Lymphocytic intracellular calcium in a patient with complicated verapamil overdose

Overdose with calcium channel blockers (CCBs) may lead to serious complicat ions. CCBs act by blocking calcium entry into the cell, thus lowering intra cellular calcium ([Ca2+](i)). [Ca2+](i) during CCB overdose has not yet bee n reported. We measured [Ca2+](i) in lymphocytes of a patient with acute ve rapamil overdose with a complex clinical picture. A 59-year-old woman was a dmitted after a suicidal ingestion of 7200 mg of a sustained-release verapa mil preparation. She presented with hypotension, complete atrioventricular block, stupor, hypokalemia, and hyperglycemia. Acute oliguric renal failure , acute pancreatitis, and the adult respiratory distress syndrome further c omplicated her medical course. Treatment was supportive and she recovered c ompletely. Intracellular calcium ([Ca2+](i)) was measured in the patient's lymphocytes using a spectrofluorometer with the calcium-sensitive dye Fura- 2-acetoxymethyl ester. Thirty nine hours after the ingestion, [Ca2+](i) was low at 52 nM (compared with 80 nM in a healthy control subject). Lymphocyt ic [Ca2+](i) did not respond to stimulation with phytohemagglutinin (PHA). Fourteen days after the verapamil overdose, after the patient had recovered completely, lymphocytic [Ca2+](i) was still low at 55 nM. At this time, th ere was an incomplete response to PHA in the lymphocytes. Three months afte r the ingestion, [Ca2+](i) was normal, with a normal response to PHA. Verap amil overdose may run a complex clinical course, but fu II recovery is to b e hoped for with full supportive care. Cellular intoxication, as reflected by low lymphocytic [Ca2+](i), is prolonged and lags behind the clinical rec overy by weeks.