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Identification
NamePrazosin
Accession NumberDB00457  (APRD00020)
TypeSmall Molecule
GroupsApproved
Description

Prazosin is a selective α-1-adrenergic receptor antagonist used to treat hypertension. It has also been used to decrease urinary obstruction and relieve symptoms associated with symptomatic benign prostatic hyperplasia. α1-Receptors mediate contraction and hypertrophic growth of smooth muscle cells. Antagonism of these receptors leads to smooth muscle relaxation in the peripheral vasculature and prostate gland. Prazosin has also been used in conjunction with cardiac glycosides and diuretics in the management of severe congestive heart failure. It has also been used alone or in combination with β-blockers in the preoperative management of signs and symptoms of pheochromocytoma.

Structure
Thumb
Synonyms
1-(4-Amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)piperazine
2-(4-(2-Furoyl)piperazin-1-yl)-4-amino-6,7-dimethoxyquinazoline
Prazosina
Prazosine
Prazosinum
External Identifiers Not Available
Approved Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Alti-prazosin-tab 1mgtablet1 mgoralAltimed Pharma Inc.1995-12-312005-05-27Canada
Alti-prazosin-tab 2mgtablet2 mgoralAltimed Pharma Inc.1995-12-312005-05-27Canada
Alti-prazosin-tab 5mgtablet5 mgoralAltimed Pharma Inc.1995-12-312005-05-27Canada
Minipresscapsule1 mg/1oralPfizer Laboratories Div Pfizer Inc1994-05-10Not applicableUs
Minipresstablet5 mgoralErfa Canada 2012 Inc1983-12-31Not applicableCanada
Minipresscapsule5 mg/1oralPfizer Laboratories Div Pfizer Inc1994-05-10Not applicableUs
Minipresstablet2 mgoralErfa Canada 2012 Inc1983-12-31Not applicableCanada
Minipresscapsule2 mg/1oralPfizer Laboratories Div Pfizer Inc1994-05-10Not applicableUs
Minipresstablet1 mgoralErfa Canada 2012 Inc1983-12-31Not applicableCanada
Nu-prazo Tab 1mgtablet1 mgoralNu Pharm Inc1992-12-312012-09-04Canada
Nu-prazo Tab 2mgtablet2 mgoralNu Pharm Inc1992-12-312012-09-04Canada
Nu-prazo Tab 5mgtablet5 mgoralNu Pharm Inc1992-12-312012-09-04Canada
Prazosin-1 Tab 1mgtablet1 mgoralPro Doc Limitee1991-12-312009-07-23Canada
Prazosin-2 Tab 2mgtablet2 mgoralPro Doc Limitee1991-12-312009-07-23Canada
Prazosin-5 Tabtablet5 mgoralPro Doc Limitee1991-12-312009-07-23Canada
Rho-prazosin - Tab 1mgtablet1 mgoralRhodiapharm Inc1995-12-311998-08-05Canada
Rho-prazosin - Tab 5mgtablet5 mgoralRhodiapharm Inc1995-12-311998-08-05Canada
Rho-prazosin-tab 2mgtablet2 mgoralRhodiapharm Inc1995-12-311998-08-05Canada
Teva-prazosintablet5 mgoralTeva Canada Limited1992-12-31Not applicableCanada
Teva-prazosintablet2 mgoralTeva Canada Limited1992-12-31Not applicableCanada
Teva-prazosintablet1 mgoralTeva Canada Limited1992-12-31Not applicableCanada
Approved Generic Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Apo-prazo Tab 1mgtablet1 mgoralApotex Inc1990-12-31Not applicableCanada
Apo-prazo Tab 2mgtablet2 mgoralApotex Inc1990-12-31Not applicableCanada
Apo-prazo Tab 5mgtablet5 mgoralApotex Inc1990-12-31Not applicableCanada
Prazosin Hydrochloridecapsule5 mg/1oralREMEDYREPACK INC.2011-04-21Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralTeva Pharmaceuticals USA Inc2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralMylan Institutional Inc.1998-10-05Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralAidarex Pharmaceuticals LLC2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralPhysicians Total Care, Inc.2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralCarilion Materials Management2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralREMEDYREPACK INC.2010-10-11Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralState of Florida DOH Central Pharmacy2014-11-01Not applicableUs
Prazosin Hydrochloridecapsule5 mg/1oralMylan Pharmaceuticals Inc.1989-02-28Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralAphena Pharma Solutions Tennessee, Llc2013-05-17Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralAmerican Health Packaging2015-03-31Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralCardinal Health1998-10-05Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralREMEDYREPACK INC.2013-05-28Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralMylan Pharmaceuticals Inc.1989-02-28Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralAphena Pharma Solutions Tennessee, Inc.2009-12-21Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralAmerican Health Packaging2015-03-31Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralMylan Pharmaceuticals Inc.1989-02-28Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralA S Medication Solutions2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralREMEDYREPACK INC.2013-05-28Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralPd Rx Pharmaceuticals, Inc.2010-02-10Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralTYA Pharmaceuticals2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule5 mg/1oralTeva Pharmaceuticals USA Inc2007-01-18Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralA S Medication Solutions2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule5 mg/1oralMylan Institutional Inc.1998-10-06Not applicableUs
Prazosin Hydrochloridecapsule5 mg/1oralPd Rx Pharmaceuticals, Inc.2010-02-10Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralbryant ranch prepack2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralREMEDYREPACK INC.2011-11-30Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralTeva Pharmaceuticals USA Inc2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule5 mg/1oralREMEDYREPACK INC.2016-01-22Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralMylan Institutional Inc.1998-10-06Not applicableUs
Prazosin Hydrochloridecapsule2 mg/1oralAidarex Pharmaceuticals LLC2007-02-22Not applicableUs
Prazosin Hydrochloridecapsule1 mg/1oralLake Erie Medical DBA Quality Care Products LLC1989-02-28Not applicableUs
Approved Over the Counter ProductsNot Available
Unapproved/Other Products Not Available
International Brands
NameCompany
HypovaseNot Available
Minipress XlPfizer
PressinNot Available
VasoflexNot Available
Brand mixturesNot Available
Salts
Name/CASStructureProperties
Prazosin Hydrochloride
19237-84-4
Thumb
  • InChI Key: WFXFYZULCQKPIP-UHFFFAOYSA-N
  • Monoisotopic Mass: 419.136031924
  • Average Mass: 419.862
DBSALT000329
Categories
UNIIXM03YJ541D
CAS number19216-56-9
WeightAverage: 383.4011
Monoisotopic: 383.159354185
Chemical FormulaC19H21N5O4
InChI KeyInChIKey=IENZQIKPVFGBNW-UHFFFAOYSA-N
InChI
InChI=1S/C19H21N5O4/c1-26-15-10-12-13(11-16(15)27-2)21-19(22-17(12)20)24-7-5-23(6-8-24)18(25)14-4-3-9-28-14/h3-4,9-11H,5-8H2,1-2H3,(H2,20,21,22)
IUPAC Name
2-[4-(furan-2-carbonyl)piperazin-1-yl]-6,7-dimethoxyquinazolin-4-amine
SMILES
COC1=C(OC)C=C2C(N)=NC(=NC2=C1)N1CCN(CC1)C(=O)C1=CC=CO1
Taxonomy
DescriptionThis compound belongs to the class of organic compounds known as n-arylpiperazines. These are organic compounds containing a piperazine ring where the nitrogen ring atom carries an aryl group.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassDiazinanes
Sub ClassPiperazines
Direct ParentN-arylpiperazines
Alternative Parents
Substituents
  • N-arylpiperazine
  • Quinazolinamine
  • Quinazoline
  • Dialkylarylamine
  • Anisole
  • Aminopyrimidine
  • Alkyl aryl ether
  • Imidolactam
  • Benzenoid
  • Pyrimidine
  • Primary aromatic amine
  • Heteroaromatic compound
  • Furan
  • Tertiary amine
  • Carboxamide group
  • Oxacycle
  • Azacycle
  • Ether
  • Carboxylic acid derivative
  • Hydrocarbon derivative
  • Primary amine
  • Organooxygen compound
  • Organonitrogen compound
  • Carbonyl group
  • Amine
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External Descriptors
Pharmacology
IndicationFor treatment of hypertension, symptomatic benign prostatic hyperplasia, and severe congestive heart failure. May also be used alone or in combination with β-blockers in the preoperative management of signs and symptoms of pheochromocytoma.
PharmacodynamicsPrazosin is an alpha-adrenergic blocking agent used to treat hypertension and benign prostatic hyperplasia. Accordingly, Prazosin is a selective inhibitor of the alpha1 subtype of alpha adrenergic receptors. In the human prostate, Prazosin antagonizes phenylephrine (alpha1 agonist)-induced contractions, in vitro, and binds with high affinity to the alpha1c adrenoceptor, which is thought to be the predominant functional type in the prostate. Studies in normal human subjects have shown that Prazosin competitively antagonized the pressor effects of phenylephrine (an alpha1 agonist) and the systolic pressor effect of norepinephrine. The antihypertensive effect of Prazosin results from a decrease in systemic vascular resistance and the parent compound Prazosin is primarily responsible for the antihypertensive activity.
Mechanism of actionPrazosin acts by inhibiting the postsynaptic alpha(1)-adrenoceptors on vascular smooth muscle. This inhibits the vasoconstrictor effect of circulating and locally released catecholamines (epinephrine and norepinephrine), resulting in peripheral vasodilation.
Related Articles
AbsorptionWell-absorbed from gastrointestinal tract; bioavailability is variable (50 to 85%).
Volume of distributionNot Available
Protein binding97%
Metabolism

Primarily hepatic. Several metabolites have been identified in humans and animals (6- O -demethyl, 7- O -demethyl, 2-[1-piperazinyl]-4-amino-6, 7-dimethoxyquinazoline, 2,4-diamino-6,7-dimethoxyquinazoline).

SubstrateEnzymesProduct
Prazosin
Not Available
2,4-diamino-6,7-dimethoxyquinazolineDetails
Prazosin
Not Available
6-O-demethyl,7-O-demethyl,2-[1-piperazinyl]-4-amino-6,7-dimethoxyquinazolineDetails
Route of eliminationAnimal studies indicate that prazosin hydrochloride is extensively metabolized, primarily by demethylation and conjugation, and excreted mainly via bile and feces. Less extensive human studies suggest similar metabolism and excretion in man.
Half life2-3 hours
ClearanceNot Available
ToxicityNot Available
Affected organisms
  • Humans and other mammals
PathwaysNot Available
SNP Mediated EffectsNot Available
SNP Mediated Adverse Drug ReactionsNot Available
ADMET
Predicted ADMET features
PropertyValueProbability
Human Intestinal Absorption+1.0
Blood Brain Barrier+0.9479
Caco-2 permeable+0.8298
P-glycoprotein substrateSubstrate0.7193
P-glycoprotein inhibitor INon-inhibitor0.5747
P-glycoprotein inhibitor IINon-inhibitor0.8383
Renal organic cation transporterNon-inhibitor0.6405
CYP450 2C9 substrateNon-substrate0.8773
CYP450 2D6 substrateNon-substrate0.7641
CYP450 3A4 substrateSubstrate0.7577
CYP450 1A2 substrateNon-inhibitor0.8434
CYP450 2C9 inhibitorNon-inhibitor0.9278
CYP450 2D6 inhibitorNon-inhibitor0.9685
CYP450 2C19 inhibitorNon-inhibitor0.9169
CYP450 3A4 inhibitorNon-inhibitor0.7608
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.8049
Ames testNon AMES toxic0.5581
CarcinogenicityNon-carcinogens0.9199
BiodegradationNot ready biodegradable0.9818
Rat acute toxicity2.3304 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.8352
hERG inhibition (predictor II)Inhibitor0.8489
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397 )
Pharmacoeconomics
Manufacturers
  • Pfizer laboratories div pfizer inc
  • American therapeutics inc
  • Clonmel healthcare ltd
  • Ivax pharmaceuticals inc sub teva pharmaceuticals usa
  • Mylan pharmaceuticals inc
  • Purepac pharmaceutical co
  • Sandoz inc
  • Watson laboratories inc
  • Pfizer inc
Packagers
Dosage forms
FormRouteStrength
Tabletoral1 mg
Tabletoral2 mg
Tabletoral5 mg
Capsuleoral1 mg/1
Capsuleoral2 mg/1
Capsuleoral5 mg/1
Prices
Unit descriptionCostUnit
Minipress 5 mg capsule1.97USD capsule
Minipress 2 mg capsule1.14USD capsule
Prazosin HCl 5 mg capsule0.98USD capsule
Prazosin 5 mg capsule0.94USD capsule
Minipress 1 mg capsule0.83USD capsule
Prazosin HCl 2 mg capsule0.57USD capsule
Prazosin 2 mg capsule0.55USD capsule
Prazosin HCl 1 mg capsule0.41USD capsule
Prazosin 1 mg capsule0.4USD capsule
Apo-Prazo 5 mg Tablet0.4USD tablet
Novo-Prazin 5 mg Tablet0.4USD tablet
Nu-Prazo 5 mg Tablet0.4USD tablet
Vasoflex hd caplet0.38USD caplet
Vasoflex forte capsule0.29USD capsule
Apo-Prazo 2 mg Tablet0.29USD tablet
Novo-Prazin 2 mg Tablet0.29USD tablet
Nu-Prazo 2 mg Tablet0.29USD tablet
Apo-Prazo 1 mg Tablet0.22USD tablet
Novo-Prazin 1 mg Tablet0.22USD tablet
Nu-Prazo 1 mg Tablet0.22USD tablet
Vasoflex tablet0.15USD tablet
DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.
PatentsNot Available
Properties
StateSolid
Experimental Properties
PropertyValueSource
melting point279 °CPhysProp
water solubility0.5 mg/mL (HCl salt)Sigma Aldrich
logP1.3Not Available
Caco2 permeability-4.36ADME Research, USCD
Predicted Properties
PropertyValueSource
Water Solubility0.693 mg/mLALOGPS
logP1.93ALOGPS
logP1.65ChemAxon
logS-2.7ALOGPS
pKa (Strongest Basic)7.24ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count7ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area106.95 Å2ChemAxon
Rotatable Bond Count4ChemAxon
Refractivity104.5 m3·mol-1ChemAxon
Polarizability40.49 Å3ChemAxon
Number of Rings4ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Mass Spec (NIST)Not Available
Spectra
Spectrum TypeDescriptionSplash Key
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, NegativeNot Available
References
Synthesis Reference

Stig O. E. Lindholm, “A process for the preparation of anhydrous, stable, crystalline delta-form of prazosin hydrochloride.” U.S. Patent US4873330, issued 0000.

US4873330
General References
  1. Bawaskar HS, Bawaskar PH: Utility of scorpion antivenin vs prazosin in the management of severe Mesobuthus tamulus (Indian red scorpion) envenoming at rural setting. J Assoc Physicians India. 2007 Jan;55:14-21. [PubMed:17444339 ]
  2. Cushman WC, Ford CE, Cutler JA, Margolis KL, Davis BR, Grimm RH, Black HR, Hamilton BP, Holland J, Nwachuku C, Papademetriou V, Probstfield J, Wright JT Jr, Alderman MH, Weiss RJ, Piller L, Bettencourt J, Walsh SM: Success and predictors of blood pressure control in diverse North American settings: the antihypertensive and lipid-lowering treatment to prevent heart attack trial (ALLHAT). J Clin Hypertens (Greenwich). 2002 Nov-Dec;4(6):393-404. [PubMed:12461301 ]
  3. Hiraoka Y, Taniguchi T, Tanaka T, Okada K, Kanamaru H, Muramatsu I: Pharmacological characterization of unique prazosin-binding sites in human kidney. Naunyn Schmiedebergs Arch Pharmacol. 2003 Jul;368(1):49-56. Epub 2003 Jun 25. [PubMed:12827214 ]
  4. Link [Link]
External Links
ATC CodesC02LE01C02CA01
AHFS Codes
  • 24:20.00
PDB EntriesNot Available
FDA labelNot Available
MSDSDownload (57.2 KB)
Interactions
Drug Interactions
Drug
AcebutololAcebutolol may increase the orthostatic hypotensive activities of Prazosin.
AldesleukinThe risk or severity of adverse effects can be increased when Aldesleukin is combined with Prazosin.
AlfuzosinPrazosin may increase the antihypertensive activities of Alfuzosin.
AmifostinePrazosin may increase the hypotensive activities of Amifostine.
AmlodipinePrazosin may increase the hypotensive activities of Amlodipine.
AmrinonePrazosin may increase the hypotensive activities of Amrinone.
ArticainePrazosin may decrease the vasoconstricting activities of Articaine.
AtenololAtenolol may increase the orthostatic hypotensive activities of Prazosin.
AvanafilAvanafil may increase the hypotensive activities of Prazosin.
BendroflumethiazideBendroflumethiazide may increase the orthostatic hypotensive activities of Prazosin.
BepridilPrazosin may increase the hypotensive activities of Bepridil.
BetaxololBetaxolol may increase the orthostatic hypotensive activities of Prazosin.
BisoprololBisoprolol may increase the orthostatic hypotensive activities of Prazosin.
BrimonidineBrimonidine may increase the antihypertensive activities of Prazosin.
ButabarbitalButabarbital may increase the hypotensive activities of Prazosin.
ButethalButethal may increase the hypotensive activities of Prazosin.
CarteololCarteolol may increase the orthostatic hypotensive activities of Prazosin.
CarvedilolCarvedilol may increase the orthostatic hypotensive activities of Prazosin.
ClevidipinePrazosin may increase the hypotensive activities of Clevidipine.
DapoxetineDapoxetine may increase the orthostatic hypotensive activities of Prazosin.
DiazoxideDiazoxide may increase the hypotensive activities of Prazosin.
DiltiazemPrazosin may increase the hypotensive activities of Diltiazem.
DipivefrinPrazosin may decrease the vasoconstricting activities of Dipivefrin.
DopaminePrazosin may decrease the vasoconstricting activities of Dopamine.
DoxazosinPrazosin may increase the antihypertensive activities of Doxazosin.
DuloxetinePrazosin may increase the orthostatic hypotensive activities of Duloxetine.
EphedrinePrazosin may decrease the vasoconstricting activities of Ephedrine.
EpinephrinePrazosin may decrease the vasoconstricting activities of Epinephrine.
EsmololEsmolol may increase the orthostatic hypotensive activities of Prazosin.
FelodipinePrazosin may increase the hypotensive activities of Felodipine.
FlunarizinePrazosin may increase the hypotensive activities of Flunarizine.
GabapentinPrazosin may increase the hypotensive activities of Gabapentin.
HeptabarbitalHeptabarbital may increase the hypotensive activities of Prazosin.
HexobarbitalHexobarbital may increase the hypotensive activities of Prazosin.
IsradipinePrazosin may increase the hypotensive activities of Isradipine.
LabetalolLabetalol may increase the orthostatic hypotensive activities of Prazosin.
LamotriginePrazosin may increase the hypotensive activities of Lamotrigine.
LercanidipinePrazosin may increase the hypotensive activities of Lercanidipine.
LevodopaPrazosin may increase the orthostatic hypotensive activities of Levodopa.
LevonordefrinPrazosin may decrease the vasoconstricting activities of Levonordefrin.
Magnesium SulfatePrazosin may increase the hypotensive activities of Magnesium Sulfate.
MepivacainePrazosin may decrease the vasoconstricting activities of Mepivacaine.
MethohexitalMethohexital may increase the hypotensive activities of Prazosin.
MethylphenidateMethylphenidate may decrease the antihypertensive activities of Prazosin.
MetoprololMetoprolol may increase the orthostatic hypotensive activities of Prazosin.
MidodrinePrazosin may decrease the vasoconstricting activities of Midodrine.
MolsidomineMolsidomine may increase the hypotensive activities of Prazosin.
MoxonidineMoxonidine may increase the hypotensive activities of Prazosin.
NadololNadolol may increase the orthostatic hypotensive activities of Prazosin.
NaphazolinePrazosin may decrease the vasoconstricting activities of Naphazoline.
NebivololNebivolol may increase the orthostatic hypotensive activities of Prazosin.
NicardipinePrazosin may increase the hypotensive activities of Nicardipine.
NicorandilNicorandil may increase the hypotensive activities of Prazosin.
NifedipinePrazosin may increase the hypotensive activities of Nifedipine.
NimodipinePrazosin may increase the hypotensive activities of Nimodipine.
NisoldipinePrazosin may increase the hypotensive activities of Nisoldipine.
NitrendipinePrazosin may increase the hypotensive activities of Nitrendipine.
NorepinephrinePrazosin may decrease the vasoconstricting activities of Norepinephrine.
ObinutuzumabPrazosin may increase the hypotensive activities of Obinutuzumab.
OxymetazolinePrazosin may decrease the vasoconstricting activities of Oxymetazoline.
PenbutololPenbutolol may increase the orthostatic hypotensive activities of Prazosin.
PentobarbitalPentobarbital may increase the hypotensive activities of Prazosin.
PentoxifyllinePentoxifylline may increase the hypotensive activities of Prazosin.
PerhexilinePrazosin may increase the hypotensive activities of Perhexiline.
PhenelzinePhenelzine may increase the orthostatic hypotensive activities of Prazosin.
PheniraminePrazosin may decrease the vasoconstricting activities of Pheniramine.
PhenoxybenzaminePrazosin may increase the antihypertensive activities of Phenoxybenzamine.
PhentolaminePrazosin may increase the antihypertensive activities of Phentolamine.
PhenylephrinePrazosin may decrease the vasoconstricting activities of Phenylephrine.
PindololPindolol may increase the orthostatic hypotensive activities of Prazosin.
PrenylaminePrazosin may increase the hypotensive activities of Prenylamine.
PrimidonePrimidone may increase the hypotensive activities of Prazosin.
PropranololPropranolol may increase the orthostatic hypotensive activities of Prazosin.
PropylhexedrinePrazosin may decrease the vasoconstricting activities of Propylhexedrine.
PseudoephedrinePrazosin may decrease the vasoconstricting activities of Pseudoephedrine.
QuinineQuinine may increase the hypotensive activities of Prazosin.
RacepinephrinePrazosin may decrease the vasoconstricting activities of Racepinephrine.
RisedronatePrazosin may increase the hypotensive activities of Risedronate.
RisperidonePrazosin may increase the hypotensive activities of Risperidone.
RituximabPrazosin may increase the hypotensive activities of Rituximab.
SecobarbitalSecobarbital may increase the hypotensive activities of Prazosin.
SildenafilSildenafil may increase the hypotensive activities of Prazosin.
SilodosinPrazosin may increase the antihypertensive activities of Silodosin.
SotalolSotalol may increase the orthostatic hypotensive activities of Prazosin.
TadalafilTadalafil may increase the hypotensive activities of Prazosin.
TamsulosinPrazosin may increase the antihypertensive activities of Tamsulosin.
TerazosinPrazosin may increase the antihypertensive activities of Terazosin.
TimololTimolol may increase the orthostatic hypotensive activities of Prazosin.
TranylcypromineTranylcypromine may increase the orthostatic hypotensive activities of Prazosin.
TreprostinilTreprostinil may increase the hypotensive activities of Prazosin.
TriprolidinePrazosin may decrease the vasoconstricting activities of Triprolidine.
ValsartanThe risk or severity of adverse effects can be increased when Valsartan is combined with Prazosin.
VardenafilVardenafil may increase the hypotensive activities of Prazosin.
VerapamilPrazosin may increase the hypotensive activities of Verapamil.
YohimbineYohimbine may decrease the antihypertensive activities of Prazosin.
Food Interactions
  • Avoid alcohol.
  • Avoid natural licorice.
  • Take without regard to meals.

Targets

Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
antagonist
General Function:
Protein heterodimerization activity
Specific Function:
This alpha-adrenergic receptor mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. Its effect is mediated by G(q) and G(11) proteins. Nuclear ADRA1A-ADRA1B heterooligomers regulate phenylephrine(PE)-stimulated ERK signaling in cardiac myocytes.
Gene Name:
ADRA1A
Uniprot ID:
P35348
Molecular Weight:
51486.005 Da
References
  1. Chang HK, Hsu FL, Liu IM, Cheng JT: Stimulatory effect of cinnamic acid analogues on alpha1A-adrenoceptors in-vitro. J Pharm Pharmacol. 2003 Jun;55(6):833-7. [PubMed:12841945 ]
  2. Eltze M: In functional experiments, risperidone is selective, not for the B, but for the A subtype of alpha 1-adrenoceptors. Eur J Pharmacol. 1996 Jan 4;295(1):69-73. [PubMed:8925876 ]
  3. Morris DP, Price RR, Smith MP, Lei B, Schwinn DA: Cellular trafficking of human alpha1a-adrenergic receptors is continuous and primarily agonist-independent. Mol Pharmacol. 2004 Oct;66(4):843-54. Epub 2004 Jul 16. [PubMed:15258254 ]
  4. Sleight AJ, Koek W, Bigg DC: Binding of antipsychotic drugs at alpha 1A- and alpha 1B-adrenoceptors: risperidone is selective for the alpha 1B-adrenoceptors. Eur J Pharmacol. 1993 Jul 20;238(2-3):407-10. [PubMed:7691623 ]
  5. Suzuki Y, Kanada A, Okaya Y, Aisaka K: Effect of JTH-601, a novel alpha(1)-adrenoceptor antagonist, on prostate function in dogs. Eur J Pharmacol. 2000 Apr 7;394(1):123-30. [PubMed:10771044 ]
  6. Tomiyama Y, Kobayashi K, Tadachi M, Kobayashi S, Inada Y, Kobayashi M, Yamazaki Y: Expressions and mechanical functions of alpha1-adrenoceptor subtypes in hamster ureter. Eur J Pharmacol. 2007 Nov 14;573(1-3):201-5. Epub 2007 Jul 6. [PubMed:17658513 ]
  7. Zacharia J, Hillier C, MacDonald A: Alpha1-adrenoceptor subtypes involved in vasoconstrictor responses to exogenous and neurally released noradrenaline in rat femoral resistance arteries. Br J Pharmacol. 2004 Mar;141(6):915-24. Epub 2004 Feb 23. [PubMed:14980979 ]
  8. Cusack B, Nelson A, Richelson E: Binding of antidepressants to human brain receptors: focus on newer generation compounds. Psychopharmacology (Berl). 1994 May;114(4):559-65. [PubMed:7855217 ]
Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
antagonist
General Function:
Protein heterodimerization activity
Specific Function:
This alpha-adrenergic receptor mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. Its effect is mediated by G(q) and G(11) proteins. Nuclear ADRA1A-ADRA1B heterooligomers regulate phenylephrine (PE)-stimulated ERK signaling in cardiac myocytes.
Gene Name:
ADRA1B
Uniprot ID:
P35368
Molecular Weight:
56835.375 Da
References
  1. Al-Damluji S, Shen WB, White S, Barnard EA: alpha(1B) adrenergic receptors in gonadotrophin-releasing hormone neurones: relation to Transport-P. Br J Pharmacol. 2001 Jan;132(1):336-44. [PubMed:11156594 ]
  2. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. [PubMed:11752352 ]
  3. Eltze M: In functional experiments, risperidone is selective, not for the B, but for the A subtype of alpha 1-adrenoceptors. Eur J Pharmacol. 1996 Jan 4;295(1):69-73. [PubMed:8925876 ]
  4. Ishiguro M, Futabayashi Y, Ohnuki T, Ahmed M, Muramatsu I, Nagatomo T: Identification of binding sites of prazosin, tamsulosin and KMD-3213 with alpha(1)-adrenergic receptor subtypes by molecular modeling. Life Sci. 2002 Oct 11;71(21):2531-41. [PubMed:12270758 ]
  5. Sharpe IA, Thomas L, Loughnan M, Motin L, Palant E, Croker DE, Alewood D, Chen S, Graham RM, Alewood PF, Adams DJ, Lewis RJ: Allosteric alpha 1-adrenoreceptor antagonism by the conopeptide rho-TIA. J Biol Chem. 2003 Sep 5;278(36):34451-7. Epub 2003 Jun 24. [PubMed:12824165 ]
  6. Sleight AJ, Koek W, Bigg DC: Binding of antipsychotic drugs at alpha 1A- and alpha 1B-adrenoceptors: risperidone is selective for the alpha 1B-adrenoceptors. Eur J Pharmacol. 1993 Jul 20;238(2-3):407-10. [PubMed:7691623 ]
  7. Cusack B, Nelson A, Richelson E: Binding of antidepressants to human brain receptors: focus on newer generation compounds. Psychopharmacology (Berl). 1994 May;114(4):559-65. [PubMed:7855217 ]
Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
antagonist
General Function:
Alpha1-adrenergic receptor activity
Specific Function:
This alpha-adrenergic receptor mediates its effect through the influx of extracellular calcium.
Gene Name:
ADRA1D
Uniprot ID:
P25100
Molecular Weight:
60462.205 Da
References
  1. Nagaoka Y, Ahmed M, Hossain M, Bhuiyan MA, Ishiguro M, Nakamura T, Watanabe M, Nagatomo T: Amino acids of the human alpha1d-adrenergic receptor involved in antagonist binding. J Pharmacol Sci. 2008 Jan;106(1):114-20. Epub 2008 Jan 11. [PubMed:18187928 ]
  2. Yamamoto Y, Koike K: alpha(1)-Adrenoceptor subtypes in the mouse mesenteric artery and abdominal aorta. Br J Pharmacol. 2001 Nov;134(5):1045-54. [PubMed:11682453 ]
  3. Cusack B, Nelson A, Richelson E: Binding of antidepressants to human brain receptors: focus on newer generation compounds. Psychopharmacology (Berl). 1994 May;114(4):559-65. [PubMed:7855217 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
inhibitor
General Function:
Voltage-gated potassium channel activity involved in ventricular cardiac muscle cell action potential repolarization
Specific Function:
Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel. Channel properties are modulated by cAMP and subunit assembly. Mediates the rapidly activating component of the delayed rectifying potassium current in heart (IKr). Isoforms USO have no channel activity by themself, but modulates channel characteristics by forming heterotetramers with other isoforms which are r...
Gene Name:
KCNH2
Uniprot ID:
Q12809
Molecular Weight:
126653.52 Da
References
  1. Thomas D, Wimmer AB, Wu K, Hammerling BC, Ficker EK, Kuryshev YA, Kiehn J, Katus HA, Schoels W, Karle CA: Inhibition of human ether-a-go-go-related gene potassium channels by alpha 1-adrenoceptor antagonists prazosin, doxazosin, and terazosin. Naunyn Schmiedebergs Arch Pharmacol. 2004 May;369(5):462-72. Epub 2004 Apr 20. [PubMed:15098086 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
inhibitor
General Function:
Voltage-gated potassium channel activity
Specific Function:
Pore-forming (alpha) subunit of voltage-gated potassium channel. Elicits a slowly activating, rectifying current (By similarity). Channel properties may be modulated by cAMP and subunit assembly.
Gene Name:
KCNH6
Uniprot ID:
Q9H252
Molecular Weight:
109923.705 Da
References
  1. Thomas D, Wimmer AB, Wu K, Hammerling BC, Ficker EK, Kuryshev YA, Kiehn J, Katus HA, Schoels W, Karle CA: Inhibition of human ether-a-go-go-related gene potassium channels by alpha 1-adrenoceptor antagonists prazosin, doxazosin, and terazosin. Naunyn Schmiedebergs Arch Pharmacol. 2004 May;369(5):462-72. Epub 2004 Apr 20. [PubMed:15098086 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
inhibitor
General Function:
Voltage-gated potassium channel activity
Specific Function:
Pore-forming (alpha) subunit of voltage-gated potassium channel. Channel properties may be modulated by cAMP and subunit assembly.
Gene Name:
KCNH7
Uniprot ID:
Q9NS40
Molecular Weight:
134998.525 Da
References
  1. Thomas D, Wimmer AB, Wu K, Hammerling BC, Ficker EK, Kuryshev YA, Kiehn J, Katus HA, Schoels W, Karle CA: Inhibition of human ether-a-go-go-related gene potassium channels by alpha 1-adrenoceptor antagonists prazosin, doxazosin, and terazosin. Naunyn Schmiedebergs Arch Pharmacol. 2004 May;369(5):462-72. Epub 2004 Apr 20. [PubMed:15098086 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
binder
General Function:
Thioesterase binding
Specific Function:
Alpha-2 adrenergic receptors mediate the catecholamine-induced inhibition of adenylate cyclase through the action of G proteins. The rank order of potency for agonists of this receptor is oxymetazoline > clonidine > epinephrine > norepinephrine > phenylephrine > dopamine > p-synephrine > p-tyramine > serotonin = p-octopamine. For antagonists, the rank order is yohimbine > phentolamine = mianser...
Gene Name:
ADRA2A
Uniprot ID:
P08913
Molecular Weight:
48956.275 Da
References
  1. Uhlen S, Wikberg JE: Delineation of rat kidney alpha 2A- and alpha 2B-adrenoceptors with [3H]RX821002 radioligand binding: computer modelling reveals that guanfacine is an alpha 2A-selective compound. Eur J Pharmacol. 1991 Sep 17;202(2):235-43. [PubMed:1666366 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
binder
General Function:
Epinephrine binding
Specific Function:
Alpha-2 adrenergic receptors mediate the catecholamine-induced inhibition of adenylate cyclase through the action of G proteins. The rank order of potency for agonists of this receptor is clonidine > norepinephrine > epinephrine = oxymetazoline > dopamine > p-tyramine = phenylephrine > serotonin > p-synephrine / p-octopamine. For antagonists, the rank order is yohimbine > chlorpromazine > phent...
Gene Name:
ADRA2B
Uniprot ID:
P18089
Molecular Weight:
49565.8 Da
References
  1. Uhlen S, Wikberg JE: Delineation of rat kidney alpha 2A- and alpha 2B-adrenoceptors with [3H]RX821002 radioligand binding: computer modelling reveals that guanfacine is an alpha 2A-selective compound. Eur J Pharmacol. 1991 Sep 17;202(2):235-43. [PubMed:1666366 ]

Enzymes

Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
substrate
General Function:
Vitamin d 24-hydroxylase activity
Specific Function:
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics.
Gene Name:
CYP1A1
Uniprot ID:
P04798
Molecular Weight:
58164.815 Da
References
  1. Preissner S, Kroll K, Dunkel M, Senger C, Goldsobel G, Kuzman D, Guenther S, Winnenburg R, Schroeder M, Preissner R: SuperCYP: a comprehensive database on Cytochrome P450 enzymes including a tool for analysis of CYP-drug interactions. Nucleic Acids Res. 2010 Jan;38(Database issue):D237-43. doi: 10.1093/nar/gkp970. Epub 2009 Nov 24. [PubMed:19934256 ]

Carriers

Kind
Protein
Organism
Human
Pharmacological action
no
General Function:
Not Available
Specific Function:
Functions as transport protein in the blood stream. Binds various ligands in the interior of its beta-barrel domain. Also binds synthetic drugs and influences their distribution and availability in the body. Appears to function in modulating the activity of the immune system during the acute-phase reaction.
Gene Name:
ORM1
Uniprot ID:
P02763
Molecular Weight:
23511.38 Da
References
  1. Ferry DG, Caplan NB, Cubeddu LX: Interaction between antidepressants and alpha 1-adrenergic receptor antagonists on the binding to alpha 1-acid glycoprotein. J Pharm Sci. 1986 Feb;75(2):146-9. [PubMed:2870173 ]

Transporters

Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
substrateinhibitor
General Function:
Quaternary ammonium group transmembrane transporter activity
Specific Function:
Mediates tubular uptake of organic compounds from circulation. Mediates the influx of agmatine, dopamine, noradrenaline (norepinephrine), serotonin, choline, famotidine, ranitidine, histamin, creatinine, amantadine, memantine, acriflavine, 4-[4-(dimethylamino)-styryl]-N-methylpyridinium ASP, amiloride, metformin, N-1-methylnicotinamide (NMN), tetraethylammonium (TEA), 1-methyl-4-phenylpyridiniu...
Gene Name:
SLC22A2
Uniprot ID:
O15244
Molecular Weight:
62579.99 Da
References
  1. Hayer-Zillgen M, Bruss M, Bonisch H: Expression and pharmacological profile of the human organic cation transporters hOCT1, hOCT2 and hOCT3. Br J Pharmacol. 2002 Jul;136(6):829-36. [PubMed:12110607 ]
  2. Pan G, Winter TN, Roberts JC, Fairbanks CA, Elmquist WF: Organic cation uptake is enhanced in bcrp1-transfected MDCKII cells. Mol Pharm. 2010 Feb 1;7(1):138-45. doi: 10.1021/mp900177r. [PubMed:19886673 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
inhibitor
General Function:
Secondary active organic cation transmembrane transporter activity
Specific Function:
Translocates a broad array of organic cations with various structures and molecular weights including the model compounds 1-methyl-4-phenylpyridinium (MPP), tetraethylammonium (TEA), N-1-methylnicotinamide (NMN), 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP), the endogenous compounds choline, guanidine, histamine, epinephrine, adrenaline, noradrenaline and dopamine, and the drugs quinine...
Gene Name:
SLC22A1
Uniprot ID:
O15245
Molecular Weight:
61153.345 Da
References
  1. Hayer-Zillgen M, Bruss M, Bonisch H: Expression and pharmacological profile of the human organic cation transporters hOCT1, hOCT2 and hOCT3. Br J Pharmacol. 2002 Jul;136(6):829-36. [PubMed:12110607 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
inhibitor
General Function:
Toxin transporter activity
Specific Function:
Mediates potential-dependent transport of a variety of organic cations. May play a significant role in the disposition of cationic neurotoxins and neurotransmitters in the brain.
Gene Name:
SLC22A3
Uniprot ID:
O75751
Molecular Weight:
61279.485 Da
References
  1. Hayer-Zillgen M, Bruss M, Bonisch H: Expression and pharmacological profile of the human organic cation transporters hOCT1, hOCT2 and hOCT3. Br J Pharmacol. 2002 Jul;136(6):829-36. [PubMed:12110607 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
substrateinhibitor
General Function:
Xenobiotic-transporting atpase activity
Specific Function:
Energy-dependent efflux pump responsible for decreased drug accumulation in multidrug-resistant cells.
Gene Name:
ABCB1
Uniprot ID:
P08183
Molecular Weight:
141477.255 Da
References
  1. Polli JW, Wring SA, Humphreys JE, Huang L, Morgan JB, Webster LO, Serabjit-Singh CS: Rational use of in vitro P-glycoprotein assays in drug discovery. J Pharmacol Exp Ther. 2001 Nov;299(2):620-8. [PubMed:11602674 ]
  2. Nagy H, Goda K, Fenyvesi F, Bacso Z, Szilasi M, Kappelmayer J, Lustyik G, Cianfriglia M, Szabo G Jr: Distinct groups of multidrug resistance modulating agents are distinguished by competition of P-glycoprotein-specific antibodies. Biochem Biophys Res Commun. 2004 Mar 19;315(4):942-9. [PubMed:14985103 ]
  3. Takara K, Sakaeda T, Kakumoto M, Tanigawara Y, Kobayashi H, Okumura K, Ohnishi N, Yokoyama T: Effects of alpha-adrenoceptor antagonist doxazosin on MDR1-mediated multidrug resistance and transcellular transport. Oncol Res. 2009;17(11-12):527-33. [PubMed:19806783 ]
  4. Dohse M, Scharenberg C, Shukla S, Robey RW, Volkmann T, Deeken JF, Brendel C, Ambudkar SV, Neubauer A, Bates SE: Comparison of ATP-binding cassette transporter interactions with the tyrosine kinase inhibitors imatinib, nilotinib, and dasatinib. Drug Metab Dispos. 2010 Aug;38(8):1371-80. doi: 10.1124/dmd.109.031302. Epub 2010 Apr 27. [PubMed:20423956 ]
  5. Dey S, Ramachandra M, Pastan I, Gottesman MM, Ambudkar SV: Evidence for two nonidentical drug-interaction sites in the human P-glycoprotein. Proc Natl Acad Sci U S A. 1997 Sep 30;94(20):10594-9. [PubMed:9380680 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
substrateinhibitor
General Function:
Xenobiotic-transporting atpase activity
Specific Function:
High-capacity urate exporter functioning in both renal and extrarenal urate excretion. Plays a role in porphyrin homeostasis as it is able to mediates the export of protoporhyrin IX (PPIX) both from mitochondria to cytosol and from cytosol to extracellular space, and cellular export of hemin, and heme. Xenobiotic transporter that may play an important role in the exclusion of xenobiotics from t...
Gene Name:
ABCG2
Uniprot ID:
Q9UNQ0
Molecular Weight:
72313.47 Da
References
  1. Dohse M, Scharenberg C, Shukla S, Robey RW, Volkmann T, Deeken JF, Brendel C, Ambudkar SV, Neubauer A, Bates SE: Comparison of ATP-binding cassette transporter interactions with the tyrosine kinase inhibitors imatinib, nilotinib, and dasatinib. Drug Metab Dispos. 2010 Aug;38(8):1371-80. doi: 10.1124/dmd.109.031302. Epub 2010 Apr 27. [PubMed:20423956 ]
  2. Ozvegy C, Litman T, Szakacs G, Nagy Z, Bates S, Varadi A, Sarkadi B: Functional characterization of the human multidrug transporter, ABCG2, expressed in insect cells. Biochem Biophys Res Commun. 2001 Jul 6;285(1):111-7. [PubMed:11437380 ]
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Drug created on June 13, 2005 07:24 / Updated on August 17, 2016 12:23