Amlodipine Fatality in an Infant with Postmortem Blood Levels

Abstract

Amlodipine is a dihydropyridine calcium channel blocker used in the treatment of hypertension and angina pectoris. Toxic effects reported from amlodipine include hypotension, reflex tachycardia, metabolic acidosis, and pulmonary edema. We report a rare fatality in an infant after ingestion of amlodipine with benazepril, with postmortem blood concentrations. An 11-month-old, 10.88-kg boy ingested 10 to 45 mg amlodipine with 40 to 180 mg benazepril. No action was taken initially because the parents believed only one or two capsules had been ingested. A later count revealed a maximum of nine capsules missing. The child was observed at home and vomited once with possible capsule fragments. Forty-five minutes post-ingestion, the child was noted to be suddenly unresponsive and was brought the local emergency department by a private vehicle. Upon arrival (90 min post-ingestion), the child was unresponsive with the following vital signs HR 133 bpm, BP 67/42 mmHg, respiratory rate 40/min, and temperature 97.5°F. Pertinent abnormal laboratory values were HCO(3) 13 mmol/l and glucose 302 mg/dl. The child was placed on oxygen via a non-rebreather mask and was intubated 45 min post-arrival. The patient became progressively bradycardic, and 55 min after arrival, the patient was in asystole with no palpable blood pressure. Resuscitation measures included chest compressions, epinephrine atropine, sodium bicarbonate, and calcium gluconate. Rescue insulin therapy was begun with 4 units IVP followed by 10 units per hour. Resuscitation efforts persisted for 1 h without success. An autopsy revealed pulmonary edema and no gross or microscopic evidence of natural disease. Stomach contents revealed food matter with small white fragments. Analysis of postmortem heart blood showed amlodipine 1,300 ng/ml (therapeutic <20 ng/ml). Benazepril levels were not available. We believe this is the first reported fatality in an infant from amlodipine. While benazepril may have contributed, ACE inhibitors have not been previously associated with rapid cardiovascular collapse. Small doses of amlodipine (0.9 to 4.1 mg/kg) may produce rapid and fatal cardiovascular collapse in an infant.