Calcium Channel Blocker Therapy

A patient with hypertension is prescribed amlodipine. The patient asks the nurse, "Why do I only take it once a day?" Which nursing response is appropriate?

"Amlodipine has a long half-life so it is only needed once a day." The rationale for once-a-day dosing is because of the long half-life of amlodipine. Amlodipine has a half-life of 30 to 50 hours and is effective with once daily dosing.

Which patient statements require further nursing action?

"I take my beta blocker with my verapamil so I don't forget." "I take my verapamil when I drink my morning grapefruit juice."

A patient taking a newly prescribed calcium channel blocker states, "I can't seem to get my shoes to fit. My feet feel puffy." Which nursing response is appropriate?

"I will call the health care provider because you may need a diuretic."

Which teaching would the nurse include for a patient who is being discharged home from an acute care setting on a calcium channel blocker?

"Record each angina attack in a journal." Assess your heart rate before taking your medication." Do not chew or crush the sustained-release medication." "Keep a daily record of your blood pressure."

The nurse administers a prescribed dose of amlodipine to a patient at 0800 on Monday. At which time would the nurse anticipate the onset of this medication?

0800 on Tuesday Tuesday at 0800 is within the time that the nurse would anticipate the antihypertensive effect because the onset is within 24 to 48 hours of the first dose.

Interactions with Calcium Channel Blockers adrenergic blockers

Adrenergic blockers can increase the adverse effects of verapamil and diltiazem. Beta blockers are sometimes combined with nifedipine to prevent reflex tachycardia.

The nurse is teaching a course on calcium channel blockers. Which description of the mechanism of action will the nurse provide?

Calcium channel blockers prevent contraction of smooth muscle and allow dilation of the coronary arteries.

The nurse is teaching about nondihydropyridine calcium channel blockers. Which medication would the nurse include?

Diltiazem

Which adverse reactions of amlodipine could Ms. James experience?

Flushing Headache Peripheral edema Rash

Calcium Channel Blockers general teaching

Instruct patients to always take CCBs as prescribed. Teach patients to consult with the primary health care provider prior to stopping the drug. Suddenly stopping the drug can cause rebound hypertension, which can result in damage to heart muscle. Recommend that patients measure weight daily. Teach patients to change positions slowly because syncope (dizziness, lightheadedness) may occur with use of CCBs. Instruct patients to swallow sustained-release formulations whole, without crushing or chewing. Teach patients to increase fluid and fiber in their diet because constipation is a common side effect of verapamil. Instruct patients to avoid grapefruit and grapefruit juice because this can lead to drug toxicity and can affect the metabolism of nifedipine.

The nurse is caring for a patient who is receiving prescribed digoxin and diltiazem. Which assessment data alerts the nurse to a potential interaction?

Irregular heart rate

Which patient assessment data indicates additional teaching by the nurse is required for Ms. James?

Ms. James reports eating grapefruit for breakfast each morning on her new diet. Grapefruit can interfere with the absorption of calcium channel blockers (CCBs) producing higher than normal levels of the drug in the bloodstream. This indicates additional teaching is required for Ms. Jones.

The charge nurse is teaching a class of nurses about nifedipine. Which teaching would the charge nurse include?

Nifedipine blocks calcium channels in vascular smooth muscle. The nurse would include this teaching because nifedipine does block calcium channels in vascular smooth muscle.

Dihydropyridines side effects

Nifedipine is a very potent CCB, and as such, hypotension is more likely to occur. Side effects of nifedipine include flushing, dizziness, headache, peripheral edema, gingival hyperplasia, and a rash in older adults. Reflex tachycardia is an adverse effect that can occur with nifedipine. Reflex tachycardia occurs when the heart rate increases in response to the vasodilation imposed by the drug. To prevent this adverse effect, nifedipine can be combined with a beta blocker. The most common side effects of amlodipine are peripheral and facial edema. Other side effects are similar to all CCBs with flushing, dizziness, headache, and rash in the older adult.

Interventions and Evaluation for Calcium Channel Blockers

Nurses need to assess baseline heart rate and blood pressure and anticipate that blood pressure will decrease with therapy. If hypotension or bradycardia occurs, the nurse may need to hold the medication and notify the health care provider. In older adult patients, nifedipine and amlodipine can cause a rash that mimics eczema; therefore the skin should be assessed for new onset of a rash. Monitor carefully for the development of edema because peripheral edema can occur with this medication; it can be reduced by combining a diuretic with CCB therapy, if necessary.

Calcium Channel Blockers determine baseline data

Obtain baseline blood pressure and heart rate for patients prescribed CCBs. Assess liver and kidney function.

Pharmacodynamic Profile verapamil

Onset: Oral (PO) Variable; Intravenous (IV) 3 min Peak: PO 3 to 4 hr; IV 3 to 5 min Duration: PO 17 to 24 hr; IV 10 to 20 min Half-life: PO 3 to 7 hr; IV 2 to 5 hr

Pharmacodynamic Profile nifedipine

Onset: PO 20 min; IV 1 min Peak: PO 1 to 2 hr; IV 45 min Duration: PO 8 hr Half-life: PO 2 to 5 hr

Pharmacodynamic Profile dilitiazem

Onset: PO 30 to 60 min; IV bolus within 3 min Peak: PO 2 to 3 hr Duration: PO 4 to 12 hr; IV bolus 1 to 3 hr; after discontinuation of continuous IV infusion, duration is 0.5 to 10 hr Half-life: 3.5 to 9 hr

Amlodipine dosage

PO 2.5-5 mg/day initially; max 10 mg/day given for hypertension

Diltiazem dosage

PO 30 mg three times a day Extended-release: PO 120 to 240 mg/day Sustained-release: PO 60 mg twice a day given for hypertension

Verapamil dosage

PO 80 mg three times a day, may titrate upward Extended-release: PO 120 to 240 mg/day as single dose given for Hypertension

Nifedipine dosage

PO extended-release 30-60 mg/day; can be titrated up as needed, maximum depends on the formulation given for hypertension

Calcium Channel Blockers identify high-risk patients

Patients with low blood pressure, those with second- and third-degree atrioventricular (AV) block, and those with sick sinus syndrome (in the absence of pacing) should not be given CCBs. Patients with heart failure, renal disease, and liver disease require special caution. Patients receiving digoxin and beta blockers also require special consideration and monitoring (especially with the use of verapamil and diltiazem).

Calcium Channel Blockers side effects

Teach patients that side effects of CCBs are due to vasodilation. Instruct patients that headache, dizziness, and peripheral edema are common side effects of CCBs.

Calcium Channel Blockers self monitoring

Teach patients the signs and symptoms of edema. Instruct patients to notify the health care provider if they experience swelling in the ankles and feet. Instruct patients to notify the health care provider of cardiac effects of CCBs. Shortness of breath, weight gain, and a slower-than-normal heart rate are effects that should be reported. Teach patients how to assess their heart rate. Teach patients about the importance of checking their blood pressure and how to maintain an accurate blood pressure record. Instruct patients taking CCBs for angina to keep a record of angina attacks, including when they occur, the severity, and circumstances of the attacks. The health care provider should be notified if attacks increase. Teach patients that alcohol can affect the way that CCBs work and can cause severe side effects. Patients should avoid alcohol.

The nurse administers a prescribed dose of intravenous verapamil to a patient with a baseline blood pressure (BP) of 210/110 mm Hg at 0800. Which BP reading would the nurse expect to see 15 minutes after administration?

The BP will start to increase, returning to baseline within 10 to 20 minutes.

Interactions with Calcium Channel Blockers digoxin

The use of verapamil or diltiazem with digoxin can cause partial or complete AV block. Nurses should monitor the patient for slowed heart rate and skipped heart beats. Digoxin dose may need to be reduced because CCBs can cause increased blood levels of digoxin.

Interactions with Calcium Channel Blockers grapefruit juice

Toxicity can result if verapamil and diltiazem are administered with grapefruit juice. Grapefruit juice affects absorption and can raise levels of verapamil and diltiazem in the bloodstream.

A patient who is taking sustained-release diltiazem is having difficulty swallowing the medication. What teaching is appropriate?

Try swallowing the medication whole in pudding or applesauce.

Interactions with Calcium Channel Blockers beta blockers

Use of verapamil or diltiazem with beta blockers increases the chance of bradycardia. Combination use of verapamil and diltiazem with beta blockers can also cause AV block and heart failure. Patients should be closely monitored for changes in heart rate. Verapamil (administered intravenously) and beta blockers should be administered several hours apart.

Nondihydropyridines side effects

Verapamil is usually tolerated well. The most common side effect is constipation. Adverse effects include bradycardia as well as blockages in cardiac conduction. Verapamil should not be used in patients with sick sinus syndrome or second- or third-degree heart block. Diltiazem has similar side and adverse effects as verapamil. The side effect of constipation is not as common with diltiazem as it is with verapamil.

CCBs are contraindicated with

a known drug allergy. This class of drugs is also contraindicated in acute myocardial infarction (MI). CCBs are also contraindicated in AV heart block (second- and third-degree) and sick sinus syndrome (unless the patient has a pacemaker). Because of exclusive metabolism in the liver, verapamil and diltiazem are contraindicated in patients with liver failure. Verapamil and diltiazem work rapidly to decrease blood pressure and should not be administered to patients with hypotension.

Nifedipine is used for

angina and hypertension. It is not used to treat dysrhythmias because it has minimal calcium blockage in the heart.

Diltiazem is used for

angina, hypertension, and cardiac arrhythmias. Commonly used in IV form for the treatment of atrial fibrillation and flutter.

The primary uses for verapamil include

angina, hypertension, and cardiac dysrhythmias.

The nurse will evaluate the effects of CCBs by

assessing for a therapeutic effect of the drug. Blood pressure should be monitored routinely with the expectation to reduce systolic/diastolic pressure to below 130/80 mm Hg.

Verapamil blocks

calcium channels in blood vessels and the heart. This produces relaxation of coronary smooth muscle and dilation of coronary arteries.

Nifedipine blocks

calcium channels in the vascular smooth muscle, promoting vasodilation. There is minimal blockade to calcium channels in the heart.

Verapamil metabolism

in the live

Amlodipine metabolism

in the liver

Diltiazem metabolism

in the liver

Nifedipine metabolism

in the liver

Amlodipine excretion

in urine

Verapamil excretion

in urine

Diltiazem excretion

in urine and feces

Nifedipine excretion

in urine and feces

Nifedipine distribution

protein bound

Diltiazem distribution

protein bound 70- 80 %; in breast milk

Verapamil distribution

protein bound 90%

Amlodipine distribution

protein bound; crosses placenta; in breastmilk

CCBs cause

smooth muscle relaxation by preventing calcium from entering cells and connecting to receptors. This prevents contraction. CCBs relax the smooth muscle surrounding the heart and cause the coronary arteries to dilate. This action increases blood flow to the heart and increases oxygen supply. CCBs are considered first-line treatment for angina, cardiac dysrhythmias, and hypertension.

There are only two nondihydropyridines

verapamil and diltiazem. The other CCBs are all dihydropyridines and end in -pine (nifedipine, amlodipine, felodipine). This helps in differentiating CCBs.

Diltiazem works very similar to

verapamil by blocking calcium channels in the heart and blood vessels, producing relaxation of coronary smooth muscle and dilation of coronary arteries.

Amlodipine absorption

well absorbed

Diltiazem absorption

well absorbed

Nifedipine absorption

well absorbed

Verapamil absorption

well absorbed