Reactions 476 - 6 Nov 1993

SCarbamazepine overdose

Congenital disorders: case reportA 44-year-old woman attempted suicide with 24 tablets of

carbamazepine 200mg. She was admitted unconscious, with acarbamazepine serum level of 28.5 µg/ml, 6 hours later, andreceived IV fluids, gastric lavage, and activated charcoal.

The woman was 3–4 weeks post-conception at the time ofingestion of the overdose. This period coincided with theclosure of the fetal neural tube. A 6-fold elevation in maternalserum α-fetoprotein, drawn at 16 weeks estimated gestationalage, was revealed later. Sonographic examination at 20 weeksgestational age revealed a large thoracolumbar spinal defect ofapproximately 17mm length, and the classic ‘lemon sign’ inthe fetal skull, symptomatic of spina bifida.

The patient elected to terminate the pregnancy and wasadmitted for prostaglandin induction 2 days after thesonographic examination. Fetal autopsy revealed a large openmyeloschisis with exposed nerve fibers and vertebral bone inthe thoracolumbar spine region. The left cerebral hemispherewas markedly hypoplastic.

Author comment: It is clinically important to determine theassociation between carbamazepine and spina bifida because90-95% of open neural tube defects can be diagnosedprenatally. Available data suggest that only carbamazepine andvalproate [valproic acid] pose a risk for neural tube defects.Little BB, et al. Megadose carbamazepine during the period of neural tube closure.Obstetrics and Gynecology 82: 705-708, Part 2, Oct 1993 - USA 800230332

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Reactions 6 Nov 1993 No. 4760114-9954/10/0476-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved