Reactions 766 - 28 Aug 1999

★ SCarbamazepine overdose

Loss of consciousness and first report of hearingloss: case report

Hearing loss occurred in a 34-year-old woman after sheingested 90 carbamazepine 400mg tablets (36g) in a suicideattempt.

On hospitalisation following the overdose, the woman’sGlascow Coma Scale score was 7; her serum carbamazepineconcentration was 177 µmol/L (therapeutic concentration17–50). A nasogastric tube was inserted and she receivedtreatment with activated charcoal until her serumcarbamazepine concentration decreased to 13 µmol/L, by day4. At this time, she started to regain consciousness anddescribed the following symptoms: nausea, headache,dizziness and drowsiness. She had slurred speech andseverely impaired coordination.

The woman reported hearing loss accompanied by a high-pitched tinnitus in both ears 6 days after ingesting theoverdose. An audiogram revealed a 30 to 40dB sensorineuralhearing loss. At follow-up after 2 weeks, she reported asubjective improvement in her hearing, and resolution of thetinnitus and vestibular symptoms. An audiogram revealednormal acoustic thresholds.

Author comment: A functional hearing loss cannot bedefinitely excluded in this patient, but it is unlikely.De La Cruz M, et al. Carbamazepine-induced sensorineural hearing loss. Archivesof Otolaryngology - Head and Neck Surgery 125: 225-227, Feb 1999 -Canada 807166698

» Editorial comment: Auditory disturbance has been reportedpreviously in association with carbamazepine therapy [SeeReactions 728: 6, 21 Nov 1998; 800720374]. However, therehave been no previous case reports of hearing loss associatedwith the agent.

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Reactions 28 Aug 1999 No. 7660114-9954/10/0766-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved