Possible carbamazepine toxicity with terbinafine.
OBJECTIVE
To report a case of carbamazepine and terbinafine interaction resulting in an elevated level of carbamazepine and associated symptoms of toxicity.


METHODS
A 50-year-old Caucasian man developed an elevated carbamazapine level after starting terbinafine, which caused symptoms of toxicity with gait ataxia, dizziness and falls.


CONCLUSIONS
This is a first report of a drug-drug interaction between carbamazapine and terbinafine. Although the mechanism for this interaction is not fully known, it is suspected that terbinafine decreased the metabolism of carbamazapine and led to increased levels that continued even days after the carbamazapine had been stopped. The Naranjo Scale suggests that this was a probable interaction (score 6).


CONCLUSIONS
While several drug-drug interactions have been reported with carbamazapine, there are no previous reports of its interaction with terbinafine. Prescribers should exercise caution when prescribing these medications together.
Baath
Navdeep S
NS
Creighton University Department of Psychiatry, Omaha, NE, USA.
Hong
Jennifer
J
Sattar
S Pirzada
SP
D001714:Bipolar Disorder / Q000097:blood / Q000188:drug therapy; D002220:Carbamazepine / Q000009:adverse effects* / Q000097:blood*; D004347:Drug Interactions; D006801:Humans; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000009:adverse effects* / Q000097:blood*; D000077291:Terbinafine
D009281:Naphthalenes; D002220:Carbamazepine; D000077291:Terbinafine