B.7- 𝝰 receptor antagonists

Question 1

classify the direct-acting sympatholytics (𝝰 adrenoreceptor antagonists)

Answer 1

non-selective and selective 𝝰 receptor antagonists

Question 2

what are the non-selective 𝝰 receptor antagonists?

Answer 2

phentolamine

Phenoxybenzamine

Question 3

what are the 2 differences between phentolamine and phenoxybenzamine?

Answer 3

1. phentolamine reversible inhibition, phenoxy irreversible (covalent binding)
2. phenoxybenzamine longer duration of action, up to 48 h, and phentolamine only 2-4 hours.

Question 4

indications for phentolamine and phenoxybenzamine

Answer 4

1. preoperative management of pheochromocytoma

2. antidote in case of acute hypertension due to 𝝰-agonist overdose (cocaine, amphetamine, tyramine)

Question 5

what is the SE of phentolamine and phenoxybenzamine?

Answer 5

orthostatic hypotension with reflex tachycardia

*give B blocker with phentolamine in pheochromocytoma attack

Question 6

name the selective 𝝰-receptor antagonists

Answer 6

prazosin
doxazosin
tamsulosin

urapidil

mirtazapine

Question 7

what are the targets of Urapidil?

Answer 7

𝝰1 antagonist
𝝰2 week agonist
5-HT weak agonist
β- antagonist

Question 8

how are the selective 𝝰 receptor antagonists given?

Answer 8

oral

Question 9

what is the target receptor of prazosin?

Answer 9

𝝰1 selective

Question 10

what is the target receptor of mirtazapine?

Answer 10

𝝰2 selective

Question 11

indications for prazosin, doxazosin and tamsulosin ?

Answer 11

hypertension (vasodilation)
BPH–> relaxes the muscles of the prostate and bladder neck which allows urine to flow more easily
PTSD-Prazosin

Question 12

SE of prazosin?

Answer 12

orthostatic hypotension
↑ HDL
inhibit ejaculation

Question 13

indications of Urapidil

Answer 13

BPH
hypertension
hypertensive crisis

Question 14

indication of mirtazapine

Answer 14

antidepressant