Background/objectives: Animal and human studies suggest that beta(2)-adrenergic agonists exert anabolic effects on muscles, inducing and preventing atrophy after a variety of insults. Based on data from an open-label trial of albuterol in 15 patients with facioscapulohumeral dystrophy (FSHD), the authors conducted a randomized, double-blind, placebo-controlled trial of sustained-release albuterol in this disease.
Methods: Ninety patients were randomized to three groups: placebo; 8.0 mg albuterol twice daily; or 16.0 mg albuterol twice daily. Patients were treated for 1 year with assessments at baseline and weeks 13, 26, and 52. The primary outcome was the 52-week change in global strength by maximum voluntary isometric contraction testing (MVICT). Secondary outcomes included changes at 52 weeks in strength by manual muscle testing (MMT), grip strength, functional testing, and muscle mass assessed by dual energy x-ray absorptiometry (DEXA).
Results: Eighty-four patients completed the study. The mean changes in composite MVICT scores were not significantly different between the groups (mean +/- SD: placebo 0.20 +/- 0.91; low dose -0.04 +/- 0.84; high dose 0.08 +/- 0.98). Similarly, there were no differences in the mean MMT change (placebo 0.04 +/- 0.16; low dose -0.03 +/- 0.13; high dose 0.00 +/- 0.15). Grip improved in both treatment groups compared to placebo (placebo -0.53 +/- 4.13, low dose +1.90 +/- 3.34 [p = 0.02], high dose +1.70 +/- 4.13 [p = 0.03]). The high-dose group had a significant increase in lean mass by DEXA (+1.57 +/- 1.71 kg) compared to placebo (0.25 +/- 2.24; p = 0.007). Albuterol was well tolerated; side effects included cramps, tremors, insomnia, and nervousness.
Conclusions: Although albuterol did not improve global strength or function in patients with FSHD, it did increase muscle mass and improve some measures of strength.