Evidence suggests that fibromyalgia is related to both chronic sympathetic hyperactivity and decreased levels of serotonin.
To examine the efficacy of pindolol, a mixed serotonin (5-HT)(1A) presynaptic autoreceptor/beta-adrenergic receptor antagonist, in the treatment of fibromyalgia.
An open trial was conducted using 20 female patients who met the American College of Rheumatology criteria for fibromyalgia. Treatment was initiated with pindolol 7.5 mg/day and titrated to a maximum dose of 15 mg/day for a total of 90 days. Primary outcome measures were tender point analysis and the Fibromyalgia Impact Questionnaire (FIQ). Anxiety and depression were measured with the Hamilton Depression and Anxiety Scales and Beck Depression Inventory.
There was significant improvement in primary outcome measures, including Tender Point Count (mean +/- SD, 16.3 +/- 2.2 vs 12.3 +/- 5.0; F = 8.9; p < 0.001), Tender Point Score (24.4 +/- 5.7 vs 17.5 +/- 9.4; F = 7.8; p < 0.001), and FIQ (45.3 +/- 10.8 vs 35.0 +/- 15.0; F = 5.6; p < 0.005). The depression and anxiety scores did not change significantly among women who completed the study, while the impact on cardiovascular parameters was clinically insignificant.
While the current results are encouraging, further studies are needed to determine whether pindolol might be effective in the treatment of fibromyalgia. Limitations of this study include small group size and lack of placebo control.