High-dose insulin therapy for calcium-channel blocker overdose.
OBJECTIVE
To evaluate the evidence for using high-dose insulin therapy with supplemental dextrose and potassium in calcium-channel blocker (CCB) overdose.


METHODS
Evidence of efficacy for high-dose insulin therapy with supplemental dextrose and potassium was sought by performing a search of MEDLINE and Toxline between 1966 and July 2004 using combinations of the terms calcium-channel blocker, overdose, poisoning, antidote, and insulin. Abstracts from the North American Congress of Clinical Toxicology for the years 1996-2003 were also reviewed.


METHODS
Identified articles, including animal studies, case reports, and case series, were evaluated for this review. No clinical trials were available.


RESULTS
Animal models of CCB overdose demonstrate that high-dose insulin with supplemental dextrose and potassium was a more effective therapy than calcium, glucagon, or catecholamines. High-dose insulin appears to enhance cardiac carbohydrate metabolism and has direct inotropic effects. Published clinical experience is limited to 13 case reports where insulin was used after other therapies were failing; 12 of these patients survived. High-dose insulin therapy was beneficial for CCB-induced hypotension, hyperglycemia, and metabolic acidosis. Bradycardia and heart block resolved in some patients, but persisted in others.


CONCLUSIONS
Based on animal data and limited human experience, as well as the inadequacies of available alternatives for patients with significant poisoning, high-dose insulin therapy warrants further study and judicious use in patients with life-threatening CCB poisoning.
Shepherd
Greene
G
College of Pharmacy, University of Georgia, Augusta, GA, USA. jshepherd@mcg.edu
Klein-Schwartz
Wendy
W
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D002121:Calcium Channel Blockers / Q000506:poisoning*; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D062787:Drug Overdose; D004359:Drug Therapy, Combination; D005947:Glucose / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D007328:Insulin / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D011188:Potassium / Q000627:therapeutic use; D017410:Practice Guidelines as Topic; D016896:Treatment Outcome
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D007328:Insulin; D005947:Glucose; D011188:Potassium