Which of the following alpha-blocker drug is used in the treatment of benign hypertrophy of prostate without producing significant hypotension?

Ans. d (Tamsulosin). (Ref. KD Tripathi 6th/pg. 135)DRUG USED FOR BHP# Alpha-adrenergic blockers:- Terazosin,- Tamsulosin,- Doxazosin:# A 5-a reductase inhibitor - finasteride- Finasteride prevents conversion of testosterone to dihydrotestosterone.# Cyproterone acetate (Anti-androgenic drug) is used for medical castration.Terazosin# It is reversible al-selective antagonist that is effective in hypertension;# It has also been approved for use in men with urinary symptoms due to BPH.# Terazosin has high bioavailability# But is extensively metabolized in liver (only a small unchanged fraction excreted in urine)# The half-life of terazosin is 9-12 hours.Doxazosin# Is efficacious in the treatment of hypertension and BPH.# It differs from prazosin and terazosin in having a longer half-life of about 22 hours.# It has moderate bioavailability and is extensively metabolized, with very little parent drug excreted in urine or feces.# Doxazosin has active metabolites, although contribution to the drug's effects is probably small.Tamsulosin# It is an uroselective a1A/1D antagonist with a structure quite different from that of most other al-receptor blockers.Q# It has high bioavailability and a long half-life of 9-15 hours.# It is metabolized extensively in the liver.# Tamsulosin has higher affinity for alA and alD receptors than for the alB subtype.# The drug's efficacy in BPH suggests that the alA subtype may be the most important subtype mediating prostate smooth muscle contraction.# Furthermore, compared with other antagonists, tamsulosin has less effect on standing blood pressure in patients (causes minimal vascular side effects).# Dizziness and retrograde ejaculation are the only vital side-effects.Alfuzosin# is an al-selective quinazoline derivative that has also been shown to be efficacious in BPH. It has bioavailability of 60%, is extensively metabolized, and has elimination halflife of about 5 hours.Indoramin# It is another al-selective antagonist that also has efficacy as an antihypertensive.Urapidil# It is an al antagonist (its primary effect) that also has weak 2-agonist and 5-HTlA-agonist actions and weak antagonist action at al receptors.# It is used in Europe as an antihypertensive agent and for benign prostatic hyperplasia.