Bromocriptine is used in treatment of diabetes mellitus. It acts by increasing dopaminergic activity in hypothalamus and lowers
HbA1c by 0.6 to 0.9%. It is not to be used in type 1 diabetes and DKA.
Keywords:Bromocriptine; Hypothalamus; Contra indicators; Infarction; Combination therapy; Quick release bromocriptine
Bromocriptine mesylate is a new modality of treatment for
type-2 diabetes. The drug increases dopaminergic activity in
the hypothalamus. It lowers HbA1c by 0.6 to 0.9% compared to
placebo when added to other oral anti-diabetic agents. It regulates
metabolic rhythm. The drug increases insulin sensitivity [1]. There
is 24% increase in insulin mediated glucose disposal. Reduces
fasting and post prandial hyper insulinemia by 30-70%. Body fat
stores and insulin action are controlled by temporal interactions of
circadian neuro-endocrine oscillations. Bromocriptine modulates
neurotransmeter action in the brain and has been shown to
improve glucose tolerance and insulin resistance in obesity and
diabetes. Bromocriptine improves glycemic control and glucose
tolerance in obese type-2 DM. Both fasting and post prandial blood
glucose are reduced. This is due to enhanced maximally stimulated
insulin mediated glucose disposal [2]. No change in body weight or
BMI occurred with this therapy. Mechanism of Action is unclear. It
resets the circadian rhythm at hypothalamic level [3,4]. Preclinical
data suggest that decreased hypothalamic dopaminergic tone may
be involved in the pathogenesis of insulin resistance. The normal
circadian cycle that results in a leaner body in the summer and
heavier body in winter is disrupted in humans because of abundant
caloric intake year-round resulting in the absence of a lean phase.
Stimulation of the hypothalamus promotes the release of several
hormones that respond to the traditional shift in caloric intake
and storage. Quick-release bromocriptine (D2 against), given once
in the morning, stimulates the hypothalamus to release cortisol,
growth hormone, and prolactin, allowing a reset of the circadian
clock permanently stuck in a winter rhythm. This means there
occurs resetting of abnormally elevated hypothalamic drive for
increased plasma glucose, triglyceride and free fatty acid levels in
fasting and postprandial states in insulin-resistant patients. Other
mechanisms, including α-1 antagonist, α-2 agonist, and serotonin
and prolactin modulator, may also help to explain bromocriptine’s
glucose-lowering effects (Table 1). Bromocriptine quick release
(Cycloset) was added on to various antidiabetic agents and studied
for 52 weeks safety trial and was found to be useful as add on
therapy [4].
To be given within 2 hours are waking with food. Starting dose
is 0.8 mg. Recommended dose is 1.6 to 4.8 mg.
Side Effects
Can cause nausea. Taking with food minimise nausea. Can
produce hypotension, somnolence, headache, fatigue, vomiting,
diarrhea, constipation and dizziness. Loss of consciousness during
migraine may reflect dopamine receptor hypersensitivity [5,6].
Contraindications [5,6]
a. Hypersensitivity to Ergot
b. Syncope is potentiated
c. Inhibits lactation, hence, not to be given in lactating
mothers
d. Type-I DM or diabetic ketoacidosis
e. Not to be given during pregnancy
f. Syncopal migraine
Interaction [5,6]
Interact with dopamine receptor antagonist, clozapine,
olanzapine and reduces the effectiveness. Increases serum levels of
Salycilates, Sulfonamide, Chloramphenicol and Probenecid due to
its high protein binding character. Avoid using concomitantly with
other Dopamine antagonist such as neuroleptics. They diminish the
effectiveness of Bromocriptine.
Storage
Store at 25°C and protect from light and moisture.
Bromocriptine mesylate is indicated as an adjunct to diet and
exercise to improve glycemic control in adults with type-2 diabetes
mellitus. It may be used as monotherapy or as adjunctive therapy
to metformin/sulfonylurea. It should not be used to treat type-1
diabetes or diabetic ketoacidosis.
Gaziano JM (2007) Quick-release bromocriptine has favorable cardiovascular safety profile. Proceedings of the 67th Annual Scientific Sessions of the American Diabetes Association, USA.
Bromocriptine mesylate approved for treatment of type 2 diabetes (2009) Endocrine today.