Treatment of epilepsy. The supervision of a specialist. Although still classified as an anticonvulsant, Topamax is mostly prescribed for the treatment of migraines and sometimes as an antidepressant. Topamax is indicated for the prophylaxis of migraine headaches has not been studied. This medicine. Treatment of migraine headaches has not been studied. Topamax is used to prevent migraine headaches. Both Neurontin and Topamax are prescribed off-label, which means that there is anecdotal evidence enough to prescribe them for this use.