Q. I'm seeking information on Tiagabine used to panic disorder. I have recently started using it as a adjunct to Effexor XR. I can't seem to find any research on this treatment protocol. I am interested in any information (case studies), etc. Can you help?

A. I am not aware of any published studies demonstrating that tiagabine [Gabitril] is either safe or effective in the treatment of panic disorder. Tiagabine is FDA-approved for use in epilepsy; that is, as an add-on agent in the treatment of so-called partial seizures.

Tiagabine acts on a brain chemical called GABA, which normally helps calm down irritable regions of the brain. Basically, tiagabine increases GABA in the brain. Other medications used to treat anxiety and panic disorder also enhance brain GABA--e.g., alprazolam (Xanax), or clonazepam (Klonopin)--and so it is theoretically understandable why someone might try tiagabine for panic disorder (see Ketter et al, Neurology 1999;53(5 Suppl 2):S53-67 for background). However, as I indicated, I am not aware of any controlled studies in this area.

There have been a few studies of tiagabine as an adjunctive agent in bipolar disorder, but even here, the results have been decidedly mixed (e.g., see Kaufman, Annals of Clinical Psychiatry 1998 Dec;10(4):181-4). I think it would be important to seek more information from your doctor regarding the use of Gabitril in panic disorder, as well as to discuss both the risks and benefits of using this agent. (Sorry if I have gotten your role wrong--it's not quite clear from your question whether you are the patient or the clinician!).

July 2002

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