Bromocriptine Mesylate

Brands

Parlodel, Alti-Bromocriptine (Canada), Apo-Bromocriptine (Canada), Parlode (Canada)

Availability

Snap Tab: 2.5 mg
Capsules: 5 mg

Pharmacology

Bromocriptine mesylate, a semisynthetic ergot alkaloid, is a dopamine receptor agonist that inhibits the release of prolactin from the anterior pituitary, which in turn reduces circulating serum prolactin and interferes with lactation.

In the tuberoinfundibular process dopaminergic neurons influence the secretion of prolactin from the anterior pituitary by secreting dopamine, an inhibitor of prolactin. In the corpus striatum dopaminergic neurons help to control motor function.

Studies have shown that bromocriptine induces long lasting stereotyped behavior in rodents and turning behavior in rats having unilateral lesions in the substantia nigra (a structure located in the midbrain that produces dopamine and that plays a part in motor control). Actions such as these, characteristically produced by dopamine, are inhibited by dopamine antagonists and point towards a direct action of bromocriptine on striatal dopamine receptors.

Bromocriptine mesylate is both a nonhormonal, nonestrogenic, agent that inhibits the secretion of prolactin with little to no effect on other pituitary hormones. However, because the drug does inhibit lactation it is not recommended that it be given to a female rat that is or will be nursing a litter.

Bromocriptine mesylate is metabolized in the gastrointestinal tract and liver. More than 90% of the absorbed dose undergoes first-pass metabolism.
The major route of excretion of bromocriptine is primarily in bile. Nearly all the dose is excreted in feces with only about 2-6% of the oral dose excreted via the urine. The elimination half-life of bromocriptine is approximately 6 hours.

Although bromocriptine is similar to cabergoline, the drug has less selectivity for dopamine D2 receptors, and with a shorter half- life requires a more frequent dosing regimen than cabergoline. Side effects are also reportedly less with cabergoline than with bromocriptine. Expense, dosing frequency and compliance, availability, and side effects may play a factor in choosing whether bromocriptine or cabergoline is more suitable when treating the pet rat.

Indications

May be beneficial in reducing the size of prolactin-secreting pituitary adenomas, in rats.

Or, where there has been removal of existing benign (adenoma) mammary tumors the use of a prolactin secretion inhibitor such as bromocriptine may be beneficial in the prevention of new benign tumor growth.

Drug Interactions or Contraindications

Avoid administering bromocriptine concurrently with D2-antagonists, such as phenothiazines, butyrophenones, thioxanthenes, or metoclopramide since efficacy could be reduced.
Plasma levels of bromocriptine may increase when co-administered with erythromycin or ketoconazole.

Adverse Reactions

CNS: stroke, seizures, lethargy

CV: low blood pressure, abnormal/irregular heart beat, valvulopathy, pericardial fibrosis

Resp: nasal congestion, pleural/pulmonary fibrosis

GI: nausea ( in rats this seen by inappetence and pica), decreased appetite, dry mouth, diarrhea, constipation

GU: urine retention

Hepatic: liver impairment

Skin: pruitus (itching), coolness & pallor of feet and tail.

Other: behavioral changes, inhibits lactation

*Note: overdosing can result in acute toxicity. The side effects of bromocriptine are primarily dose related. Decreasing the dosage may help to reduce those side effects.

Dosage Recommendations

*Note: if impaired liver function is thought to be present the reduction of dosage may need to be considered.

3 mg/kg per day ³⁶

Considerations

Give with food to minimize gastric distress.
Keep capsules and tablets in closed container. Store at room temperature away from light.
Suspensions made from capsules or tablets should be refrigerated.

Consultant

Thomas M. Donnelly, DVM, DACLAM, Warren Institute | 712 Kitchawan Rd, Ossining NY 10562-1118 USA

Reference

Onaolapo, O., & Onaolapo, A. (2013). Subchronic oral bromocriptine methanesulfonate enhances open field novelty-induced behavior and spatial memory in male Swiss albino mice. Neuroscience Journal, 2013(948241). Retrieved June 19, 2013, from https://www.hindawi.com/journals/neuroscience/2013/948241/
Santa Cruz Biotechnology, Inc. (2010, April 21). Bromocriptine mesylate [Material Safety Data Sheet]. Retrieved from http://datasheets.scbt.com/sc-200395.pdf
Al-Khalisi, M., & Al-Khateeb, H. (2005). Testing bromocriptine dose necessary for suppression of lactation in rats: morphological study . Sci. J . Nursing/ Baghdad, 18(2), 48-51. Retrieved June 19, 2013, from https://www.iasj.net/iasj?func=fulltext&aId=37805
Cycloset (bromocriptine mesylate) tablets. (2010, September). Type 2 Diabetes Treatment – CYCLOSET (bromocriptine mesylate tablets). Retrieved June 19, 2013, from https://www.cycloset.com/assets/pdf/cycloset-pi-final.pdf
Bromocriptine mesylate capsule [Sandoz Inc]. (2010, April). DailyMed. Retrieved June 19, 2013, from http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=deeea4f0-389e-4b2f-b0a7-60a87feac62a
Mayer, J., Sato, A., Kiupel, M., DeCubellis, J., & Donnelly, T. (2011). Extralabel use of cabergoline in the treatment of a pituitary adenoma in a rat. J Am Vet Med Assoc., 239(5), 656-60.
Dall’Ara, A., Lima, L., Cocchi, D., Salle, E. D., Cancio, E., Devesa, J., Müller, E. (1988). Inhibitory effect of cabergoline on the development of estrogen-induced prolactin-secreting adenomas of the pituitary. Eur J Pharmacol., 151(1), 97-102.
http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=deeea4f0-389e-4b2f-b0a7-60a87feac62a