Calcium Channel Blockers

Question 1

Vascular tone affecting factors:
Intrinsic:from—–1——-2——-3—–role—–
Extrinsic:1——2—— from—– Role—-

Answer 1

Intrinsic: from vascular smooth muscle
Regulate blood flow
1-endothelial factors(NO and endothelin)
2-local hormones(arachidonic acid mets, histamine (vc) and bradykinin(vd)
3-metabolic byproducts or hypoxia

Extrinsic: from outside the vessels
Regulates vascular resistance
1-sympeth AGT II
2-ANP VD

Question 2

Calcium channel blockers
Mechanism of action:

Answer 2

Ca2+ influx through L type channel is important determinant of vascular tone and cardiac contractility
Calcium channel blockers block many types of SM but strongest on vascular muscle
They bind to alpha subunit which is the main one in the channel at vascular smooth muscle, cardiac muscle and nodal tissue

Question 3

Effect of CCB;
1-
2-
3-
4-

Answer 3

1-vascular dilation
2-decrease contractility (neg ioni)
3-decrease HR (neg chrono)
4-decrease conduction (neg dromo)

Question 4

Unstable angina is a —— ischemia
Chronic stable angina is ——
Printzmetal’s variant angina——-

Answer 4

Supply ischemia
Demand ischemia
Supply ischemia

Question 5

Slide 14 important

Question 6

Nifedipine:
Derived from:
Main action:
Minimum effect on:
Usage:
MOAd:
Mode of met and excretion:
Adverse effects

Answer 6

Dihydropyridine
Arteriolar vasodilator
Cardiac heart rate or conduction
Tx for angina caused by coronary spasm
Orally short half life
Hepatic, urine and feces
Flushing,headache,hypotension,peripheral edema, constipation,reflex tachy

Question 7

Verapamil:
Derived;
Actions:
Negative iono?
Strong Vadodilator?
Metabolism?
Contraindication?
Side effect?

Answer 7

Phenylalkalamine
Slows conduction,decrease heart rate and contractility BP and oxygen deman
Negative iono better than nifedipine but weaker as a vasodilator
Extensively Hepatic (adjust dose in patient with liver dys)
Contraindicated with patients with depressed cardiac function or AV conduction
Side effect : constipation

Question 8

Diltiazem
Family:
Effects:
Metabolism

Answer 8

Benzothiazepine
Cardiovascular similar of verapamil
Relieve coronary artery spasm(used in patients with variant amgina)
Extensively metabolised by liver

Question 9

T or F
Diltiazem reduces HR better than verapamil

Answer 9

False
Reversed

Question 10

Phamacokinetics of CCB:
ROAd
Bioavailabilty
Onset of action
Distribu;
Half life:
Excretion:

Answer 10

Oral (all) vera and ditia IV
Low due to high first bypass effect (amlodipine have higher bioavail)
30-60 min
(Exc amlodipine the more slowly absorbed the longer acting)
Dis:bound extensively to Plasma protein (70-98)
Vary from 1.3 64 hr (40 hr for amlodipine)
Nife and vera excreted by kidney
Diltiazem excreted by liver

Question 11

T or F
Most of CCB have short half lives (3-8 hr)

Answer 11

True

Question 12

T or F
Amlodipine has shorter half life and require sustained release formulation

Answer 12

False
Long half life
Don’t require sustained release fomulation

Question 13

General uses of CCB
1-
2-
3-

Answer 13

Hypertension
Angina
Diltiazem and verapamil used for TX of AFib

Question 14

T or F
b blockers are most used in patients with hypertension accompanies with asthma,diabetes and peripheral vascular disease

Answer 14

Flase
CCB

Question 15

Adverse effects of CCB:
1-
2
3-
4-
5-

Answer 15

1-AV block and const caused by verapami
2-Vera and diltia are avoided in patients with AV block or HF
3-Dizziness,headache and fatigue due to decrease BP are commonly caused by dihydropyridines
4-peripheral edema
5- dihydropyridines may cause gingival hyperplasia