Carbamazepine

This is an effective medication for trigeminal neuralgia (for which it was originally approved) and partial and generalized seizures. It has the characteristic of possibly worsening absence and myoclonic seizures.

A well-known, dangerous, but rare complication is a drug rash which can progress to Stevens-Johnson Syndrome. In its most fulminant form, it can be fatal. This side effect can occur anytime during its administration. Toxic hepatitis and leukopenia may also occur. Since carbamazepine has other uses, it may be chosen despite its side effects, with the idea that it is treating more than just seizures.

Carbamazepine is also a medication in which levels can be checked. This can be helpful when a patient taking the drug presents with somnolence, dysarthria, and ataxia, and in addition on exam has fine nystagmus and asterixis. This presentation corresponded to a level of 20 (normal 8-12). How the level became this high is unknown.