A good night’s sleep eludes many people with epilepsy, thus significantly impacting their quality of life. And while there has been speculation regarding the role specific antiepileptic drugs (AEDs) may have on sleep quality in people with epilepsy, there have been few studies examining the relationship with insomnia—until now. Today, Carl Bazil, M.D., Associate Professor of Clinical Neurology, Columbia University, and colleagues presented their latest research exploring the link between AEDs and insomnia at the American Epilepsy Society 59th Annual Meeting in Washington DC.

Bazil’s interest in investigating the effect specific AEDs have on sleep in patients with epilepsy began with clinical observations that some patients improved in terms of sleep with certain agents, while others developed insomnia. “There have been studies for years suggesting that certain AEDs could adversely affect sleep, especially phenobarbital and phenytoin. There are others (like felbamate) that were shown to commonly cause insomnia starting in the initial clinical trials. So I became interested in further exploring these relationships”, said Bazil.

Bazil et al. used the Columbia University AED database, which includes detailed information on patients taking virtually all marketed AEDs, alone or in combination. Data were compiled on all outpatients seen from January 1, 2000 to January 1, 2004. The researchers correlated insomnia, as reported by patients or physicians during routine office, with the use of individual AEDs, and evaluated insomnia resulting in AED dose reduction or discontinuation. They also looked at predictors of insomnia independent of AED use, including: gender; epilepsy classification; presence of cognitive, psychiatric, or sedative side effects; and history of epilepsy surgery.

Results

Medical records from 818 patients were included in the study. All patients had been newly started on one of the 14 AEDs, either as monotherapy or in combination with other AEDs. Insomnia was seen most commonly with felbamate (18%) especially when compared with all other drugs. The data also revealed that insomnia was seen with lamotrigine and zonisamide (3%), topiramate (2%), and levetiracetam and gabapentin (1%), though at much lower frequencies. Drugs not associated with insomnia included: clobazam, carbamazepine, oxcarbazepine, phenobarbital, phenytoin, tiagabine, vigabatrin, and valproate.

“We found that insomnia is significantly associated with felbamate use and is seen rarely with several other AEDs, particularly lamotrigine, zonisamide, and levetiracetam. For other AEDs, particularly those with known sedative effects, we did not see insomnia. That insomnia was most commonly reported with felbamate was not surprising, but confirms anecdotal reports”, said Bazil.

Bazil recognizes the need for further research regarding insomnia in the epilepsy population. He believes future research needs to be focused specifically on the examination of sleep problems, sleep disorders, and sleep habits as well as seizures and AED use. “We are actually in the process of conducting a study looking at a large outpatient population for determination of the prevalence of various sleep disorders, including insomnia. This will be a first step in research ultimately looking at the impact of insomnia and other sleep disorders not only on the occurrence of seizures in these patients, but also on their overall quality of life. We think that for many patients, stopping seizures may not be enough if other disorders such as insomnia remain.”

The abstract of this study is published in Epilepsia 2005, Vol. 46, Supplement 8, p.169.