From the Guidelines
No, calcium channel blockers cannot be deposited into coronary arteries. Calcium channel blockers are oral or intravenous medications that work systemically by binding to calcium channels in vascular smooth muscle and cardiac cells, not by direct deposition into arterial walls. Common calcium channel blockers include amlodipine, diltiazem, nifedipine, and verapamil. These medications function by preventing calcium from entering cells, which causes vasodilation and reduces blood pressure, vascular resistance, and cardiac workload. Unlike certain substances such as calcium or cholesterol that can accumulate in arterial walls forming plaques, these medications circulate in the bloodstream and bind to specific receptor sites on cell membranes. The confusion may arise because calcium channel blockers are often prescribed to treat coronary artery disease, but they work by affecting the function of the arteries rather than being physically deposited within them. Their therapeutic effect comes from improving blood flow through coronary arteries by relaxing the arterial smooth muscle, not by structural changes to the vessel walls 1.
Key Points
- Calcium channel blockers are not deposited into coronary arteries
- They work systemically by binding to calcium channels in vascular smooth muscle and cardiac cells
- Common calcium channel blockers include amlodipine, diltiazem, nifedipine, and verapamil
- They function by preventing calcium from entering cells, causing vasodilation and reducing blood pressure, vascular resistance, and cardiac workload
- Their therapeutic effect comes from improving blood flow through coronary arteries by relaxing the arterial smooth muscle, not by structural changes to the vessel walls
Mechanism of Action
Calcium channel blockers reduce cell transmembrane inward calcium flux, which inhibits both myocardial and vascular smooth muscle contraction; some also slow AV conduction and depress sinus node impulse formation 1. Agents in this class vary in the degree to which they produce vasodilation, decreased myocardial contractility, AV block, and sinus node slowing.
Clinical Use
Calcium channel blockers may be used to control ongoing or recurring ischemia-related symptoms in patients who already are receiving adequate doses of nitrates and beta blockers, in patients who are unable to tolerate adequate doses of 1 or both of these agents, and in patients with variant angina 1. Rapid-release, short-acting dihydropyridines (e.g., nifedipine) must be avoided in the absence of concomitant beta blockade because of increased adverse potential. Verapamil and diltiazem should be avoided in patients with pulmonary edema or evidence of severe LV dysfunction. Amlodipine and felodipine are reasonably well tolerated by patients with mild LV dysfunction.
From the Research
Calcium Channel Blockers in Coronary Arteries
- Calcium channel blockers can be used to treat hypertension and angina in patients with coronary artery disease 2, 3, 4.
- These medications work by lessening the rate of calcium ion entry through voltage-gated L-type channels, which helps to reduce blood pressure and alleviate angina symptoms 5.
- The efficacy of calcium channel blockers in treating hypertensive patients with previous stroke and/or coronary artery disease has been assessed in several studies, with results showing that they are at least as efficacious as other classes of antihypertensive medications in lowering blood pressure 6.
Benefits and Risks
- Calcium channel blockers have been shown to reduce the risk of coronary revascularization and hospitalization for angina in patients with coronary artery disease 3, 4.
- However, they may also increase the risk of congestive heart failure in certain patients 6.
- The use of long-acting, lipophilic calcium channel blockers has been associated with a reduced risk of coronary heart disease outcomes, whereas short-acting formulations may increase this risk 4.
Treatment Guidelines
- Calcium channel blockers are recommended as alternative treatments for patients with coronary artery disease who cannot tolerate beta blockers or angiotensin-converting enzyme inhibitors 2.
- They can be used in combination with other medications, such as nitrates, to treat anginal symptoms 2.
- The choice of calcium channel blocker and dosage should be individualized based on the patient's specific needs and medical history 5.