Using Gabapentin for Vulvodynia
Abstract & Commentary
By Frank W. Ling, MD
Synopsis: Gabapentin appears to be effective in the treatment of generalized vulvodynia with a low incidence of side effects. Longer-standing cases may be less likely to respond to this therapy.
Source: Harris, G, et al. Evaluation of Gabapentin in the Treatment of Generalized Vulvodynia, Unprovoked. J Reprod Med. 207;52:103.
This retrospective chart review covered all patients with vulvodynia treated with gabapentin at a single facility between January of 2002 and September of 2004. Among 601 charts, 152 fulfilled the criteria of having patients with generalized vulvodynia, being treated with gabapentin as a single agent, having 30 months of follow-up, and having adequate documentation of outcome. Sixty-four percent had at least 80% relief from symptoms. The time needed to achieve this level of therapeutic response varied among the responders. Resolution in less than 6 months occurred in 21% of patients. Seventeen percent responded during the 6-9 month interval and the 9-12 month time period. Seven percent responded during the 12-15 and 15-18 month intervals. Response took longer than 18 months in 29% of patients. Thirty-two percent (N = 49) had no resolution or showed no effect from the medication within 6 months of starting therapy.
The dosing range was from 100 to 3000 mg daily. The most common starting dose was 300 mg in divided doses with titration up to 900 mg daily over 3 weeks. Twenty-eight percent of patients remained at that dose. Thirty-two percent required 1200 mg a day with smaller percentages of response seen at higher doses. Among co-morbidities, sleep disturbance was the only one that negatively impacted drug efficacy. Chronic headache was the most common, occurring in 44% of patients with vulvodynia. Other co-morbidities included: sleep disturbance (43%), irritable bowel syndrome (38%), anxiety (36%), chronic fatigue (23%), and interstitial cystitis (17%). Among the 40 patients with side effects (26%), fatigue was the most common (10%) and was also the most common side effect given as a reason for discontinuation of the medication.
Commentary
I know some of the readers will look down their noses at this study. It's a retrospective chart review so it doesn't pass the scrutiny of scientific rigor. The clinicians in the readership who see these patients in their practices will see some real clinical pearls buried in the article. First of all, the fact that it is a diagnosis of exclusion needs to be reinforced. Oncologic, dermatologic, and infectious etiologies are always in the differential diagnosis and should get first consideration. Another important finding, something that we commonly forget in the busy daily practices that we have, is that the significant incidence of co-morbidities is always muddying up the waters. It becomes more and more challenging to identify a specific gynecologic syndrome among the headaches, bowel issues, and other pain concerns. The third pearl to me is that patience is necessary, on the part of both clinician and patient. Notice that a large proportion of patients got better after many months of treatment. This raises the clinical question of whether the patient got better because of the gabapentin or because it ran through its own course and just resolved. A fourth pearl involves the dosing of the medication, with patients responding to various levels of medication. Once again, the patient and clinician, as a team, should determine together the efficacy of various doses.
As a final note, I find studies like this fascinating. In my own practice, I am loaded down with referrals for patients who turn out to have vestibulitis. Only a small proportion have vulvodynia. One of my additional messages to the reader is to look specifically for vestibulitis with a q-tip. It is extremely easy to overlook. The second add-on message from me is to look beyond gabapentin. The tricyclic antidepressants such as amitriptyline and nortriptyline are commonly used. Remember that other medication such as Lyrica, Gabitril, Keppra and Topamax can also provide some relief for these patients. There isn't very much in the peer-reviewed literature, but there is a lot of clinical experience that we can call on.
This retrospective chart review covered all patients with vulvodynia treated with gabapentin at a single facility between January of 2002 and September of 2004.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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