I. Indications

II. Mechanism: General

  1. See Alpha Adrenergic Receptor (Alpha-1 antagonist)

III. Mechanism: Benign Prostatic Hypertrophy

  1. Preparations used in Benign Prostatic Hypertrophy
    1. Terazosin (Hytrin)
    2. Doxazosin (Cardura)
    3. Tamsulosin (Flomax)
    4. Prazosin (Minipress)
  2. Rapid relaxation of smooth muscle tone
    1. Bladder neck
    2. Prostate Capsule
    3. Prostatic Urethra
  3. Relieves symptoms of urinary obstruction
    1. May see full effect within 2 weeks
  4. Does not effect size of Prostate (unlike Proscar)

IV. Preparations

  1. Prazosin (Minipress)
    1. Dose: 1 mg PO bid-tid (Maximum 40 mg/day)
    2. Less expensive but not available for once daily dose
  2. Terazosin (Hytrin)
    1. Dose: 1 mg PO qhs (Maximum 20 mg/day)
  3. Doxazosin (Cardura)
    1. Dose: 1 mg PO qd (Maximum 16 mg/day)
  4. Phenoxybenzamine (Dibenzyline)
    1. Dose: 10 mg PO bid (Maximum 120 mg/day)
  5. Tamsulosin (Flomax)
    1. More expensive than other agents
    2. Dose 0.4 mg PO qd (maximum 0.8 mg/day)
    3. Highly selective alpha-1a blocker
      1. Does not effect Blood Pressure
      2. May be more effective in BPH than other agents

V. Combination Alpha-Beta Antagonist (Labetalol or Trandate)

  1. Oral: 100 mg PO bid (Maximum: 2400 mg/day)
  2. Intravenous: 20 mg IV q10 minutes (Maximum: 200 mg)

VI. Adverse effects (Incidence: 7 to 9%)

  1. Dose at bed and slowly titrate to reduce side effects
  2. Cardiovascular adverse effects (not Tamsulosin)
    1. Dizziness
    2. Postural Hypotension
  3. Other adverse effects
    1. Fatigue
    2. Asthenia

VII. Precautions

  1. Avoid using as monotherapy for Hypertension
    1. Higher risk of CVA and CHF compared with other agents
    2. (2000) JAMA 283:1967-75 [PubMed] (or open in [QxMD Read])

Images: Related links to external sites (from Google)

Cost: Medications

PRAZOSIN HCL (on 2/10/2012 at Target.com)
PRAZOSIN HCL 1 MG Capsule #30 for $4.00 ($0.13/unit)
PRAZOSIN HCL 2 MG* Capsule #30 for $4.00 ($0.13/unit)
PRAZOSIN HCL 5 MG* Capsule #30 for $4.00 ($0.13/unit)
TERAZOSIN (on 2/10/2012 at Target.com)
TERAZOSIN 1 MG Capsule #30 for $4.00 ($0.13/unit)
TERAZOSIN 2 MG Capsule #30 for $4.00 ($0.13/unit)
TERAZOSIN 5 MG Capsule #30 for $4.00 ($0.13/unit)
TERAZOSIN 10 MG Capsule #30 for $4.00 ($0.13/unit)
DOXAZOSIN (on 2/10/2012 at Target.com)
DOXAZOSIN 1 MG Tablet #30 for $4.00 ($0.13/unit)
DOXAZOSIN 2 MG Tablet #30 for $4.00 ($0.13/unit)
DOXAZOSIN 4 MG Tablet #30 for $4.00 ($0.13/unit)
DOXAZOSIN 8 MG Tablet #30 for $4.00 ($0.13/unit)
Prazosin HCl (on 2/9/2012 at DrugStore.com)
Prazosin HCl 1mg Capsules #60 for $17.99 ($0.30/unit)
Prazosin HCl 2mg Capsules #60 for $24.99 ($0.42/unit)
Prazosin HCl 5mg Capsules #60 for $37.99 ($0.63/unit)
Minipress (on 2/9/2012 at DrugStore.com)
Minipress 1mg Capsules #60 for $55.89 ($0.93/unit)
Minipress 2mg Capsules #60 for $75.24 ($1.25/unit)
Minipress 5mg Capsules #60 for $133.29 ($2.22/unit)
Terazosin HCl (on 2/9/2012 at DrugStore.com)
Terazosin HCl 1mg Capsules #30 for $15.99 ($0.53/unit)
Terazosin HCl 2mg Capsules #30 for $13.99 ($0.47/unit)
Terazosin HCl 5mg Capsules #30 for $13.99 ($0.47/unit)
Terazosin HCl 10mg Capsules #30 for $13.99 ($0.47/unit)
Doxazosin Mesylate (on 2/9/2012 at DrugStore.com)
Doxazosin Mesylate 1mg Tablets #30 for $17.99 ($0.60/unit)
Doxazosin Mesylate 2mg Tablets #30 for $20.99 ($0.70/unit)
Doxazosin Mesylate 4mg Tablets #30 for $21.99 ($0.73/unit)
Doxazosin Mesylate 8mg Tablets #30 for $23.99 ($0.80/unit)
Cardura XL (on 2/9/2012 at DrugStore.com)
Cardura XL 4mg 24 Hour Tablets #30 for $64.04 ($2.13/unit)
Cardura XL 8mg 24 Hour Tablets #30 for $67.20 ($2.24/unit)
Cardura (on 2/9/2012 at DrugStore.com)
Cardura 1mg Tablets #30 for $55.63 ($1.85/unit)
Cardura 2mg Tablets #30 for $55.99 ($1.87/unit)
Cardura 4mg Tablets #30 for $66.49 ($2.22/unit)
Cardura 8mg Tablets #30 for $66.49 ($2.22/unit)
Tamsulosin HCl (on 2/9/2012 at DrugStore.com)
Tamsulosin HCl 0.4mg Capsules #30 for $122.99 ($4.10/unit)
Flomax (on 2/9/2012 at DrugStore.com)
Flomax 0.4mg Capsules #30 for $153.99 ($5.13/unit)

Ontology: Prazosin (C0032912)

Definition (NCI) A synthetic piperazine derivative and an alpha-1 adrenergic receptor inhibitor used primarily as an anti-hypertensive. Prazosin's effects are most pronounced in the large resistance vessels (i.e. arterioles) and result in a decrease in total systemic vascular resistance (SVR) without a rebound or reflex tachycardia. To a lesser extent, this agent also decreases the tone of the bladder sphincter, thereby allowing the opening of the bladder into the urethra and thus relieving the urinary conditions associated with benign prostatic hypertrophy.
Definition (MSH) A selective adrenergic alpha-1 antagonist used in the treatment of HEART FAILURE; HYPERTENSION; PHEOCHROMOCYTOMA; RAYNAUD DISEASE; PROSTATIC HYPERTROPHY; and URINARY RETENTION.
Definition (CSP) 1-(4-amino-6,7-dimethoxy- 2-quinazolinyl) -4-(2-furoyl) piperazine.
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D011224
SnomedCT 387283005, 387433003, 76058001, 51505001, 367555002
English Furazosin, Prazosin, prazosin, Piperazine, 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)-, 2-[4-(2-furoyl)piperazin-1-yl]-4-amino-6,7-dimethoxyquinazoline, 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)piperazine, Prazosin [Chemical/Ingredient], Prazosin (product), Prazosin (substance), Furazosin (substance), Furazosin (product), PRAZOSIN
Swedish Prazosin
Spanish furazosín, furazosina, furazosín (producto), prazosina (producto), prazosín (producto), furazosina (sustancia), prazosina (sustancia), prazosina, prazosín, Furazosina, Prazosina
Czech prazosin
Finnish Pratsosiini
Japanese プラゾシン, 塩酸プラゾシン, フラゾシン
Italian Furazosina, Prazosina
Polish Prazosyna
French Prazosine
German Furazosin, Prazosin
Portuguese Furazosin, Prazosina

Ontology: Terazosin (C0076107)

Definition (NCI) A drug used to treat urinary problems caused by an enlarged prostate. It is also used to treat high blood pressure and is being studied in the treatment of other conditions. Terazosin relaxes muscle tissue in blood vessels and in the prostate. It is a type of alpha blocker.
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH C041226
SnomedCT 349914007, 129484001, 387068008
English terazosin, Terazosin, Terazosin [Chemical/Ingredient], terazosine, Terazosin (product), Terazosin (substance), TERAZOSIN
Spanish Terazosin, terazosina (producto), terazosina (sustancia), terazosina

Ontology: Doxazosin (C0114873)

Definition (MSH) A prazosin-related compound that is a selective alpha-1-adrenergic blocker.
Definition (NCI) A drug used to treat high blood pressure and urinary problems caused by an enlarged prostate. It relaxes muscle tissue in blood vessels and in the prostate. Cardura is a type of alpha blocker.
Definition (NCI) A quinazoline with antihypertensive and antineoplastic properties. Doxazosin is an alpha-adrenergic antagonist that selectively inhibits alpha-1 adrenergic receptors. Blockages of the alpha-1 adrenergic action on the vascular smooth muscles lead to a decrease in vascular resistance and antihypertensive activity. This agent also shows high affinity to alpha-1c adrenoceptor, the predominant functional type in the prostate, which may partially attribute to its effect in treatment of benign prostatic hyperplasia. Furthermore, doxazosin induces apoptosis in prostate cancer cells mediated through inhibition of protein kinase B (PKB)/Akt-signaling death receptor regulatory pathway.
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D017292
SnomedCT 108556006, 372508002
English Doxazosin, Piperazine, 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-((2,3-dihydro-1,4-benzodioxin-2-yl)carbonyl)-, doxazosin, Doxazosin [Chemical/Ingredient], Doxazosin (product), Doxazosin (substance), DOXAZOSIN
Swedish Doxazosin
Czech doxazosin
Finnish Doksatsosiini
Japanese ドキサゾシン, ドキサゾシンメシレート, メシル酸ドキサゾシン
Spanish Doxazosin, Doxazosina, doxazosina (producto), doxazosina (sustancia), doxazosina
Portuguese Doxazosina, Doxazossina, Doxazosin
Polish Doksazosyna, Metylosulfonian doksazosyny
French Doxazosine
German Doxazosin
Italian Dossazosina

Ontology: Minipress (C0242447)

Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D011224
English Pfizer Brand of Prazosin Hydrochloride, minipress, Minipress

Ontology: tamsulosin (C0257343)

Definition (NCI) A drug used to treat urinary problems caused by an enlarged prostate. Tamsulosin relaxes the muscles of the prostate and bladder, which helps the flow of urine. It is a type of alpha blocker.
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH C088482
SnomedCT 108559004, 372509005
English 5-(2-((2-(2-ethoxyphenoxy)ethyl)amino)propyl)-2-methoxybenzenesulfonamide, tamsulosin, 5-((2R)-2-(2-(2-ethoxyphenoxy)ethylamino)propyl)-2-methoxy-benzenesulfonamide, TAMSULOSIN, tamsulosin [Chemical/Ingredient], Tamsulosin, Tamsulosin (product), Tamsulosin (substance)
Spanish tamsulosina (producto), tamsulosina (sustancia), tamsulosina

Ontology: Hytrin (C0591628)

Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH C041226
English Hytrin BPH, Abbott Brand of Terazosin Hydrochloride, hytrin, hytrin bph, Hytrin, Deflox, Flotrin, Heitrin, Hytrine

Ontology: Flomax (C0662903)

Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH C088482
English Flomax, Abbott laboratories brand of tamsulosin hydrochloride, flomax

Ontology: Cardura (C0678136)

Definition (MSH) Trade name in United States.
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D017292
English Carduran, cardura, carduran, Cardura, Cardular, Pfizer Brand of Doxazosin Mesylate, Zoxan