E2: α antagonists

Question 1

Reserpine is a ______ agent

Answer 1

sympatholytic

Question 2

What natural product is mentioned with regard to Reserpine

Answer 2

Rauwolfia serpentina

Question 3

Reserpine MOA

Answer 3

Irreversibly blocks uptake of catecholamine (NE, dopamine) and biogenic amines (serotonin) into storage vesicles
Blocks vesicular membrane associated transporter (VMAT)
Causes depletion of EPI, NE, dopamine in peripheral sympathetic nerve fibers
Gradual loss of neurotransmitters from vesicles

Question 4

α1 selective adrenergic antagonists for CVD (3)

Answer 4

doxazosin-Cardura
prazosin-Minipress
terazocin-Hytrin

Question 5

Non-selective α1α2 adrenergic antagonist reversible (1)

Answer 5

phentolamine-Regitine

Question 6

Non-selective α1α2 adrenergic antagonist (1)Irreversible

Answer 6

phenoxybenzamine-Dibenyzline

Question 7

alpha1 adrenergic antagonists for urinary disease (BPH) (3)

Answer 7

Alfuzosin-UroXatral
Silodosin-Rapaflo
Tamsulosin-Flomax

Question 8

Indication of alpha-1 selective adrenergic antagonists (4)

Answer 8

HTN (systemic antagonists)
* Tolerance to blood pressure lowering effect occurs with time
Benign prostatic hyperplasia (BPH)
Pass kidney stones
Post traumatic stress disorder (PTSD)

Question 9

Which alpha1 selective adrenergic agonists require first dose 1mg PO HS then ↑ to 5-10mg

Answer 9

terazosin, doxazosin, prazosin

Question 10

Which alpha1 selective adrenergic agonists do not require titrated doses

Answer 10

alfuzosin, silodosin, tamsulosin

Question 11

which drug(s) effect on urinary disease peak within days

Answer 11

tamsulosin

Question 12

which drug has some improvement in urinary flow w/in days but the full effect takes 2-3 weeks

Answer 12

terazosin

Question 13

Which agent specifically can be used in PTSD patho and why
How is it dosed

Answer 13

Prazosin
-lipid soluble, crosses BBB and dampens NE effects
-therapeutic dose is unpredictable, dose to effect

Question 14

What is the general MOA and pharmacologic effects of α1 adrenergic antagonists

Answer 14

competitive antagonist of NE, EPI at α1 receptors

1. vasodilation of blood vessels which blocks NE at alpha1 receptor (↓TPR.. ↓BP)
2. non-uroselectives improves plasma lipid profile (↓TC, ↓LDL, ↓HDL)
3. uroselective agents: α1A receptor antagonism causes relaxation of smooth muscle in trigone, urethra, and prostate

Question 15

ADR and DI of α1-selective adrenergic antagonist

Answer 15

1. first dose syncope in systemic antagonists (-azosin), give HS at lower doses
2. abnormal ejaculation
3. reflex tachycardia, palpitations w/non-selectives

DI: PDE 5 inhibitors (sildenafil, vardenafil, tadalafil) have potential for hypotension w/new Rx or ↑dose

Question 16

alpha 1 receptor antagonists structural features and their effect

Answer 16

quinazolines and acyl moiety (↑ a1 receptor affinity, ↓metabolism, ↑DOA)

Question 17

What agent has the specific ADR of intraoperative floppy iris syndrome (IFIS) during cataract surgery

Answer 17

Tamsulosin-Flomax

Question 18

What is the warning for Tamsulosin due to it’s chemical structure

Answer 18

avoid w/severe sulfa allergies due to presence of aryl sulfonamide

Question 19

What agent has a indole carboxamide SAR and what class is it

Answer 19

silodosin-Rapaflo, alpha1A selective antagonist

Question 20

What type of kinetics (metabolism) does sildosin-Rapaflo have

Answer 20

CYP3A4 substrate

Question 21

Indication and MOA of phentolamine-Regitine

Answer 21

Indication:
Hypertensive episodes in patients w/pheochromocytoma (tumor of adrenal medulla)
Hypertensive urgency/emergency in associate w/excess catecholamine release due to illicit drugs

MOA: REVERSIBLE blockade of α1α2 receptors in various organs

Question 22

Indication, MOA, Warning of phenoxybenzamine

Answer 22

Indication: sweating/HTN associated w/phenochromocytoma
MOA: irreversible blockade (covalent binding) of α1α2 receptors in various organs
Warnings/precautions: not intended for long-term use