorpromazine is combined with Butorphanol. | Approved, Vet Approved |
| Chlorprothixene | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chlorprothixene. | Approved, Withdrawn |
| Chlorthalidone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chlorthalidone. | Approved |
| Chlorzoxazone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Chlorzoxazone. | Approved |
| Cicletanine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Cicletanine. | Investigational |
| Cinchocaine | The risk or severity of adverse effects can be increased when Cinchocaine is combined with Butorphanol. | Approved, Vet Approved |
| Citalopram | Butorphanol may increase the serotonergic activities of Citalopram. | Approved |
| Clemastine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Clemastine. | Approved |
| Clidinium | The risk or severity of adverse effects can be increased when Butorphanol is combined with Clidinium. | Approved |
| Clobazam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Clobazam. | Approved, Illicit |
| Clomipramine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Clomipramine. | Approved, Vet Approved |
| Clonazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Clonazepam. | Approved, Illicit |
| Clonidine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Clonidine. | Approved |
| Clorazepate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Clorazepate. | Approved, Illicit |
| Clozapine | The risk or severity of adverse effects can be increased when Clozapine is combined with Butorphanol. | Approved |
| Cocaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Cocaine. | Approved, Illicit |
| Codeine | Butorphanol may decrease the analgesic activities of Codeine. | Approved, Illicit |
| Conivaptan | The risk or severity of adverse effects can be increased when Butorphanol is combined with Conivaptan. | Approved, Investigational |
| Cyclizine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Cyclizine. | Approved |
| Cyclobenzaprine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Cyclobenzaprine. | Approved |
| Cyclopentolate | The risk or severity of adverse effects can be increased when Cyclopentolate is combined with Butorphanol. | Approved |
| Cyclothiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Cyclothiazide. | Approved |
| Cyproheptadine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Cyproheptadine. | Approved |
| Dantrolene | The risk or severity of adverse effects can be increased when Butorphanol is combined with Dantrolene. | Approved |
| Dapiprazole | The risk or severity of adverse effects can be increased when Dapiprazole is combined with Butorphanol. | Approved |
| Dapoxetine | Butorphanol may increase the serotonergic activities of Dapoxetine. | Investigational |
| Darifenacin | The risk or severity of adverse effects can be increased when Darifenacin is combined with Butorphanol. | Approved, Investigational |
| Deramciclane | The risk or severity of adverse effects can be increased when Butorphanol is combined with deramciclane. | Investigational |
| Desflurane | The risk or severity of adverse effects can be increased when Butorphanol is combined with Desflurane. | Approved |
| Desipramine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Desipramine. | Approved |
| Desloratadine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Desloratadine. | Approved, Investigational |
| Desmopressin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Desmopressin. | Approved |
| Desvenlafaxine | Butorphanol may increase the serotonergic activities of Desvenlafaxine. | Approved |
| Dexbrompheniramine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Dexbrompheniramine. | Approved |
| Dexetimide | The risk or severity of adverse effects can be increased when Dexetimide is combined with Butorphanol. | Withdrawn |
| Dexmedetomidine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Dexmedetomidine. | Approved, Vet Approved |
| Dextroamphetamine | Dextroamphetamine may increase the analgesic activities of Butorphanol. | Approved, Illicit |
| Dextromoramide | Butorphanol may decrease the analgesic activities of Dextromoramide. | Experimental, Illicit |
| Dextropropoxyphene | Butorphanol may decrease the analgesic activities of Dextropropoxyphene. | Approved, Illicit, Withdrawn |
| Dezocine | Butorphanol may decrease the analgesic activities of Dezocine. | Approved |
| Diazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Diazepam. | Approved, Illicit, Vet Approved |
| Dicyclomine | The risk or severity of adverse effects can be increased when Dicyclomine is combined with Butorphanol. | Approved |
| Diethylpropion | Diethylpropion may increase the analgesic activities of Butorphanol. | Approved, Illicit |
| Difenoxin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Difenoxin. | Approved, Illicit |
| Dihydrocodeine | Butorphanol may decrease the analgesic activities of Dihydrocodeine. | Approved, Illicit |
| Dihydroetorphine | Butorphanol may decrease the analgesic activities of Dihydroetorphine. | Experimental, Illicit |
| Dihydromorphine | Butorphanol may decrease the analgesic activities of Dihydromorphine. | Experimental, Illicit |
| Dimenhydrinate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Dimenhydrinate. | Approved |
| Diphenhydramine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Diphenhydramine. | Approved |
| Diphenoxylate | Butorphanol may decrease the analgesic activities of Diphenoxylate. | Approved, Illicit |
| Doxepin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Doxepin. | Approved |
| Doxylamine | Doxylamine may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved, Vet Approved |
| Dronabinol | Dronabinol may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved, Illicit |
| Droperidol | Droperidol may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved, Vet Approved |
| Drospirenone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Drospirenone. | Approved |
| Drotebanol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Drotebanol. | Experimental, Illicit |
| Duloxetine | Butorphanol may increase the serotonergic activities of Duloxetine. | Approved |
| Dyclonine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Dyclonine. | Approved |
| Ecgonine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ecgonine. | Experimental, Illicit |
| Ecopipam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ecopipam. | Investigational |
| Efavirenz | The risk or severity of adverse effects can be increased when Butorphanol is combined with Efavirenz. | Approved, Investigational |
| Efonidipine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Efonidipine. | Approved |
| Eltanolone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Pregnanolone. | Investigational |
| Eluxadoline | Butorphanol may increase the constipating activities of Eluxadoline. | Approved |
| Enflurane | The risk or severity of adverse effects can be increased when Enflurane is combined with Butorphanol. | Approved, Vet Approved |
| Entacapone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Entacapone. | Approved, Investigational |
| Eplerenone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Eplerenone. | Approved |
| Escitalopram | Butorphanol may increase the serotonergic activities of Escitalopram. | Approved, Investigational |
| Estazolam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Estazolam. | Approved, Illicit |
| Eszopiclone | The risk or severity of adverse effects can be increased when Eszopiclone is combined with Butorphanol. | Approved |
| Etacrynic acid | The risk or severity of adverse effects can be increased when Butorphanol is combined with Etacrynic acid. | Approved |
| Ethanol | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Ethanol. | Approved |
| Ethchlorvynol | The risk or severity of adverse effects can be increased when Ethchlorvynol is combined with Butorphanol. | Approved, Illicit, Withdrawn |
| Ethopropazine | The risk or severity of adverse effects can be increased when Ethopropazine is combined with Butorphanol. | Approved |
| Ethosuximide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ethosuximide. | Approved |
| Ethotoin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ethotoin. | Approved |
| Ethoxzolamide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ethoxzolamide. | Withdrawn |
| Ethyl carbamate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ethyl carbamate. | Withdrawn |
| Ethyl loflazepate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ethyl loflazepate. | Approved, Illicit |
| Ethylmorphine | Butorphanol may decrease the analgesic activities of Ethylmorphine. | Approved, Illicit |
| Etidocaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Etidocaine. | Approved |
| Etifoxine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Etifoxine. | Withdrawn |
| Etizolam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Etizolam. | Approved |
| Etomidate | The risk or severity of adverse effects can be increased when Etomidate is combined with Butorphanol. | Approved |
| Etoperidone | Butorphanol may increase the serotonergic activities of Etoperidone. | Approved |
| Etorphine | Butorphanol may decrease the analgesic activities of Etorphine. | Illicit, Vet Approved |
| Ezogabine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ezogabine. | Approved |
| Felbamate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Felbamate. | Approved |
| Fencamfamine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fencamfamine. | Approved, Illicit, Withdrawn |
| Fentanyl | Butorphanol may decrease the analgesic activities of Fentanyl. | Approved, Illicit, Investigational, Vet Approved |
| Fesoterodine | The risk or severity of adverse effects can be increased when Fesoterodine is combined with Butorphanol. | Approved |
| Fexofenadine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fexofenadine. | Approved |
| Flibanserin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Flibanserin. | Approved |
| Fludiazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fludiazepam. | Approved, Illicit |
| Flunarizine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Flunarizine. | Approved |
| Flunitrazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Flunitrazepam. | Approved, Illicit |
| Fluoxetine | Butorphanol may increase the serotonergic activities of Fluoxetine. | Approved, Vet Approved |
| Flupentixol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Flupentixol. | Approved, Withdrawn |
| Fluphenazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fluphenazine. | Approved |
| Flurazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Flurazepam. | Approved, Illicit |
| Fluspirilene | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fluspirilene. | Approved |
| Fluticasone propionate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fluticasone Propionate. | Approved |
| Fluvoxamine | The risk or severity of adverse effects can be increased when Fluvoxamine is combined with Butorphanol. | Approved, Investigational |
| Fosphenytoin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fosphenytoin. | Approved |
| Fospropofol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Fospropofol. | Approved, Illicit |
| Furosemide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Furosemide. | Approved, Vet Approved |
| Gabapentin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Gabapentin. | Approved, Investigational |
| Gabapentin Enacarbil | The risk or severity of adverse effects can be increased when Butorphanol is combined with gabapentin enacarbil. | Approved |
| Gallamine Triethiodide | The risk or severity of adverse effects can be increased when Gallamine Triethiodide is combined with Butorphanol. | Approved |
| Gamma Hydroxybutyric Acid | The risk or severity of adverse effects can be increased when Butorphanol is combined with Gamma Hydroxybutyric Acid. | Approved, Illicit |
| Gepirone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Gepirone. | Investigational |
| Glutethimide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Glutethimide. | Approved, Illicit |
| Glycopyrronium | The risk or severity of adverse effects can be increased when Glycopyrronium is combined with Butorphanol. | Approved, Investigational, Vet Approved |
| Guanfacine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Guanfacine. | Approved, Investigational |
| Halazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Halazepam. | Approved, Illicit, Withdrawn |
| Haloperidol | The risk or severity of adverse effects can be increased when Haloperidol is combined with Butorphanol. | Approved |
| Halothane | The risk or severity of adverse effects can be increased when Butorphanol is combined with Halothane. | Approved, Vet Approved |
| Heroin | Butorphanol may decrease the analgesic activities of Heroin. | Approved, Illicit |
| Hexamethonium | The risk or severity of adverse effects can be increased when Hexamethonium is combined with Butorphanol. | Experimental |
| Hexobarbital | The risk or severity of adverse effects can be increased when Butorphanol is combined with Hexobarbital. | Approved |
| Hydrochlorothiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Hydrochlorothiazide. | Approved, Vet Approved |
| Hydrocodone | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Hydrocodone. | Approved, Illicit |
| Hydroflumethiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Hydroflumethiazide. | Approved |
| Hydromorphone | Butorphanol may decrease the analgesic activities of Hydromorphone. | Approved, Illicit |
| Hydroxyamphetamine | Hydroxyamphetamine hydrobromide may increase the analgesic activities of Butorphanol. | Approved |
| Hydroxyzine | Hydroxyzine may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved |
| Hyoscyamine | The risk or severity of adverse effects can be increased when Hyoscyamine is combined with Butorphanol. | Approved |
| Iloperidone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Iloperidone. | Approved |
| Imipramine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Imipramine. | Approved |
| Indalpine | Butorphanol may increase the serotonergic activities of Indalpine. | Investigational, Withdrawn |
| Indapamide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Indapamide. | Approved |
| Ipratropium bromide | The risk or severity of adverse effects can be increased when Ipratropium bromide is combined with Butorphanol. | Approved |
| Isoflurane | The risk or severity of adverse effects can be increased when Butorphanol is combined with Isoflurane. | Approved, Vet Approved |
| Ketamine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ketamine. | Approved, Vet Approved |
| Ketazolam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ketazolam. | Approved |
| Ketobemidone | Butorphanol may decrease the analgesic activities of Ketobemidone. | Approved |
| Lamotrigine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Lamotrigine. | Approved, Investigational |
| Levetiracetam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Levetiracetam. | Approved, Investigational |
| Levobupivacaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Levobupivacaine. | Approved |
| Levocabastine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Levocabastine. | Approved |
| Levocetirizine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Levocetirizine. | Approved |
| Levodopa | The risk or severity of adverse effects can be increased when Butorphanol is combined with Levodopa. | Approved |
| Levomethadyl Acetate | Butorphanol may decrease the analgesic activities of Levomethadyl Acetate. | Approved |
| Levomilnacipran | Butorphanol may increase the serotonergic activities of Levomilnacipran. | Approved |
| Levorphanol | Butorphanol may decrease the analgesic activities of Levorphanol. | Approved |
| Lidocaine | The risk or severity of adverse effects can be increased when Lidocaine is combined with Butorphanol. | Approved, Vet Approved |
| Lisdexamfetamine | Lisdexamfetamine may increase the analgesic activities of Butorphanol. | Approved, Investigational |
| Lithium | The risk or severity of adverse effects can be increased when Butorphanol is combined with Lithium. | Approved |
| Lofentanil | Butorphanol may decrease the analgesic activities of Lofentanil. | Illicit |
| Loratadine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Loratadine. | Approved |
| Lorazepam | The risk or severity of adverse effects can be increased when Lorazepam is combined with Butorphanol. | Approved |
| Loxapine | The risk or severity of adverse effects can be increased when Loxapine is combined with Butorphanol. | Approved |
| Lurasidone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Lurasidone. | Approved |
| Magnesium Sulfate | Magnesium Sulfate may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved, Vet Approved |
| Mannitol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Mannitol. | Approved, Investigational |
| Maprotiline | The risk or severity of adverse effects can be increased when Butorphanol is combined with Maprotiline. | Approved |
| Mecamylamine | The risk or severity of adverse effects can be increased when Mecamylamine is combined with Butorphanol. | Approved |
| Meclizine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Meclizine. | Approved |
| Melatonin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Melatonin. | Approved, Nutraceutical, Vet Approved |
| Melperone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Melperone. | Approved |
| Mephedrone | Mephedrone may increase the analgesic activities of Butorphanol. | Investigational |
| Mephentermine | Mephentermine may increase the analgesic activities of Butorphanol. | Approved |
| Mepivacaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Mepivacaine. | Approved, Vet Approved |
| Meprobamate | The risk or severity of adverse effects can be increased when Meprobamate is combined with Butorphanol. | Approved, Illicit |
| Mersalyl | The risk or severity of adverse effects can be increased when Butorphanol is combined with Mersalyl. | Approved |
| Mesoridazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Mesoridazine. | Approved |
| Metaxalone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Metaxalone. | Approved |
| Methadone | Butorphanol may decrease the analgesic activities of Methadone. | Approved |
| Methadyl Acetate | Butorphanol may decrease the analgesic activities of Methadyl Acetate. | Approved, Illicit |
| Methamphetamine | Methamphetamine may increase the analgesic activities of Butorphanol. | Approved, Illicit |
| Methantheline | The risk or severity of adverse effects can be increased when Methantheline is combined with Butorphanol. | Approved |
| Methapyrilene | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methapyrilene. | Withdrawn |
| Methaqualone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methaqualone. | Illicit, Withdrawn |
| Methazolamide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methazolamide. | Approved |
| Methocarbamol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methocarbamol. | Approved, Vet Approved |
| Methohexital | The risk or severity of adverse effects can be increased when Methohexital is combined with Butorphanol. | Approved |
| Methotrimeprazine | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Methotrimeprazine. | Approved |
| Methoxyflurane | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methoxyflurane. | Approved, Vet Approved |
| Methsuximide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methsuximide. | Approved |
| Methyclothiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methyclothiazide. | Approved |
| Methylecgonine | The risk or severity of adverse effects can be increased when Butorphanol is combined with ECGONINE METHYL ESTER. | Experimental |
| Methylene blue | Methylene blue may increase the hypotensive activities of Butorphanol. | Investigational |
| Methylnaltrexone | The risk or severity of adverse effects can be increased when Methylnaltrexone is combined with Butorphanol. | Approved |
| Methylphenobarbital | The risk or severity of adverse effects can be increased when Butorphanol is combined with Methylphenobarbital. | Approved |
| Metixene | The risk or severity of adverse effects can be increased when Metixene is combined with Butorphanol. | Approved |
| Metolazone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Metolazone. | Approved |
| Metyrosine | Butorphanol may increase the sedative activities of Metyrosine. | Approved |
| Midazolam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Midazolam. | Approved, Illicit |
| Milnacipran | Butorphanol may increase the serotonergic activities of Milnacipran. | Approved |
| Minocycline | Minocycline may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved, Investigational |
| Mirtazapine | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Mirtazapine. | Approved |
| MMDA | MMDA may increase the analgesic activities of Butorphanol. | Experimental, Illicit |
| Molindone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Molindone. | Approved |
| Moricizine | Moricizine may increase the hypotensive activities of Butorphanol. | Approved, Withdrawn |
| Morphine | Butorphanol may decrease the analgesic activities of Morphine. | Approved, Investigational |
| Nabilone | Nabilone may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved, Investigational |
| Nalbuphine | Butorphanol may decrease the analgesic activities of Nalbuphine. | Approved |
| Naloxegol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Naloxegol. | Approved |
| Naltrexone | The therapeutic efficacy of Butorphanol can be decreased when used in combination with Naltrexone. | Approved, Investigational, Vet Approved |
| Nefazodone | Butorphanol may increase the serotonergic activities of Nefazodone. | Approved, Withdrawn |
| Nitrazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Nitrazepam. | Approved |
| Nitrous oxide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Nitrous oxide. | Approved, Vet Approved |
| Norflurane | The risk or severity of adverse effects can be increased when Butorphanol is combined with 1,1,1,2 Tetrafluoroethane. | Investigational |
| Normethadone | Butorphanol may decrease the analgesic activities of Normethadone. | Approved, Illicit |
| Nortriptyline | The risk or severity of adverse effects can be increased when Butorphanol is combined with Nortriptyline. | Approved |
| Olanzapine | The risk or severity of adverse effects can be increased when Olanzapine is combined with Butorphanol. | Approved, Investigational |
| Olopatadine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Olopatadine. | Approved |
| Ondansetron | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ondansetron. | Approved |
| Opium | Butorphanol may decrease the analgesic activities of Opium. | Approved, Illicit |
| Orphenadrine | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Orphenadrine. | Approved |
| Osanetant | The risk or severity of adverse effects can be increased when Butorphanol is combined with Osanetant. | Investigational |
| Oxazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Oxazepam. | Approved |
| Oxethazaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Oxetacaine. | Investigational |
| Oxprenolol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Oxprenolol. | Approved |
| Oxybuprocaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Oxybuprocaine. | Approved |
| Oxybutynin | The risk or severity of adverse effects can be increased when Oxybutynin is combined with Butorphanol. | Approved, Investigational |
| Oxycodone | Butorphanol may decrease the analgesic activities of Oxycodone. | Approved, Illicit, Investigational |
| Oxymorphone | Butorphanol may decrease the analgesic activities of Oxymorphone. | Approved, Investigational, Vet Approved |
| Oxyphenonium | The risk or severity of adverse effects can be increased when Oxyphenonium is combined with Butorphanol. | Approved |
| Paliperidone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Paliperidone. | Approved |
| Pancuronium | The risk or severity of adverse effects can be increased when Pancuronium is combined with Butorphanol. | Approved |
| Paraldehyde | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Paraldehyde. | Approved |
| Paroxetine | Butorphanol may increase the serotonergic activities of Paroxetine. | Approved, Investigational |
| Pegvisomant | The therapeutic efficacy of Pegvisomant can be decreased when used in combination with Butorphanol. | Approved |
| Pentazocine | Butorphanol may decrease the analgesic activities of Pentazocine. | Approved, Vet Approved |
| Pentobarbital | The risk or severity of adverse effects can be increased when Pentobarbital is combined with Butorphanol. | Approved, Vet Approved |
| Pentolinium | The risk or severity of adverse effects can be increased when Pentolinium is combined with Butorphanol. | Approved |
| Perampanel | Perampanel may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved |
| Perazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Perazine. | Investigational |
| Perospirone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Perospirone. | Approved |
| Perphenazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Perphenazine. | Approved |
| Pethidine | Butorphanol may decrease the analgesic activities of Pethidine. | Approved |
| Phenobarbital | The risk or severity of adverse effects can be increased when Butorphanol is combined with Phenobarbital. | Approved |
| Phentermine | Phentermine may increase the analgesic activities of Butorphanol. | Approved, Illicit |
| Phenytoin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Phenytoin. | Approved, Vet Approved |
| Pimozide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Pimozide. | Approved |
| Pipamperone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Pipamperone. | Approved |
| Pipecuronium | The risk or severity of adverse effects can be increased when Pipecuronium is combined with Butorphanol. | Approved |
| Pipotiazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Pipotiazine. | Approved |
| Pirenzepine | The risk or severity of adverse effects can be increased when Pirenzepine is combined with Butorphanol. | Approved |
| Piretanide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Piretanide. | Experimental |
| Piritramide | Butorphanol may decrease the analgesic activities of Piritramide. | Investigational |
| Polythiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Polythiazide. | Approved |
| Pomalidomide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Pomalidomide. | Approved |
| Potassium | The risk or severity of adverse effects can be increased when Butorphanol is combined with Potassium. | Approved |
| Potassium Citrate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Potassium Citrate. | Approved, Vet Approved |
| Pramipexole | Butorphanol may increase the sedative activities of Pramipexole. | Approved, Investigational |
| Pramocaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Pramocaine. | Approved |
| Prazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Prazepam. | Approved, Illicit |
| Pregabalin | The risk or severity of adverse effects can be increased when Pregabalin is combined with Butorphanol. | Approved, Illicit, Investigational |
| Prilocaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Prilocaine. | Approved |
| Primidone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Primidone. | Approved, Vet Approved |
| Procaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Procaine. | Approved, Investigational, Vet Approved |
| Prochlorperazine | The risk or severity of adverse effects can be increased when Prochlorperazine is combined with Butorphanol. | Approved, Vet Approved |
| Procyclidine | The risk or severity of adverse effects can be increased when Procyclidine is combined with Butorphanol. | Approved |
| Promazine | The risk or severity of adverse effects can be increased when Promazine is combined with Butorphanol. | Approved, Vet Approved |
| Promethazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Promethazine. | Approved |
| Propantheline | The risk or severity of adverse effects can be increased when Propantheline is combined with Butorphanol. | Approved |
| Proparacaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Proparacaine. | Approved, Vet Approved |
| Propiverine | The risk or severity of adverse effects can be increased when Propiverine is combined with Butorphanol. | Investigational |
| Propofol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Propofol. | Approved, Investigational, Vet Approved |
| Propoxycaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Propoxycaine. | Approved |
| Protriptyline | The risk or severity of adverse effects can be increased when Butorphanol is combined with Protriptyline. | Approved |
| Pseudoephedrine | Pseudoephedrine may increase the analgesic activities of Butorphanol. | Approved |
| Quazepam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Quazepam. | Approved, Illicit |
| Quetiapine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Quetiapine. | Approved |
| Quinethazone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Quinethazone. | Approved |
| Quinidine | The risk or severity of adverse effects can be increased when Quinidine is combined with Butorphanol. | Approved |
| Raclopride | The risk or severity of adverse effects can be increased when Butorphanol is combined with Raclopride. | Investigational |
| Ramelteon | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ramelteon. | Approved, Investigational |
| Ramosetron | Butorphanol may increase the constipating activities of Ramosetron. | Approved |
| Remifentanil | Butorphanol may decrease the analgesic activities of Remifentanil. | Approved |
| Remoxipride | The risk or severity of adverse effects can be increased when Remoxipride is combined with Butorphanol. | Approved, Withdrawn |
| Reserpine | The risk or severity of adverse effects can be increased when Reserpine is combined with Butorphanol. | Approved |
| Risperidone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Risperidone. | Approved, Investigational |
| Ritanserin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ritanserin. | Investigational |
| Ritobegron | Ritobegron may increase the analgesic activities of Butorphanol. | Investigational |
| Rolofylline | The risk or severity of adverse effects can be increased when Butorphanol is combined with Rolofylline. | Investigational |
| Ropinirole | Butorphanol may increase the sedative activities of Ropinirole. | Approved, Investigational |
| Ropivacaine | The risk or severity of adverse effects can be increased when Ropivacaine is combined with Butorphanol. | Approved |
| Rotigotine | Butorphanol may increase the sedative activities of Rotigotine. | Approved |
| Rufinamide | The risk or severity of adverse effects can be increased when Rufinamide is combined with Butorphanol. | Approved |
| Scopolamine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Scopolamine. | Approved |
| Scopolamine butylbromide | The risk or severity of adverse effects can be increased when Scopolamine butylbromide is combined with Butorphanol. | Approved, Vet Approved |
| Secobarbital | The risk or severity of adverse effects can be increased when Secobarbital is combined with Butorphanol. | Approved, Vet Approved |
| Sepranolone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Uc1010. | Investigational |
| Sertindole | The risk or severity of adverse effects can be increased when Butorphanol is combined with Sertindole. | Approved, Withdrawn |
| Sertraline | Butorphanol may increase the serotonergic activities of Sertraline. | Approved |
| Sevoflurane | The risk or severity of adverse effects can be increased when Butorphanol is combined with Sevoflurane. | Approved, Vet Approved |
| Sodium oxybate | Sodium oxybate may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved |
| Solifenacin | The risk or severity of adverse effects can be increased when Solifenacin is combined with Butorphanol. | Approved |
| Spironolactone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Spironolactone. | Approved |
| Stiripentol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Stiripentol. | Approved |
| Succinylcholine | Succinylcholine may increase the bradycardic activities of Butorphanol. | Approved |
| Sufentanil | Butorphanol may decrease the analgesic activities of Sufentanil. | Approved, Investigational |
| Sulpiride | The risk or severity of adverse effects can be increased when Sulpiride is combined with Butorphanol. | Approved |
| Suvorexant | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Suvorexant. | Approved |
| Tandospirone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tandospirone. | Investigational |
| Tapentadol | Tapentadol may increase the central nervous system depressant (CNS depressant) activities of Butorphanol. | Approved |
| Tasimelteon | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tasimelteon. | Approved |
| Temazepam | The risk or severity of adverse effects can be increased when Temazepam is combined with Butorphanol. | Approved |
| Tetrabenazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tetrabenazine. | Approved |
| Tetracaine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tetracaine. | Approved, Vet Approved |
| Tetrodotoxin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tetrodotoxin. | Investigational |
| Thalidomide | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Thalidomide. | Approved, Investigational, Withdrawn |
| Theobromine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Theobromine. | Approved |
| Thiamylal | The risk or severity of adverse effects can be increased when Butorphanol is combined with Thiamylal. | Approved, Vet Approved |
| Thiethylperazine | Thiethylperazine may increase the hypotensive activities of Butorphanol. | Withdrawn |
| Thiopental | The risk or severity of adverse effects can be increased when Thiopental is combined with Butorphanol. | Approved, Vet Approved |
| Thioridazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Thioridazine. | Withdrawn |
| Thiothixene | The risk or severity of adverse effects can be increased when Butorphanol is combined with Thiothixene. | Approved |
| Tiagabine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tiagabine. | Approved |
| Tiapride | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tiapride. | Approved, Investigational |
| Ticrynafen | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ticrynafen. | Withdrawn |
| Tiotropium | The risk or severity of adverse effects can be increased when Tiotropium is combined with Butorphanol. | Approved |
| Tizanidine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tizanidine. | Approved |
| Tolcapone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tolcapone. | Approved, Withdrawn |
| Tolterodine | The risk or severity of adverse effects can be increased when Tolterodine is combined with Butorphanol. | Approved, Investigational |
| Tolvaptan | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tolvaptan. | Approved |
| Topiramate | The risk or severity of adverse effects can be increased when Butorphanol is combined with Topiramate. | Approved |
| Torasemide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Torasemide. | Approved |
| Tramadol | Butorphanol may decrease the analgesic activities of Tramadol. | Approved, Investigational |
| Trans-2-Phenylcyclopropylamine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Trans-2-Phenylcyclopropylamine. | Experimental |
| Tranylcypromine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Tranylcypromine. | Approved |
| Trazodone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Trazodone. | Approved, Investigational |
| Triamterene | The risk or severity of adverse effects can be increased when Butorphanol is combined with Triamterene. | Approved |
| Triazolam | The risk or severity of adverse effects can be increased when Butorphanol is combined with Triazolam. | Approved |
| Trichlormethiazide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Trichlormethiazide. | Approved, Vet Approved |
| Trifluoperazine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Trifluoperazine. | Approved |
| Triflupromazine | The risk or severity of adverse effects can be increased when Triflupromazine is combined with Butorphanol. | Approved, Vet Approved |
| Trihexyphenidyl | The risk or severity of adverse effects can be increased when Trihexyphenidyl is combined with Butorphanol. | Approved |
| Trimethaphan | The risk or severity of adverse effects can be increased when Trimethaphan is combined with Butorphanol. | Approved |
| Trimipramine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Trimipramine. | Approved |
| Triprolidine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Triprolidine. | Approved |
| Tropicamide | The risk or severity of adverse effects can be increased when Tropicamide is combined with Butorphanol. | Approved |
| Trospium | The risk or severity of adverse effects can be increased when Trospium is combined with Butorphanol. | Approved |
| Tubocurarine | The risk or severity of adverse effects can be increased when Tubocurarine is combined with Butorphanol. | Approved |
| Ularitide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ularitide. | Investigational |
| Umeclidinium | The risk or severity of adverse effects can be increased when Umeclidinium is combined with Butorphanol. | Approved |
| Valproic Acid | The risk or severity of adverse effects can be increased when Valproic Acid is combined with Butorphanol. | Approved, Investigational |
| Vecuronium | The risk or severity of adverse effects can be increased when Vecuronium is combined with Butorphanol. | Approved |
| Venlafaxine | Butorphanol may increase the serotonergic activities of Venlafaxine. | Approved |
| Vigabatrin | The risk or severity of adverse effects can be increased when Butorphanol is combined with Vigabatrin. | Approved |
| Vortioxetine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Vortioxetine. | Approved |
| Zaleplon | The risk or severity of adverse effects can be increased when Butorphanol is combined with Zaleplon. | Approved, Illicit, Investigational |
| Ziconotide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Ziconotide. | Approved |
| Zimelidine | Butorphanol may increase the serotonergic activities of Zimelidine. | Withdrawn |
| Ziprasidone | The risk or severity of adverse effects can be increased when Ziprasidone is combined with Butorphanol. | Approved |
| Zolpidem | Butorphanol may increase the central nervous system depressant (CNS depressant) activities of Zolpidem. | Approved |
| Zonisamide | The risk or severity of adverse effects can be increased when Butorphanol is combined with Zonisamide. | Approved, Investigational |
| Zopiclone | The risk or severity of adverse effects can be increased when Butorphanol is combined with Zopiclone. | Approved |
| Zotepine | The risk or severity of adverse effects can be increased when Butorphanol is combined with Zotepine. | Approved |
| Zuclopenthixol | The risk or severity of adverse effects can be increased when Butorphanol is combined with Zuclopenthixol. | Approved, Investigational |
