Delayed elimination half-life of amlodipine in a case of drug overdose.

A 75 year-old-female was transferred to our ICU by an ambulance for refractory hypotension. The patient was suspected to have acute amlodipine (AML) overdose based on the information obtained from patient's family. Serum AML concentration was 355.6 ng/mL on the 1st hospital day. The patient's blood pressure was gradually elevated by intravenous administration of noradrenaline, calcium chlo- ride and insulin, and the patient was transferred to another hospital on the 9th hospital day. The analysis of serum AML concentration showed delayed elimination half life in the early period after the inges- tion. It was thought that decrease in the hepatic clearance of AML by the saturation of metabolism could contribute to the delayed elimination. Severe AML overdose may cause prolonged elimination half-life.