Dibor R Mechanism of Action

Pharmacotherapeutic Group: Type 2 anti-diabetic drug.
Pharmacology: Pharmacodynamics: Mechanism of Action: Dibor R contains bromocriptine mesilate, an ergot derivative that is a dopamine receptor agonist. The mechanism by which bromocriptine improves glycemic control is unknown. Monitoring administration of bromocriptine improves glycemic control in patients with type 2 diabetes without increasing plasma insulin concentrations.
Once daily morning administration of bromocriptine to humans increases circulating levels of bromocriptine, a dopamine receptor agonist, for 4-5 hrs after administration.
Pharmacokinetics: Absorption: When administered orally, approximately 65-95% of the bromocriptine dose of bromocriptine mesilate is absorbed. Due to extensive hepatic extraction and first-pass metabolism, approximately 7% of the dose reaches the systemic circulation. Under fasting conditions the time to maximum plasma concentration is 53 min. In contrast, following a standard high-fat meal, the time to maximum plasma concentration is increased to approximately 90-120 min. Also, the relative bioavailability of bromocriptine is increased under fed as compared to fasting conditions by an average of approximately 55-65% (increase in AUC_inf).
Distribution: Bromocriptine is 90-96% bound to plasma proteins. The volume of distribution is approximately 61 L.
Metabolism: Bromocriptine mesilate is extensively metabolized in the gastrointestinal tract and liver. Metabolism by CYP3A4 is the major metabolic pathway. Most of the absorbed dose (approximately 93%) undergoes the first-pass metabolism. The remaining 7% reaches the systemic circulation.
Elimination: The major route of bromocriptine is in the bile with the remaining approximately 2-6% of an oral dose excreted via the urine. The elimination half-life (t_½) is approximately 6 hrs. Prior consumption of a standard high-fat meal has little to an effect on the elimination t_½ of bromocriptine.