Clinical Course in Patients with an Intentional Amlodipine Overdose

Jeon, Young Woo; Kim, Jae Yun; Park, Jae Seok; Park, Jae Man; Gil, Hyo Wook; Yang, Jong Oh; Lee, Eun Young; Hong, Sae Yong

Abstract

BACKGROUND/AIMS
Calcium channel blockers (CCBs) are anti-hypertensive medications that are used worldwide. CCB overdose has increased in proportion to the use of these drugs. Although amlodipine is the most widely used CCB, many physicians are not familiar with amlodipine overdose. We report the clinical outcome in patients with an intentional amlodipine overdose.
METHODS
We retrospectively reviewed the medical records of the patients who visited Soonchunhyang University Cheonan Hospital with an amlodipine overdose from January 2002 through December 2010. We recorded the initial vital signs, blood chemistry, electrocardiography, and estimated amount of amlodipine ingested.
RESULTS
Nine patients were enrolled, of whom two patients died. Both patients who died had ingested more than 200 mg/m2 of amlodipine, while all of the patients who ingested less than 200 mg/m2 of amlodipine survived. Three patients had blood sugar levels exceeding 200 mg/dL and two of these died despite high-dose insulin therapy in combination with glucose infusion (hyperinsulinemia/euglycemia therapy). Although three patients also took a glimepiride overdose, none had hypoglycemia. The amount of amlodipine ingested relative to the body surfaced area (BSA) was 197.1 +/- 92.3 mg/m2 in patients with an abnormal ECG and 58.5 +/- 27.1 mg/m2 in patients with a normal ECG.
CONCLUSIONS
Amlodipine overdose can induce hyperglycemia, resulting in lethal cardiogenic shock owing to the decreased calcium influx, inappropriate energy production, and weakened inotropic effect. Therefore, amlodipine-induced hyperglycemia indicates a poor prognosis.