Effect of propranolol on TMD and fibromyalgia pain: preliminary findings

The underlying biological processes that lead to and maintain spontaneous pain and hyperalgesia in temporomandibular disorders (TMD) and fibromyalgia (FM) are poorly understood. However, data are beginning to accumulate suggesting that enhanced beta-adrenergic drive may be a particular important contributor. Objectives: The aim of this study was to test whether propranolol, a nonselective beta-adrenergic receptor blocker, can reduce clinical pain of patients with TMD and FM. Methods: Two subjects (1 TMD and 1 FM) received 2 weeks of propranolol (10 mg for the first week and 20 mg for the second week) followed by a 2-week wash out period and 2 weeks of placebo tablets. Pain ratings (average pain and percentage of the time that the subjects had pain) and palpation scores (summation of ratings of pain from finger palpation of masticatory muscles) were measured at baseline, at day 4 of 20 mg propranolol, after the wash out period, and at day 11 of the placebo. Subjects were blinded to the type of medication they took at each period. Results: After 7 days of 10 mg and 4 days of 20 mg propranolol, subjects’ rating of average pain decreased by 57%, percentage of the time the waking day that patients had pain decreased 81%, and palpation scores were reduced by 35%. The pain ratings and palpation scores came back to the baseline level after the 2-week wash out period and stay at that level at day 11 of placebo. When participants were asked to indicate which 2-week period they received test medication, both subjects identified correctly that it was the first period. Conclusions: This preliminary finding suggests that propranolol can reduce clinical pain from TMD and FM. However, this is a very preliminary result. Studies with larger population are in progress and will be presented.