Calcium channel blockers-by Dr Harold Gunatillake

Dr Harold Gunatillake

Transcript: Do you know what calcium channel blockers are?

Most of you may be on a calcium channel blocker, prescribed by your family physician, without your knowing, for High Blood Pressure (essential hypertension).

They are also called calcium antagonists, given for the treatment of a variety of conditions, such as high blood pressure, migraine and Raynaud’s disease (peripheral arterial spasm).

Calcium is required by the heart muscles and other blood vessels for efficient contraction movement. So blocking such a mechanism or inhibiting transport of calcium into cells will lower the blood pressure and widen blood vessels by affecting the muscle cells in the arterial walls, especially those of the coronary arteries.

These calcium antagonists also tends to slow the heart rate which is also beneficial in situations where not only the blood pressure but also the heart rate needs to be slowed down for efficient muscle contractions and prevent premature aging of the muscle cells of the heart.

By such action the blood pressure is lowered chest pain (angina) is relieved and also corrects irregular heart -beat.

Some calcium channel blockers are available in short- acting forms, and others long- acting forms. The quick acting ones act quickly and the effects last only a few hours, while the long-acting medications are slowly released to provide a longer lasting effect.

Examples of calcium channel blocking medication available include:

Amlodipine (Norvasc)
Diltiazem (Cardizem)
Felodipine (Plendil)
Isradipine (DynaCirc SR)
Nifedipine (Adalat CC)
Nisoldipine (Sular)
Verapamil ( Calan Verelan

These drugs are normally prescribed in combination with other anti-hypertensive drugs. These calcium channel blockers are beneficial to prevent or improve symptoms in a variety of conditions, including

High blood pressure
Chest pain due to angina
Migraine headaches
Brain aneurysm complications
Irregular heart beats
Circulatory conditions like Raynaud’s disease

Effect on kidneys

Studies suggest that calcium channel blockers do not worsen the progression of renal disease but may rather provide benefit when systemic blood pressure has been tightly normalized.

Side effects of these medications are:

Constipation-(beware of verapamil). Increase your fibre content and drink plenty of water)
Headache-(due to widening of arteries)
Rapid heart rate
Rash
Drowsiness
Flushing- (due to widening and relaxing of arteries)
Nausea
Swelling of legs and feet (pitting oedema due to water retention).

Serious side effects are rare, and it is not wise to stop calcium-channel blockers without speaking to your doctor.

Most people who take these medications have no side –effects, or only minor ones.

These channel blockers should not be taken with grapefruit as they can reduce your liver’s ability to eliminate calcium channel blockers from your body, allowing the medications to build up in your body.

Rebound effect

Some people who suddenly stop taking a calcium-channel blocker have a ‘rebound’ flare up of angina. Therefore, it is best not to stop taking these drugs without first consulting a doctor.

Check your blood pressure weekly until it is stable. Early high blood pressure has no early signs or symptoms as the body
gets accustomed to the slow rising of the blood pressure. Most heart attacks and stroke are preventable if your blood pressure is taken care of.

Hope this article was useful. Stay safe

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