Amlodipine overdose

Abstract

Objective: To report a nonfatal intentional overdose of amlodipine.

Case summary: A 42-year-old woman with a history of hypertension reported ingesting 50-100 mg amlodipine besylate and at least 40 ounces of beer in a suicide attempt. The patient's symptoms were mild; BP ranged from 79/50 to 113/76 mm Hg and HR from 92 to 129 beats/min (sinus tachycardia). Laboratory studies revealed normoglycemia, mild metabolic acidosis, mild hypocalcemia, blood ethanol concentration of 263 mmol/L, and a serum amlodipine concentration of 88 ng/mL (normal 3-11) 2.5 hours after ingestion. Therapy included activated charcoal, whole bowel irrigation, and intravenous NaCl 0.9%. After receiving 1.5 L of NaCl 0.9%, the patient developed signs of mild pulmonary edema that resolved over several hours without intervention. A serum amlodipine concentration obtained 35 hours later was 79 mg/mL. The patient was discharged on day 2 in good condition.

Discussion: In this case, an amlodipine overdose was associated with sustained hypotension and sinus tachycardia, as well as transient pulmonary edema following relatively low-volume fluid replacement. A previously published report described an amlodipine overdose that was fatal due to refractory hypotension and was complicated by concomitant oxazepam overdose.

Conclusions: Amlodipine overdose produces prolonged hemodynamic effects and may lead to pulmonary edema. Due to a long elimination half-life and delayed onset of effects, patients with amlodipine overdose should receive aggressive decontamination therapy and may require extended clinical monitoring and supportive care if they are hemodynamically unstable.