alpha blockers

Question 1

name some alpha blockers

Answer 1

doxazosin, tamsulosin, alfuzosin, prazosin

Question 2

Indications for alpha blockers

Answer 2

HTN (later line)
BPH
hyperhidrosis
raynauds

Question 3

how do alpha blockers work?

Answer 3

block alpha-1-adrenoceptors found on smooth muscle - including in blood vessels and urinary tract. Blockade induces relaxation. → vascular smooth muscle relaxation and reduction in arterial BP

Question 4

why do alpha blockers help BPH?

Answer 4

sympathetic nervous system (alpha adrenergic receptors) is involved with urinary retention (detrusor relaxation and sphincter constriction) by blocking this alpha blockers have a “parasympathetic effect” whereby it relaxes the urinary sphincter leading to better urianry flow and improvement of LUTS

Question 5

in what circumstances are alpha blockers contraindicated?

Answer 5

people with micturition syncope,
severe hepatic impairment,
postural hypotension,
post-cataract,

Question 6

adverse effects alpha blockers

Answer 6

postural hypotension, dizziness, syncope

Question 7

when should you take alpha blovkers

Answer 7

take at bedtime due to blood pressure lowering effect

Question 8

dose tamsulosin bph

Answer 8

400mcg od

Question 9

dose doxazosin HTN and BPH

Answer 9

initially 1mg od for 1-2 weeks then increased by doubling - up to max 16mg for HTN and up to 8mg for BPH.

if modified release start 4mg, can be increased to 8mg for both HTN and BPH

Question 10

what alpha blocker would you use in HTN if neccessary

Answer 10

doxazosin