Carbamazepine toxicity: comparison of measurement of drug levels by HPLC and EMIT and model of carbamazepine kinetics

Extracorporeal life support in a case of acute carbamazepine poisoning with life-threatening refractory myocardial failure

OBJECTIVE

To report the efficacy of extracorporeal life support (ECLS) in acute carbamazepine poisoning with sustained refractory myocardial failure and a high degree of conductance disturbances.

DESIGN AND SETTING

Case report from the toxicological and medical intensive care unit in a university hospital.

PATIENT

A 26-year-old man with severe myocardial failure unresponsive to 1.7 microg kg(-1) min(-1) epinephrine and 1.9 microg kg(-1) min(-1) norepinephrine (SvO2, 17.8% and cardiac index, 0.8 l min(-1) m(-2)) following a suicidal ingestion of 32 g slow-release carbamazepine.

INTERVENTIONS

ECLS (Jostra-Maquet centrifugal pump (Rotaflow) connected to a hollow-fiber membrane oxygenator).

MEASUREMENTS AND RESULTS

ECLS device allowed inotropic drug weaning while maintaining end-organ function and supported the patient until myocardial recovery. The plasma carbamazepine level was 224 micromol/l on admission and peaked at 338 micromol/l 101 h after admission with a prolonged gastrointestinal absorption phase despite multiple doses of activated charcoal. The patient survived and was successfully explanted on day 6. An extensive and regressive thrombosis of the inferior vena cava was noted. Cardiac function totally recovered and at 2-year follow-up. There were no significant sequelae.

CONCLUSIONS

We report a case of life-threatening myocardial failure with conductance disturbances secondary to an acute carbamazepine poisoning, demonstrating the efficacy of ECLS to assist recovery.

Signs and symptoms of carbamazepine overdose in young children

OBJECTIVE

To examine common signs and symptoms of mild to moderate carbamazepine (CBZ) overdose in young children.

METHODS

The medical records of previously healthy children admitted to the pediatric departments for acute accidental CBZ poisoning during the years 1993-1998 were evaluated retrospectively. Information was retrieved on serum CBZ levels, signs and symptoms on admission and during hospitalization, ECG findings, and chemical laboratory test.

RESULTS

There were 14 exposed children all under the age of 5 years. These children accidentally took CBZ prescribed for a family member. The diagnosis of CBZ poisoning in seven children was unknown on admission because of inadequate history and was revealed only on toxicology screen. Nystagmus and drowsiness occurred in 8 of the 14 children, nystagmus and ataxia in 4 children, and drowsiness and tachycardia in another 2 children. The peak CBZ serum levels in these children ranged from 18 microg/ml to 32 microg/ml, mean + SD; 25 microg/ml + 4.64 microg/ml (therapeutic range: 5-10 microg/ml).

CONCLUSION

Based on a certain group of young pediatric patients with mild to moderate CBZ poisoning, it is concluded that, nystagmus is the most common sign of this overdose. Other common signs are drowsiness and ataxia. The presence of nystagmus and CNS depression of unknown etiology, in a young child should suggest the possibility of CBZ toxicity.

Pediatric carbamazepine intoxication

STUDY OBJECTIVE

To describe the clinical effects of carbamazepine ingestion in a pediatric population.

DESIGN

Case series of prospectively evaluated patients and a historical retrospective group.

PARTICIPANTS

All patients younger than 18 years who presented to an urban emergency department with history of carbamazepine ingestion and positive laboratory confirmation.

INTERVENTIONS

Patient demographics, findings on physical examination, serum carbamazepine levels, analysis of 12-lead ECGs, and time and doses of activated charcoal were recorded.

RESULTS

Seventy-seven patients were enrolled, of whom 17 were evaluated prospectively. Serum carbamazepine levels were greater than 12 micrograms/mL (50 mumol/L) in 61 patients. In those 61 patients, mean peak serum level was significantly higher in patients with dystonic reactions (P = .009), coma (P = .002), and apnea (P = .008) than in patients without these symptoms. There was no significant difference in mean peak serum levels between patients with and without seizures. Serum carbamazepine half-life was significantly shorter (P = .022) in patients who received multiple doses of activated charcoal (8.2 +/- 1.6 hours) than in those who received a single dose (12.1 +/- hours).

CONCLUSION

Pediatric patients with suspected carbamazepine ingestion are at higher risk for dystonic reactions, coma, and apnea if the peak serum carbamazepine level exceeds 28 micrograms/mL (117 mumol/L). The development of seizures is not related to peak serum level. Multiple doses of activated charcoal can significantly shorten serum carbamazepine half-life.

Carbamazepine overdose--the effects of multiple dose activated charcoal

We studied five children with carbamazepine overdose. Two patients had acute overdose without previous exposure to carbamazepine while three presented with acute-on-chronic overdose. Multiple doses of activated charcoal were administered to four patients. One acute-on-chronic patient did not receive any activated charcoal. The mean half-life of carbamazepine was as follows: a) Acute vs. Acute-On-Chronic overdose: 8.63 h vs. 12.01 h (p less than 0.05); b) No Activated Charcoal vs. 30-50 g Activated Charcoal vs. 60-90 g Activated Charcoal: 23.3 h vs. 10.17 h vs. 7.21 h (p less than 0.05); c) No Activated Charcoal vs. 2-3 doses vs. 7-12 doses: 23.3 h vs. 8.96 h vs 7.55 h (ns). Although the half-life of carbamazepine decreased in a linear relationship with the total amount of activated charcoal administered (r = -0.86), there was no relationship between the time to complete recovery and administration of multiple doses of activated charcoal. Although multiple doses of activated charcoal increased the clearance of carbamazepine in our patients with overdose, it was not associated with clinical benefits.

Carbamazepine toxicity and poisoning. Incidence, clinical features and management

Carbamazepine is the drug of first choice in the treatment of simple and complex partial seizures and trigeminal and glossopharyngeal neuralgias. It is usually preferred to phenobarbitone or phenytoin because of its powerful antiepileptic activity combined with a relative lack of adverse effects. In this article the mechanisms of action and pharmacological properties of carbamazepine are outlined in order to explain the pathogenesis of most side and toxic effects. Most of these effects, namely those affecting the nervous or cardiovascular systems, correlate well with an increased concentration of the drug in plasma and disappear spontaneously upon discontinuation of therapy. Other, less frequent toxic effects, namely aplastic anaemia or fatal hepatitis, may be ascribed to unforeseeable idiosyncratic reactions. Carbamazepine poisoning, usually accidental and sometimes secondary to the coadministration of other drugs, yields a clinical picture with neurological and cardiovascular signs. The outcome is usually favourable, sometimes with spontaneous improvement, and death is a distinct rarity. No specific antidotes are available. The oral administration of activated charcoal has been shown to be an effective therapeutic measure significantly reducing the plasma half-life of the drug.

A fatal overdose of carbamazepine: case report and review of literature

Carbamazepine is a drug of choice for partial epilepsies, certain affective disorders and neuralgic pain syndromes. It has an excellent safety record; however, overdose can be dangerous. This article reports one of the very few fatalities from carbamazepine overdosage, in an individual with a peak carbamazepine level of 54 mg/L. Manifestations of this and other major carbamazepine overdoses reviewed from the literature were similar to those of tricyclic - anticholinergic overdose, with coma, hypotension, respiratory depression, cardiac arrhythmias, abnormal movements and seizures. Fatality from cardiovascular causes occurred despite decline of serum carbamazepine levels to the putatively non-toxic range, emphasizing the potential for delayed consequences of carbamazepine overdosage. Management should consist of vigorous gastric lavage and installation of activated charcoal, full supportive care in a monitored setting and consideration of early charcoal hemoperfusion, before the patient becomes hypotensive.