The efficacy and safety of adjunct bromocriptine therapy for levodopa-induced motor complications: A systematic review

OBJECTIVES: To assess the efficacy and safety of adjunct bromocriptine (BR) compared with placebo in the treatment of patients with Parkinson's disease (PD) who have motor complications. DESIGN: A systematic review of the literature from 1966-1999 on randomized, controlled trials. Outcome measures were occurrence and severity of motor complications, scores on impairment and disability, and the occurrence of side effects. RESULTS: We included eight trials of which the methodologic quality of seven showed important shortcomings. All studies failed to adequately describe randomization procedures and seven studies failed to report sample size calculations. Only one trial was analyzed according to the intention-to-treat principle. It frequently remained unclear if patients with PD actually had motor complications. Differences between studies concerning the baseline characteristics, the BR titration phase, and the applied outcomes were found. The various methods used to evaluate the occurrence and/or severity of motor complications lacked a sound clinimetric basis. A great diversity of impairment and disability scales were applied. For those studies that reported the incidence of side effects, no clear pattern of BR-related side effects emerged. A trend was found for orthostatic hypotension, which more frequently resulted in withdrawal of patients in the BR group. CONCLUSIONS: Major methodologic problems and sources of heterogeneity not only hamper the comparability of trials, but also preclude a conclusion on the efficacy and safety of BR in the adjunct treatment of patients with PD who have motor complications.