Overview
This lecture covers the main uses, mechanisms, examples, side effects, and precautions related to calcium channel blockers as antihypertensive medications.
Uses of Calcium Channel Blockers
- Primarily used to treat hypertension (high blood pressure) and angina (chest pain).
- Also effective for dysrhythmias (irregular heartbeats), migraine headaches, and Raynaud's disease.
Mechanism of Action
- Cause relaxation of smooth muscle in blood vessels.
- Decrease peripheral smooth muscle tone and systemic vascular resistance.
- Result in lowered blood pressure.
Common Drug Names
- Drug names typically end with the suffix "-pine," such as nifedipine and amlodipine.
Adverse Effects
- May cause reflex tachycardia (increased heart rate in response to lowered blood pressure).
- Can lead to orthostatic hypotension (blood pressure drops upon standing).
- Risk of causing or worsening dysrhythmias.
Contraindications & Interactions
- Should not be taken with grapefruit juice due to increased risk of toxicity.
- Avoid combining with drugs like verapamil or diltiazem to prevent toxic effects.
Key Terms & Definitions
- Calcium Channel Blocker — Medication that blocks calcium channels, relaxing blood vessel muscles and lowering blood pressure.
- Angina — Chest pain due to reduced blood flow to the heart.
- Peripheral Vascular Resistance — Resistance in blood vessels outside the heart affecting blood pressure.
- Reflex Tachycardia — Compensatory increase in heart rate after lowered blood pressure.
- Orthostatic Hypotension — Drop in blood pressure when standing up.
Action Items / Next Steps
- Review specific calcium channel blocker drug names ("-pine" suffix).
- Memorize contraindications, especially with grapefruit juice and other calcium channel blockers.