Lecture 14 - Alpha Blockers and Ca Channel Blockers

Question 1

Alpha affinities?

Answer 1

Norepinephrine > Epinephrine&raquo_space; isoproterenol

Question 2

Alpha 1?

Answer 2

post-synaptic, vasoconstriction, alpha1a found in prostate, alpha1b found in vascular smooth muscle

Question 3

Alpha 2?

Answer 3

pre and post synaptic, inhibit norepinephrine and insulin release

Question 4

Alpha 1 antagonism drug?

Answer 4

doxazosin -> vasodilation hypotension

Question 5

Alpha blocker indications?

Answer 5

hypertension (used as combination therapy, not first line), phaeochromocytoma, prostatism

Question 6

Doxazosin?

Answer 6

reversible alpha blocker (1»>2), blocks all subtypes, vasodilator, reduce prostatic symptoms, start low dose and titrate, once daily, liver metabolism, fecal excretion

Question 7

Alpha blocker adverse effects?

Answer 7

hypotension, lassitude, nasal stuffiness, dry mouth, urinary incontinence

Question 8

Phenoxybenzamine?

Answer 8

oral, irreversible alpha blocker antagonism (1 > 2), used in pheaochromocytoma and pre-operatively,

Question 9

Phenoxybenzamine side effects?

Answer 9

decreased postural BP, tachycardia, nasal stuffiness, CNS

Question 10

Alpha and beta combined therapeutics?

Answer 10

Labetalol (reversible, used for hypertension in pregnancy and phaeochromocytoma). Carvedilol (also anti-oxidant, used in congestive cardiac failure)

Question 11

Indications for Ca channel blockers?

Answer 11

hypertension, angina, arrhythmias, vasospasms

Question 12

Ca channel blocker physiology?

Answer 12

block voltage-operated L-type Ca channels of cardiac and smooth muscle, selective for resistance vessels, myocardium and conducting tissue

Question 13

Ca channel blockers - vascular SM mechanism>

Answer 13

decreased tone, resistance and blood pressure/afterload

Question 14

Ca channel blockers - cardiac mechanisms?

Answer 14

decreased contractility, sinus and AV node transmission

Question 15

Ca channel blockers - specific drugs?

Answer 15

nifedipine (vessels - flushing, headaches oedema), diltiazem (both), verapamil (heart an gut - heart block, negative ionotrope, constipation)

Question 16

Ca channel blockers - PK?

Answer 16

hepatic metabolism, short (nifedipine) or long (amlodipine) half life

Question 17

Nifedipine?

Answer 17

used for hypertension & vasospasm, oral, liver metabolism and renal excretion, side effects oedema, flushing and headache, t1/2 few hours

Question 18

Diltiazem?

Answer 18

used for angina, hypertension and tachyarrhythmias (AF), oral, liver metabolised and fecal excreted, side effects oedema, flushing, headache and bradycardia, can b used with beta-blockers

Question 19

Verapamil?

Answer 19

used for tachyarrhythmias (SVT, AF) and hypertension, oral and IV, hepatic metabolism and renal excretion, 7hr t1/2, side effects bradycardia, negative inotrope and constipation

Question 20

Verapamil interactions?

Answer 20

BETA BLOCKERS, inhibits cytc p450, care with statins, inhibits p-glycoproteins