Gabapentin is a relatively new anticonvulsant indicated for adjunctive ther
apy in the treatment of partial seizures, with and without secondary genera
lization, in adults with epilepsy. Overall, it has a minimal side effect pr
ofile compared with other anticonvulsant agents. Postmarketing surveillance
is needed to further delineate the spectrum of adverse events that may be
experienced by patients treated with this medication. This is a case report
of a 25-year-old man with a 10-year history of mood swings that progressiv
ely worsened and resulted in a suicide attempt 8 months before his first ap
pointment. A diagnosis of bipolar disorder was established, and a clinical
interview ruled out other mental disorders. The patient was administered ga
bapentin 300 mg/day, and the dose was titrated upward to 900 mg/day, A foll
ow-up appointment revealed improved control of his bipolar symptoms. Howeve
r, the patient reported that he could not have an orgasm during sexual inte
rcourse. The medication was changed to valproic acid 250 mg three times dai
ly. His bipolar symptoms remained under control and the anorgasmia resolved
, This was maintained at the next follow-up appointment. The side effect pr
ofile and therapeutic monitoring requirements of gabapentin are favorable w
hen compared with those of other anticonvulsant agents. However, because th
is agent is relatively new, especially for use in the treatment of bipolar
disorder, a more thorough development of its side effect profile is needed.
Observing, recording, and reporting atypical adverse events and side effec
ts are critical to postmarketing surveillance and enhance the clinician's a
bility to make rational therapeutic decisions.