Calcium Channel Blockers (CBB)

Question 1

What are calcium channel blockers used to treat?

Answer 1

Hypertension for now

Contraindicated in heart failure!

Question 2

Where do calcium channel blockers act?

Answer 2

These drugs bind to the L-type calcium channels in cardiac and vascular smooth muscle -> Lead to muscle relaxation

Question 3

How do calcium channel blockers exhibit their therapeutic effect? (just for clarity)

Answer 3

L-type calcium channels are responsible for excitation-contraction coupling of skeletal, smooth, and cardiac muscle and for hormone secretion in endocrine cells. In the heart they are also involved in the conduction of the pacemaker signals. CCBs used as medications primarily have three effects:

1. Acting on vascular smooth muscle they reduce contraction of the arteries and cause an increase in arterial diameter, a phenomenon called vasodilation (CCBs do not work on venous smooth muscle)
2. Acting on cardiac muscles (myocardium), they reduce the force of contraction of the heart
3. Slowing down the conduction of electrical activity within the heart, they slow down the heart beat.

Question 4

Name the two broad classes of calcium channel blockers.

Answer 4

Non-dihydropyridines (non-DHPs) and dihydropyridines (DHPs)

Question 5

T/F. All dihydropyridines (DHPs) agents end with -dipine?

Answer 5

True

Question 6

Name the two non-DHP calcium channel blockers.

Answer 6

Verapamil and diltiazem

Question 7

Name the DHP calcium channel blocker.

Answer 7

Nifedipine

Question 8

Verapamil

Answer 8

Significant cardiac depression (Dec HR, dec. myocardial contractility, dec. nodal conduction)

Less affect on resistance vessels (Inc. peripheral vasodilation, inc. renal blood flow)

Question 9

Diltiazem

Answer 9

Both cardiac and vessels (Dec HR, dec. myocardial contractility, dec. nodal conduction)

More cardiac depression than affect on resistance vessels (Inc. peripheral vasodilation, inc. renal blood flow)

Question 10

Nifedipine

Answer 10

Mainly arteriole vasodilatation (Dec TPR -> Can lead to reflex tachycardia, Inc HR)

Little affect on cardiac muscle

Question 11

Adverse affects of non-DHP calcium channel blockers.

Answer 11

1. Constipation (esp with non-DHPs such as verapamil)

2. Cardiac depression and bradycardia with non-DHPs

Question 12

What class of drugs is contraindicated with non-DHPs (Verapamil, Diltiazem)?

Answer 12

Beta-blockers

Question 13

Adverse affects of DHP calcium channel blockers.

Answer 13

1. Hypotension
2. Reflex tachycardia
3. Flushing
4. Headache
5. Edema
6. Gingival hyperplasia

Question 14

Name the three calcium channel blocker medications that can cause gingival hyperplasia.

Answer 14

1. Nifedipine (10%)
2. Dilantin (for seizures) (40%)
3. Cyclosporine (Immunosuppressant) (30%)

Question 15

In this category of antihypertensive agents (Ca channel blockers) there are 3 drugs to know. Name the three starting with the one with the most CARDIAC action and progressing to the most ARTERIOLE action.

Answer 15

Verapamil (significant cardiac depression)

Diltiazem (more cardiac than resistance vessels)

Nifedipine (Mainly arteriole vasodilation)