What is a calcium channel?
In medicine when we speak of calcium channels, we are referring to small parts of cells that selectively allow calcium to pass through from the outside to the inside of the cell. In muscle cells this causes the muscle to contract or constrict.
What does a calcium channel blocker do?
A calcium channel blocker will block the movement of calcium through the channel, and therefore the muscle tends to stay in a more relaxed state. When this occurs in the arterial and heart muscles, this allows more blood to flow through the vessels thereby reducing blood pressure and allowing more oxygen.
What are the different calcium channel blockers?
Many medications are in the calcium channel blocker class of drugs. The most common ones are: amlodipine (Norvasc), diltiazem (Cardizem, Cartia, Tiazac), verapamil (Calan, Verelan), felodipine (Plendil), nifedipine (Procardia, Adalat), and isradipine (Dynacirc). There are more calcium channel blockers, but these listed here are the most prescribed ones in the USA.
What conditions do calcium channel blockers treat?
The main conditions treated with calcium channel blockers are: hypertension (high blood pressure), atrial fibrillation (irregular heart rate), cerebral vasospasm (spasms of brain blood vessels), and angina pectoris (chest pain). There are other uses, but these are the primary ones. Moreover, calcium channel blockers are one of the classes of drugs used as the first-line treatment of hypertension.
What are the side effects of calcium channel blockers?
The main side effects are constipation, peripheral edema (swelling of the feet and hands), and gingival overgrowth (increase in the size of the dental gums). Of course, taking too much of a calcium channel blocker may cause the blood pressure to decrease too much, therefore, causing hypotension or dizziness.
The discovery of calcium channel blockers.
The German pharmacologist, Albrecht Fleckenstein, discovered the first calcium channel blocker in 1964: verapamil.
However, an interesting story of the discovery of one of the calcium channel blockers concerns the drug diltiazem. The discovery of this drug occurred in the 1970s and was approved for use in the USA in 1982. The Tanabe Seiyaku Company of Japan wanted to enter the growing market of psychoactive drugs (drugs used for anxiety and depression), and they produced many benzodiazepines (Valium type drugs) with different chemical side chains. During the screening of these compounds, it was found that one of them had a strong coronary vasodilating effect. It was discovered that this drug was a calcium channel
blocker and had a good safety profile. Thus, diltiazem was discovered while searching for an anti-anxiety drug.
Are there any off-label uses of calcium channel blockers?
The main uses in medicine are still the ones treating cardiovascular conditions, however, calcium channel blockers have been used to treat migraine headaches, help with depression, and hyperthyroidism (too much thyroid hormone).
Stay informed and stay healthy.
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