Drug treatments: Calcium channel blockers

Calcium channel blockers have an immediate effect on reducing blood pressure. They work by relaxing and expanding the blood vessels, allowing blood to pass through more easily. However, studies report that they are inferior to other high blood pressure medications in preventing heart attacks, stroke, or kidney complications. They are often more expensive than diuretics or beta-blockers. Some experts now believe they should be used mainly as a second-line agent.

No one should ever stop taking these drugs abruptly, because such action could dangerously increase the risk of high blood pressure.

These drugs include:

• Diltiazem (Cardizem, Dilacor)
• Amlodipine (Norvasc)
• Verapamil (Calan, Isoptin, Verelan)
• Nisoldipine (Sular)
• Nicardipine (Cardene)
• Nifedipine (Adalat, Procardia)
• Isradipine (DynaCirc)
• Lercanidipine (Zanidip)
• Felodipine (Plendil)
• Nitredipine (Cardif, Nitrepin)

Side effects

Side effects vary among different preparations and may include:

• Fluid accumulation in the feet
• Constipation
• Fatigue
• Impotence
• Gingivitis
• Flushing
• Allergic symptoms

Newer drugs, such as lercanidipine, may reduce or avoid many of these side effects.

Grapefruit and Seville oranges (used in some marmalades) may have a harmful interaction with calcium channel blockers, particularly in the elderly.

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