III. Mechanism: Benign Prostatic Hypertrophy

  1. Background
    1. Non-Selective Postsynaptic Alpha Adrenergic Antagonist (Terazosin, Doxazosin, Prazosin)
      1. Relatively weak antihypertensives, were often used for BPH
    2. Selective Alpha-1a Antagonist
      1. Developed for specific Alpha-1a activity with minimal antihypertensive effects
  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: Selective Alpha-1a Antagonists (Prostate specific agents)

  1. Precautions
    1. Still cause Orthostatic Hypotension, fall risk, Head Trauma and Fractures, despite selective nature
    2. Number needed to harm (NNH): 600 for fall-related hospitalizations, and 1600 for fall-related Fractures
    3. Welk (2015) BMJ 351:h5398 +PMID:26502947 [PubMed]
  2. Alfuzosin (Uroxatral, generic)
    1. Dose: 10 mg once daily
    2. Contraindicated in moderate to severe liver disease (and Exercise caution in renal disease)
  3. Silodosin (Rapaflo)
    1. Dose: 8 mg daily with food (4 mg daily if GFR 30-50 ml/min)
    2. Contraindicated when GFR <30 ml/min or severe liver disease (Child-Pugh Score 10 or more)
  4. Tamsulosin (Flomax, generic)
    1. Dose 0.4 mg orally daily (maximum 0.8 mg/day)

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Related Studies

Cost: Medications

tamsulosin (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
TAMSULOSIN HCL 0.4 MG CAPSULE Generic $0.14 each
flomax (on 1/4/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
FLOMAX 0.4 MG CAPSULE Generic $0.14 each
alfuzosin (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
ALFUZOSIN HCL ER 10 MG TABLET Generic $0.17 each
uroxatral (on 5/18/2016 at Medicaid.Gov Survey of pharmacy drug pricing)
UROXATRAL 10 MG TABLET Generic $0.17 each
rapaflo (on 2/22/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
RAPAFLO 4 MG CAPSULE $7.30 each
RAPAFLO 8 MG CAPSULE $7.29 each

Ontology: tamsulosin (C0257343)

Definition (NCI_NCI-GLOSS) 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 Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH C088482
SnomedCT 108559004, 372509005
LNC LP171642-4
English 5-(2-((2-(2-ethoxyphenoxy)ethyl)amino)propyl)-2-methoxybenzenesulfonamide, tamsulosin, 5-((2R)-2-(2-(2-ethoxyphenoxy)ethylamino)propyl)-2-methoxy-benzenesulfonamide, tamsulosin [Chemical/Ingredient], TAMSULOSIN, Tamsulosin, Tamsulosin (product), Tamsulosin (substance)
Spanish tamsulosina (producto), tamsulosina (sustancia), tamsulosina

Ontology: Flomax (C0662903)

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