Carbamazepine overdose

eNS depression An 85-year-old woman was taking carbamazepine (200mg bid) for trigeminal neuralgia and calcium fenoprofen for degenerative joint disease. Due to increasing facial pain she increased her intake of carbamazepine and was later found unconscious and admitted to hospital. Serum carbamazepine on admission was 27mg/L. The patient was stuporous, unresponsive to verbal commands but reacted to noxious stimuli. As her condition improved gradually, gastric lavage was not performed and cathartics were not administered. At about 2.30pm the next day, however, she became stuporous once more. Plasma carbamazepine measured 18mg/L. The patient's condition deteriorated further, with no response to pain and development of decerebrate posturing. Plasma carbamazepine was a~sayed again and measured 27mg/ I. On day 4, the patient's condition was SUbstantially unchanged. Plasma carbamazepine was 20mg/L. On day 5 however, the patient's condition began to improve with carbamazepine levels dropping to II mg/L. Subsequent recovery was unremarkable. 11 is likely that large doses of carbamazepine results in overloading of the enzymatic pathways of drug metabolism resulting in an increased elimination half-life of carbamazepine. Delayed increases in serum carbamazepine levels correlating with central depressant effects have been previously described in cases of carbamazepine poisonill8> Rockoff. S. and Basett. R C., Clinical Toxicology 18 935

{NoS. !981>

4 Reactions 11 Jun 1982 0157-7271/82/0611-0004/0$01.00/0 © ADISPress