Bromocriptine Mesylate for Glycemic Management in Type 2 Diabetes Mellitus

OBJECTIVE: To review the pharmacologic characteristics, safety, and efficacy of bromocriptine mesylate for glycemic control in patients with type 2 diabetes mellitus. DATA SOURCES: A Scopus and MEDLINE search (1950 June 2010) was conducted using the key words bromocriptine, diabetes, and circadian rhythm. Data were also received from the manufacturer. STUDY SELECTION AND DATA EXTRACTION: Available abstracts, studies, and review articles published in English with human data discussing bromocriptine treatment for type 2 diabetes mellitus were reviewed. DATA SYNTHESIS: Bromocriptine is an ergot derivative available for treatment of type 2 diabetes. The mechanism of action of this agent is unclear; however, activity as a dopamine D-2 receptor agonist seems to provide the primary mechanism for utility in resetting the circadian rhythm in patients with type 2 diabetes. Other mechanisms, including alpha-1 antagonist, (alpha-2 agonist, and serotonin and prolactin modulator, may also help to explain bromocriptine's glucose-lowering effects. Studies with bromocriptine have included 4328 patients with type 2 diabetes. The majority of available trials conducted enrolled patients for a study duration of 6-24 weeks. One trial evaluating the safety and efficacy of bromocriptine concluded after 52 weeks of follow-up. Endpoints of hemoglobin A(1c) (A1C) reduction and plasma glucose concentrations were the primary focus of all studies, with statistically significant differences found. Bromocriptine use resulted in a mean A1C reduction of 0.27% (range 0.1-0.6), while placebo resulted in a mean A1C increase of 0.48% (range 0.3-1.1). Incidence of adverse effects of nausea, vomiting, headache, and rhinitis was greater than that of placebo in clinical trials. Cardiovascular endpoints did not differ from those of placebo. CONCLUSIONS: Bromocriptine has demonstrated efficacy as an adjunctive agent in the management of type 2 diabetes. Caution may be warranted in the elderly population or patients at risk for suspected drug- drug interactions. Further studies of longer duration may help to define the role of bromocriptine in the management of diabetes.