Alpha Blockers

Question 1

What are the drugs under the alpha blocker class and what is their MOA?

Answer 1

Prazosin, Doxazosin, Terazosin
(Zosins)

Alpha blockers work by blocking alpha 1 receptors in the smooth muscles of arteries and veins. Normally, stimulation of alpha 1 receptors by norepinephrine leads to vasoconstriction and high BP but by blocking these receptors, it causes vasodilation and relaxation of smooth muscle.

Question 2

What are conditions that alpha blockers would be prescribed for?

Answer 2

HTN (add-on therapy due to potential side effects)

BPH (relaxes smooth muscle in the bladder, neck, and prostate which relieves urinary symptoms.

Question 3

What are contraindications for taking alpha blockers?

Answer 3

Hypotension
History of Orthostatic hypotension

Question 4

What are drug-drug interactions to watch for with alpha blockers?

Answer 4

PDE-5 Inhibitors (sildenafil)
Antihypertensive drugs

Question 5

How should dosage be adjusted when a patient is prescribed alpha blockers?

Answer 5

they require slow titration because of the risk of first dose hypotension, a marked drop in BP that occurs after the first especially when standing up. It is usually recommended to start with a low dose taken at bedtime.

Question 6

What are side effects of alpha blockers?

Answer 6

Orthostatic hypotension
Reflex tachycardia