Limited efficacy of gastrointestinal decontamination in severe slow-release carbamazepine overdose.
OBJECTIVE
To report the limited efficacy of both multiple doses of activated charcoal (MDAC) and whole bowel irrigation (WBI) in a patient with severe overdose of slow-release carbamazepine.


METHODS
A 25-year-old man was admitted in a comatose state with seizures after a suicide attempt with slow-release carbamazepine. Serum carbamazepine concentration on admission (16 h postingestion) was 52.08 microg/mL. The patient was mechanically ventilated and treated with MDAC and a 4 hour charcoal hemoperfusion. Carbamazepine concentration at the end of hemoperfusion was 27.16 microg/mL. Despite continuous treatment with MDAC, a rebound in carbamazepine concentration to 36 microg/mL was observed 32 hours after hemoperfusion (58 h postingestion). WBI was performed over a 10 hour period. The carbamazepine concentration continued to increase to 38.55 microg/mL and seizures recurred. After WBI was performed, MDAC was reinstituted; 33 hours later (102 h postingestion), the carbamazepine concentration began to decline. The hospitalization course was complicated by pneumonia, which necessitated continuation of mechanical ventilation and administration of antibiotics. The patient recovered completely and was discharged without sequelae 15 days after admission.


CONCLUSIONS
Serum carbamazepine concentration and toxicity were effectively reduced by hemoperfusion. The role of MDAC coadministered during hemoperfusion cannot be ruled out. However, a rebound in carbamazepine concentration with recurrent seizures was observed despite MDAC and WBI. The most likely explanation for this rebound (65 h postingestion, 39 h posthemoperfusion) is prolonged absorption, possibly from a pharmacobezoar. Redistribution cannot be excluded, but this is not supported by the concentration-time course and previous reports.


CONCLUSIONS
Both MDAC and WBI may be ineffective in reducing absorption and enhancing elimination in overdose of slow-release carbamazepine. Repeated hemoperfusion or other elimination enhancement techniques should be considered when the clinical and toxicokinetic course suggests the presence of a refractory pharmacobezoar.
Israel Poison Information Center, Rambam Health Care Campus, The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel. y_lurie@rambam.health.gov.il
Yael
Y
Lurie
Yedidia
Y
Bentur
Yishai
Y
Levy
Elena
E
Baum
Norberto
N
Krivoy
D000328:Adult; D000931:Antidotes / Q000627:therapeutic use; D018692:Antimanic Agents / Q000506:poisoning; D002220:Carbamazepine / Q000506:poisoning*; D002606:Charcoal / Q000627:therapeutic use*; D003666:Decontamination; D062787:Drug Overdose; D006801:Humans; D041741:Lower Gastrointestinal Tract; D008297:Male; D010554:Personality Disorders / Q000188:drug therapy; D013406:Suicide, Attempted; D007507:Therapeutic Irrigation
D000931:Antidotes; D018692:Antimanic Agents; D002606:Charcoal; D002220:Carbamazepine