Tiagabine (Gabatril)

Quite a number of authors have mentioned tiagabine as a treatment for bipolar disorder.  There have been at least three favorable open trial reports vs. one unfavorable.  I have seen a report that many psychiatrists have prescribed tiagabine to one or more of their tiagabine patients.  But as of the present, I have yet to see a since double-blind study using tiagabine for anything other than partial epilepsy for which it is FDA approved. 

In my opinion, it is simply wrong to prescribe tiagabine for bipolar disorder until there is at least one and preferably two double-blind studies showing benefit.  This is especially true since two other anti-convulsants, gabapentin and topiramate, also had numerous open trials claiming they were beneficial for bipolar disorder only to have failed in four out of four double-blind studies.  Tiagabine causes many side-effects, some of them serious.

Of the four open trial reports, one is very negative and another is not very flattering.  However, three of them are very poorly worded reports that should never have been published.  Tiagabine is not a promising medication.

Psychotic symptoms (hallucinations) were observed in three (0.8%) of 356 TGB-treated patients and none of 198 placebo-treated patients (p = 0.556, NS). Epilepsia. 2002 Apr;43(4):394-8.

Might Be Equal to an SSRI for Anxiety: A randomized but open 10-week trial of tiagabine 4-16 mg/d vs. paroxetine 20-60 mg/d for 40 patients with anxiety disorders found both groups improved equally. Tiagabine is a GABA reuptake inhibitor, thereby increasing GABA effect in the nervous system. San Diego. Tiagabine for the treatment of generalized anxiety disorder: a randomized, open-label, clinical trial with paroxetine as a positive control. Rosenthal M. J Clin Psychiatry. 2003 Oct;64(10):1245-9. Ed: Why anyone would want to use the expensive and poorly researched tiagabine for anxiety when so many less expensive and better researched alternatives are available is beyond me. This study had no placebo group so it is impossible to tell how much either medicine helped, if at all. The author claims that the medicines reduced anxiety and depression, but he has no proof for this because the simple progression of time may have done it.  Indeed, paroxetine is a poor choice for an SSRI due to its short duration of action.

Tiagabine Little Value in Bipolar Depressed. Thirteen patients received a mean of 38 days of treatment at a mean dose of 8.7 mg/day of tiagabine. On the Clinical Global Impression Scale for Bipolar Disorder Overall category, three (23%) patients showed much or very much improvement and 10 (77%) patients showed no change or worsening. Three significant adverse events were noted, including two presumptive seizures. Bipolar Disorders: Volume 4 Issue 5 Page 283 - October 2002