ANS Sympatholytics

Question 1

α-methyltyrosine (metyrosine)

Answer 1

inhibitor of tyrosine hydroxylase (rate limiting catecholamine step), treatment of inoperable pheochromocytoma

Question 2

Carbidopa

Answer 2

inhibitor of aromatic L-amino acid decarboxylase, inhibits metabolism of levodopa to DA in periphery but not in CNS. combine with levodopa to treat Parkinson

Question 3

Phenoxybenzamine (PBZ)

Answer 3

α antagonist, inhibits reuptake NE, irreversible, t1/2 1 day, affinity α1>α2, blocks histaminergic cholinergic serotonergic receptors. decreased peripheral R and BP, increased CO + release NE, tachycardia, inhibits vasoconstriction. Adverse hypotension, tachycardia, unresponsive to hypovolemia, inability to ejaculate. exclusively used for pheochromocytoma

Question 4

Phentolamine

Answer 4

α antagonist, reversible, non-selective, t1/2 45 min via IV, similar to PBZ, treat short term BP control and hypertensive crisis. TX: hypotension, tachycardia

Question 5

Prazosin

Answer 5

α1 selective antagonist (1000 fold increase affinity), reversible, t1/2 3 hrs, fall in peripheral R and venous return, relaxes prostate smooth muscle, decrease LDL increase HDL, treat hypertension. Adverse hypotension, syncope

Question 6

Terazosin

Answer 6

α1 selective antagonist. Prazosin congener but more water soluble, higher bioavailability, t1/2 9-12 hrs. treat BPH, hypertension. met. by liver. Adverse postural hypotension

Question 7

Doxasosin

Answer 7

α1 selective antagonist. similar to Terazosin but t1/2 22 hrs. treat hypertension, BPH. met. by liver

Question 8

Tamsulosin

Answer 8

α1 selective antagonist. reversible, high bioavailability, t1/2 5-15 hrs, met. by liver, prevent prostate contraction, treat BPH, less likely to cause postural hypotension. Adverse abnormal ejaculation

Question 9

Yohimbine

Answer 9

α2 selective antagonist, little clinical value, treat orthostatic hypotension, formerly treated ED. Adverse tremor, anxiety

Question 10

Propanolol

Answer 10

β non-selective antagonist. t1/2 3-6 hrs, no sympathomimetic activity, local anesthetic effects, highly lipophilic, oral admin well absorbed, subject to first pass effect, decreased HR + BP + renin. mild CNS effects. treat hypertension, angina, arrhythmia, myocardial infarction, migraine

Question 11

Timolol

Answer 11

β non-selective antagonist. t1/2 4-5 hrs, less lipid soluble than propanolol, no local anesthetic. treat hypertension, angina, migraine, glaucoma

Question 12

Pindolol

Answer 12

β non-selective antagonist. t1/2 3-4 hrs, partial agonist at β1/2. less reduction HR, preferred for hypertension treatment in bradycardia patients

Question 13

Atenolol

Answer 13

β1 selective antagonist. 2nd gen., cardioselective, t1/2 6-9 hrs, very hydrophilic, no CNS no anesthetic no sympathomimetic. treat hypertension angina arrhythmia. caution with asthma

Question 14

Metoprolol

Answer 14

β1 selective antagonist. 2nd gen., cardioselective, t1/2 3-4 hrs, first pass effect, no sympathomimetic, local anesthetic at high doses. treat hypertension, mild HF, arrhythmia. caution with asthma

Question 15

Esmolol

Answer 15

β1 selective antagonist. 2nd gen., cardioselective, t1/2 10 min, no local anesthetic. emergency treatment of supraventricular tachycardia, thyrotoxicosis arrhythmia, preoperative hypertension

Question 16

Labetalol

Answer 16

β non-selective antagonist, 3rd gen., t1/2 4-6 hrs, competitive at α1, sympathomimetic at β2, inhibits reuptake NE (cocaine like), extensive first pass effect, vasodilation. treat hypertension.

Question 17

Carvediol

Answer 17

β non-selective antagonist, 3rd gen., t1/2 7-10 hrs, no sympathomimetic, vasodilation, antioxidant. treat hypertension, CHF, myocardial ischemia