Dopamine Agonist: Cycloset (Bromocriptine)

Bromocriptine is a dopamine D2 receptor agonist approved by the U.S. FDA in 2009 for treatment of type 2 diabetes patients  under the trade name Cycloset. 

How Does Cycloset Work?

Cycloset is a quick-release formulation of bromocriptine. Unlike other medications for type 2 diabetes, Cycloset increases dopamine receptor activity in the morning, which lowers blood sugar—without increasing insulin[1].

Bromocriptine has been in use for decades for treatment of pituitary tumors, Parkinson’s disease (PD), hyperprolactinaemia, and neuroleptic malignant syndrome.

“The idea of using bromocriptine for the treatment of type-2 diabetes came while studying the metabolism of migrating birds; that they develop seasonal insulin resistance and dopamine plays a role in it.” 

Researchers found that Bromocriptine improves glycemic control lowering HbA1c levels by ~0.5%.

Although the exact way bromocriptine works is still unclear, some possible mechanisms by which bromocriptine reduces glucose levels include suppression of endogenous glucose production and/or increased splanchnic glucose uptake after glucose ingestion.

Side effects of Cycloset (Bromocriptine)

The most common adverse side effects associated with bromocriptine are nausea, fatigue, dizziness, vomiting and headache. The drug is also known to be associated with nasal stuffiness, nausea, headache, constrictive pericarditis, neuroleptic malignant syndrome and hypotension.   

The incidence of hypoglycemia was 6.9% among type 2 diabetes patients treated with bromocriptine compared to 5.3% of type 2 diabetes patients receiving placebo.

Because it has a modest glucose lowering effect and frequent abdominal side effects, it is seldomly prescribed in patients with type 2 diabetes. Bromocriptine should not be used by type 1 diabetes patients.

For more information about Cycloset see: http://care.diabetesjournals.org/content/34/4/789.full