Calcium Channel Blockers Lecture PDF

Question 1

Blocking Ca2+ channels prevents the inward movement of Ca2+ into the cell, preventing ____ in vascular smooth muscle of ___ and therefore causing ____

Answer 1

contraction, arteries, vasodilation

Question 2

Ca2+ channel blocker activity on the heart (3)

Answer 2

• decreases contractile effect
• decreases speed of conduction of AP in SA and AV node
• Slow heart rate

Question 3

Coupling of cardiac ca2+ channels to B1 adrenergic receptors

Answer 3

Refers to how in the heart the Ca2+ channels are linked to B1 adrenergic receptors, when B1 receptors are activated, Ca2+ influx is enhanced and when blocked, influx is suppressed, therefore Ca2+ channel blockers and B blockers have identical effects on heart

Question 4

3 classifications of ca2+ channel blockers and what can they be used on?

Answer 4

• dihydropyridine (only affect blood vessels)
• phenylakylamine (can be used on blood vessels and heart)
• benzothiazepine (can be used on blood vessels and heart)

Question 5

Verapamil (calan, covera HS, verelan) drug class and mech of action

Answer 5

• phenylakylamine Ca2+ channel blocker
• directly effects heart and blood vessel causing vasodilation, reducing heart rate, AV conduction, and force of contraction, balanced by indirect (reflex) effects of baroreceptors, ultimately resulting in net effect of vasodilation and reduced arterial pressure and increased coronary perfusion

Question 6

Verapamil (calan, covera HS, verelan) therapeutic uses (3)

Answer 6

• angina pectoris (both vasospastic and effort induced)
• essential hypertension (1st line treatment)
• cardiac arrhythmias

Question 7

Verapamil (calan, covera HS, verelan) ADR’s (4)

Answer 7

• constipation frequently due to Ca2+ blockade in small intestine
• edema in ankles and feet
• in cardiac diseased hearts could see bradycardia or AV block (in healthy heart effects are minimal)
• should not be used in patients with sick sinus syndrome or 2nd/3rd degree AV block

Question 8

Verapamil (calan, covera HS, verelan)/Diltiazem (cardizem, dilacor, dilitia XT, tiazac) drug interactions (3)

Answer 8

• digoxin which also suppresses conduction thru AV node could cause large increased risk of AV block
• B 1 antagonists have same effect as verapamil on heart and may risk excessive cardiosuppression
• grapefruit juice

Question 9

Verapamil (calan, covera HS, verelan) toxicity reversal (2)

Answer 9

• atropine

- glucagon

Question 10

Diltiazem (cardizem, dilacor, dilitia XT, tiazac) drug class and therapeutic uses (3)

Answer 10

-Benzothiazepine Ca2+ channel blocker

• angina pectoris
• essential HTN
• cardiac arrhythmias

Question 11

Diltiazem (cardizem, dilacor, dilitia XT, tiazac) ADR’s (3)

Answer 11

• dizziness
• edema of ankles and feet
• exacerbate bradycardia, AV block, CHF

Question 12

Nifedipine (adalat, nifedical, procardia) drug class and mech of action

Answer 12

• Dihydropyridines Ca2+ channel blocker
• blocks Ca2+ channels in VSM promoting vasodilation, produces very little blockade of Ca2+ channels in the heart, cannot treat cardiac arrhythmias, increases coronary artery perfusion, but does not affect AV conduction, contractile force, or automaticity reduction, net effect lowers BP, increases HR, increases contractile force

Question 13

Nifedipine (adalat, nifedical, procardia) therapeutic uses (2)

Answer 13

• angina pectoris (vasospactic and exercise induced) alongside B blocker often to prevent reflex tachycardia
• essential hypertension

Question 14

Nifedipine (adalat, nifedical, procardia) ADR’s (2)

Answer 14

• reflex tachycardia if not used alongside B blocker

- toxic doses can lose selectivity and affect heart

Question 15

Nimodipine (nymalize, nimotop) function

Answer 15

Another type of dihydropyridine that is only capable of producing the Ca2+ blockade in cerebral vessels only approved for prophylaxis of neurologic injury following rupture of intracranial aneurysm