calcium (channel) blocker

n. A family of drugs which work by partially blocking voltage-sensitive calcium channels which are present in electrically excitable cells including muscle, nerve, glial, and blood vessel cells. There are three types of calcium blockers: T types work most in the heart and blood vessels and are used to treat hypertension and arrhythmia; their use results in lower levels of calcium in the walls of blood vessels and in the muscles of the heart, which makes it more difficult for them to be excited and so leads to dilation in blood vessels and lowered output of each heartbeat, both of which lower blood pressure, as well as to a slower and more rhythmic pulse. N type calcium channel blockers have a greater affinity for nerve cells and are used as analgesics, while L type calcium channel blockers are used as antiepileptics.