Clinical experience with diltiazem in Japan.

In a cooperative postmarketing study, 3,913 Japanese patients received diltiazem, an orally administered calcium channel blocking agent, for 30 to over 360 days. Drug safety was assessed by monthly evaluations of subjective symptoms, electrocardiographic recordings, adverse experiences, vital signs, and biochemical profiles. Original case report forms were processed and analyzed in the United States. None of the observed adverse experiences were serious or life threatening. They occurred in 1.8% of the patients and primarily involved the gastrointestinal system; anorexia and nausea were the most common adverse effects. The majority of the other adverse experiences were extensions of the drug's pharmacologic effects. Diltiazem appears to cause relatively minor clinical toxicity at a low frequency.