Calcium Channel Blockers Flashcards
Calcium Channel Blockers
Therapeutic uses
Calcium channel blockers slow and relax the heart.
Hypertension
Angina Pectoris
Tachycardia
Why are extended release calcium blockers preferred?
They are safer. Immediate release may cause hypertension
Calcium blockers cause vaso_____ of the arteries
Calcium blockers cause vasodilation
What effect do calcium blockers have on veins?
No significant effect on veins
Verapamil & Diltiazem
Effect on heart muscle
-Decrease force of heart’s contracting, rate of firing and electrical conductiont, HR
What makes nifedipine unique / different from verapamil and diltiazem?
-No effect on the heart
-Acts primarily on arterioles,
whereas verapamil and diltiazem act on both arterioles and the heart
What are the 5 hemodynamic effects of Verapamil and Diltiazem?
1) Blockade at peripheral arterioles - reduces arterial pressure
2) Block at arteries and arterioles of the heart - increases coronary perfusion
3) Blockade at SA node - reduces heart rate
4)Blockade at AV node decreases AV nodal conduction
5) Blockade in the myocardium - decreases the force of contraction
Net effects of Verapamil and Diltiazem
Little to no net effect on cardiac performance
Verapamil & Diltiazem
Therapeutic uses
-Angina Pectoris
-Hypertension
-Dysrhythmias - atrial flutter, atrial fibrillation, paroxysmal supraventricular tachycardia
Verapamil & Diltiazem
Adverse effects
-Constipation (less with diltiazem)
-Dizziness, headache, facial flushing
-Heart block (excessive stoppage at the AV node; HR in the 40s)
Verapamil & Diltiazem
Drug interactions
Digoxin
Beta-blockers
Verapamil toxicity
-Hypotension
-Bradycardia and AV block
Verapamil toxicity antidote
Calcium gluconate, norepinephrine, sometimes high dose insulin
IV verapamil for dysrhythmias can cause severe ________ ________
cardiovascular effects
How do you monitor a patient receiving IV verapamil?
ECG should be monitored with resuscitation equipment immediately available
Lowered BP activates the _____ reflex, which causes HR to go up
baroreceptor
How does nifedipine affect HR?
Lowers BP -> activates baroreceptor reflex -> increases HR
Reflex tachycardia
Nifedipine
Therapeutic Uses
Angina pectoris
Hypertension
Nifedipine
Adverse effects
Flushing
Dizziness
Headache
Reflex tachycardia
What can be combined with nifedipine to prevent reflex tachycardia?
Beta blocker (e.g. metoprolol)
Which is preferred - rapid-acting or extended release nifedipine?
Extended release is preferred.
Rapid-acting has been associated with increased mortality in patients with MI and unstable angina
Amlodipine is most similar to ____
nifedipine
