Pharmacology - Calcium Channel Blockers

At therapeutic doses, what effect do calcium channel blockers have on the veins?

No significant effect

Calcium channel blockers selectively act on

peripheral arterioles and arteries

General suffix for calcium channel blockers

-pine

Calcium channel blockers that don’t fit normal naming scheme

verapamil, diltiazem

Dihydropyridines act primarily on

arterioles

Verapamil and diltiazem act on

arterioles and the heart

Verapamil and diltiazem can cause these hemodynamic effects, especially in first doses

reflex tachycardia and/or hypertension

Verapamil is used for

vasospastic angina, effort angina, essential HTN, dysrhythmias, migraine

Most common side effect of verapamil

constipation

Less common side effects of verapamil may include

dizziness, facial flushing, HA, peripheral edema, gingival hyperplasia (overgrowth of gum tissue), heart block

Verapamil can have adverse interactions with these drugs

digoxin and beta blockers

S/S verapamil toxicity

severe hypotension

bradycardia and AV block

ventricular tachydysrhythmias

Treatment for verapamil toxicity

gastric lavage, activated charcoal if given PO

fluids if given IV

These special precautions must be used if patient is receiving IV verapamil for dysrhythmias

BP and ECG should be monitored

Resuscitation equipment should be kept immediately available

Diltiazem therapeutic uses

Angina, HTN, cardiac dysrhythmias

Diltiazem has similar side effects to verapamil, except for

decreased risk of constipation

Diltiazem should not be given if the patient has

Bradycardia, sick sinus syndrome, heart failure, or second- or third-degree heart block 

Diltiazem can have adverse interactions with these drugs

digoxin, beta blockers

Unlike other calcium channel blockers, dihydropyridines cannot be used to treat

dysrhythmias

Reflex tachycardia/hypertension may be seen with initial doses of this form of nifedipine

immediate release

Adverse effects of nifedipine

Flushing, dizziness, HA, peripheral edema, gingival hyperplasia, chronic eczematous rash in older adults

Patient is to receive a scheduled dose of diltiazem. The nurse should hold the medication and contact the prescriber if which of the following is noted?

The patient is in second-degree heart block