Chapter 45: Calcium Channel Blockers Flashcards
Nifedipine, amiodipine, diltiazem, and verapamil are all in what class of drugs? What are their actions in the body?
These are all calcium channel blockers.
They all work on arterioles and are all anti-hypertensives. They are all used in the treatment of angina.
Nifedipine and amiodipine do what specifically?
The “ipine” Calcium Channel Blockers all work to block channels in the vascular smooth muscle and lower BP. They have NO effect on the heart and will cause reflex tachycardia. Amiodipine is a selective CCB in blood vessels.
What are diltiazem and verapamil used to treat in addition to HTN and angina?
Verapamil and diltiazem work to block calcium channels in both the heart and VSM.
What are the most common adverse side effects of the calcium channel blockers?
constipation, dizziness, flushing, headache, and edema of the ankles and feet.
What happens with overdose of calcium channel blockers? What drugs might be used to counteract this?
Overdose of calcium channel blockers causes severe hypotension and cardiotoxicity (bradycardia, AV block, and ventricular tachydysrhythmias).
Drug to treat this:
IV calcium: to help counteract excessive vasodilation and reduced myocardial contractility.
IV norepinephrine: to raise BP
Atropine and glucagon: to address bradycardia and AV block.
Lower HOB below foot level.
What makes nifedipine different from diltiazem and verapamil:
Nifedipine does not reduce AV conductivity, contractile force, or automaticity. It is not used to treat dysrhythmias. Because of this, Nifedipine does not have the same adverse effects of exacerbating AV block, sick sinus syndrome, or heart failure. It does NOT intensify digoxin induced AV block, cardiosuppression on beta blockers not does it cause constipation.
**Verapamil and diltiazem act on both heart and arterioles, while Nifedipine works on just the arterioles and not the heart.
Does verapamil cause reflex tachycardia? is it combined with a beta blocker? Is diltiazem combined with a beta blocker>
No, verapamil does not cause reflex tachycardia nor should it be combined with a beta blocker due to bradycardia and less contractility.
Diltiazem should NOT be combined with a beta blocker due to increased risk of bradycardia and contractility.
What is reflex tachycardia? Which class of drugs might be used to offset the reflex tachycardia caused by calcium channel blockers like nifidipine?
Reflex tachycardia is an increased heart rate that occurs as the result of stimulation of some type. Typically, this can occur with certain drug administration. Drugs used to offset the reflex tachycardia belong to dihydropyridines.
Why must caution be employed when using a beta blocker with a calcium channel blocker
Caution must be exerted when combining a beta blocker with a calcium channel blocker as certain beta blockers will decrease the adverse cardiac effects of Nifedipine while increasing the adverse cardiac effects of verapamil and diltiazem.
What happens when verapamil is given to a patient taking Digoxin?
Verapamil combined with Digoxin will increase the risk of AV block. This drug also raises the blood plasma level of digoxin.
