Pharmacology II: Calcium Channel Blockers

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary indication for the use of calcium channel blockers?

Long-term prevention of angina (correct)

Treatment of cardiac arrhythmias

Short-term relief of chest pain

Treatment of hypertension

What is the effect of calcium channel blockers on the heart's contractions?

Decrease the force of the heart's contractions (correct)

Increase the force of the heart's contractions

Have no effect on the heart's contractions

Increase the heart rate

What is the effect of calcium channel blockers on arterioles?

They have no effect on arterioles

They prevent arterioles from constricting (correct)

They cause arterioles to constrict

They increase the diameter of arterioles

What is the effect of calcium channel blockers on oxygen demand of the heart?

They decrease the oxygen demand of the heart Signup and view all the answers

What is the effect of calcium channel blockers on the heart rate?

They decrease the heart rate Signup and view all the answers

What is the bioavailability of calcium channel blockers after oral administration?

Low due to high first-pass effect Signup and view all the answers

What is the effect of calcium salts and vitamin D on calcium channel blockers?

They reduce the effectiveness of calcium channel blockers Signup and view all the answers

What is the mechanism of action of calcium channel blockers?

They prevent the passage of calcium ions Signup and view all the answers

What is a potential adverse reaction that verapamil and diltiazem can cause?

Hypotension Signup and view all the answers

What should be monitored regularly during therapy with verapamil or diltiazem?

Pulse rate and blood pressure Signup and view all the answers

What should be done before giving the drug to a patient?

Measure the apical pulse rate and blood pressure Signup and view all the answers

What is a key nursing diagnosis for a patient taking verapamil or diltiazem?

Risk for injury related to orthostatic hypotension Signup and view all the answers

What should be done if the patient's systolic pressure is below 90 mmHg or their heart rate drops below 60 beats/minute?

Withhold the dose and notify the prescriber Signup and view all the answers

What is an important aspect of patient education when taking verapamil or diltiazem?

How to manage adverse reactions Signup and view all the answers

Why should the patient be assisted with ambulation during the start of therapy?

Because of the risk of dizziness Signup and view all the answers

What should be done with sustained-release tablets?

Don't crush them Signup and view all the answers

Study Notes

Calcium Channel Blockers

Used to prevent angina that doesn't respond to other antianginal classes, as well as antiarrhythmics and in the treatment of hypertension.
Examples of calcium channel blockers include amlodipine besylate, diltiazem, nicardipine, nifedipine, and verapamil.

Pharmacokinetics

Absorbed quickly and almost completely when administered orally.
Bioavailability is lower due to the first-pass effect.
Highly bound to plasma proteins.
Metabolized rapidly and almost completely in the liver.

Pharmacodynamics

Prevent the passage of calcium ions across the myocardial cell membrane and vascular smooth-muscle cells.
Causes dilation of the coronary and peripheral arteries, decreasing the force of the heart's contractions and reducing the workload of the heart.
Reduces afterload, resulting in a decreased oxygen demand of the heart.
Some calcium channel blockers (diltiazem and verapamil) also reduce the heart rate by slowing conduction through the SA and AV nodes.

Pharmacotherapeutics

Used only for long-term prevention of angina, not for short-term relief of chest pain.
Particularly effective for preventing Prinzmetal's angina.

Drug Interactions

Calcium salts and vitamin D reduce the effectiveness of calcium channel blockers.
Verapamil and diltiazem increase the risk of digoxin toxicity and enhance the action of carbamazepine.

Adverse Reactions

Headache
Dizziness
Weakness
Orthostatic hypotension
Heart failure
Hypotension
Peripheral edema
Palpitations
Arrhythmias such as tachycardia, bradycardia, and AV block (also occur with diltiazem and verapamil)

Assessment

Obtain a history of the patient's underlying condition before therapy and reassess regularly.
Obtain a baseline blood pressure and pulse rate and rhythm; recheck regularly.
Monitor the ECG when therapy starts and when the dosage is adjusted.
Monitor the patient's vital signs frequently and assess for signs of toxicity and adverse reactions.

Key Nursing Diagnoses

Risk for injury related to orthostatic hypotension.
Risk for injury related to adverse reactions.
Deficient knowledge related to drug therapy.

Planning Outcome Goals

Risk for injury will be minimized.
Complications from adverse reactions will be diminished.
The patient will verbalize an understanding of drug therapy.

Implementation

Don't crush sustained-release tablets.
Be aware that sustained-release and extended-release medications aren't interchangeable.
Take safety precautions if adverse CNS reactions occur.
Withhold the dose and notify the prescriber if the patient's systolic pressure is below 90 mmHg or their heart rate drops below 60 beats/minute.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the properties and uses of calcium channel blockers in Pharmacology II. It includes their application in preventing angina and hypertension, as well as their role as antiarrhythmics.