Calcium-channel blocking agents for gastrointestinal disorders.

Calcium-channel blocking agents have a potential role in regulation of gastrointestinal tract function by decreasing smooth muscle contraction and possibly inhibiting cellular secretion. Most studies to date have concentrated on the ability of these drugs to inhibit smooth muscle contraction. Verapamil and diltiazem have been shown in animals (opossum, baboon) to produce decreased contractions in esophageal smooth muscle, resulting in a decreased amplitude of peristalsis and decreased lower esophageal sphincter pressures. In studies in man, oral doses of diltiazem and nifedipine have likewise been shown to have similar effects on the esophagus. At present, there is no experimental evidence of a major antisecretory effect of these drugs. In clinical trials, nifedipine has been shown to have a greater effect than placebo in improving symptoms in patients with achalasia, and diltiazem has been suggested as potential therapy in patients with chest pain secondary to excessive esophageal contraction. The precise role for calcium-channel blocking drugs in therapy of gastrointestinal disease is still being explored.