L17 Adrenoceptor antagonist - alpha blockers Flashcards
Phenoxybenzamine is which alpha receptors blocker?
- a1 & a2
Effects of phenoxybenzamine on alpha receptors
- a1: orthostatic hypotension
- a2: tarcycardia
Therapeutic uses of phenoxybenzamine
- Pheochromocytoma
Side effects of phenoxybenzamine
nasal stuffiness
orthostatic hypotension
tarchycardia
inhibition of ejaculation
fatigue
nausea
Phentolamine is which alpha receptors blocker?
a1 , a2
Therapeutic use of phentolamine
Pheochromocytoma
Side effects of phentolamine
Orthostatic hypotension
Tachycardia
Arrhythmias
Myocardial ischemia
Prazosin is which alpha antagonist
a1
Therapeutic use of prazosin
Antihypertensive
treat BPH (urinary retention)
Side effect of prazosin
1st dose phenomenon - sudden and severe drop in BP when change from lying to standing position
- Hypotension
- Nasal congestion
- Headache
- Drowsiness
- Tiredness
- Palpitation
Yohimbine is which alpha antagonist
- a2
Uses of yohimbine (4)
- treat orthostatic hypotension
- increase BP
- veterinary medicine to reverse anaesthesia produce by xylazine
- treat erectile dysfunction
Which alpha antagonists cause pheochromocytoma
- Phenoxybenzamine
- Phentolamine
Treat hypertensive emergencies
- labetalol (a1 antagonist) is useful in high BP due to excess circulating conc. of alpha agonists
Chronic hypertension
- prazosin