Verapamil Overdose: Case Report and Review of the Literature

Abstract

Current controversies regarding the management of verapamil overdose are reviewed. Removal of the drug by gastric lavage is a mainstay of therapy. Administration of syrup of ipecac is contraindicated. Although specific recommendations for calcium dosing in the overdose situation have not been rigorously studied, maintenance of a normal serum ionized calcium concentration is suggested. An exogenous catecholamine, rather than dopamine, may be the drug of choice for treating hypotension. Cardiopulmonary bypass provides a method for drug removal in cases of severe toxicity; however, this invasive method requires further study. Management of fluid/electrolyte, acid/base, and ventilation abnormalities is required to treat large ingestions of verapamil. Treatment guidelines for critical care clinicians are provided.

Prolonged half‐life of verapamil in a case of overdose: implications for therapy.

“…Poisoning with verapamil may be lethal primarily through its cardiovascular effects [9,10]. However, aggressive, pre-emptive treatment often results in recovery, even in very severe cases [11].…”

“…He was ventilated, and haemofiltered because of acidosis and a rising serum creatinine (maximum 424 g1M). His cardiac output was 8.6 1 min -1 (reference range 4-8), pulmonary capillary wedge pressure 21 mm Hg (6)(7)(8)(9)(10)(11)(12), and systemic vascular resistance 456 dyn s-1 m-2 (800-1200). He required dopamine, noradrenaline, and adrenaline to maintain systolic pressure.…”

“…Treatment regimens and outcomes in verapamil overdose have been inconsistent [6,7,[9][10][11][12][13][14][15][16][17]. There is no concentration-survival relation and serum concentrations do not predict outcome [11].…”

“…There is no concentration-survival relation and serum concentrations do not predict outcome [11]. Deaths have occurred with plasma concentrations as low as 600 jg 1-' (therapeutic target range 100-500 jg 1-l) and survival with concentrations as high as 4000 ,ig 1-' [9]. The largest dose associated with survival is 16 g [12].…”

Quantitation of verapamil and norverapamil in postmortem and clinical samples using liquid-liquid extraction, solid phase extraction, and HPLC

“…Several of the reported cases were suicides or attempted suicides [7,11,12]. Fatalities generally occurred within 72 hours after oral administration of verapamil [13].…”