Parlodel contains the active ingredient bromocriptine mesilate, which is a type of medicine called a dopamine agonist. It works by stimulating dopamine receptors in the brain. This can have several results, hence the medicine has several different uses.
Bromocriptine is mainly used to treat disorders that result from high levels of the hormone prolactin in the blood. Prolactin is produced by the pituitary gland in the brain. Bromocriptine decreases the production of prolactin from the pituitary by stimulating dopamine receptors.
A high prolactin level is associated with several conditions. Over-production of this hormone can cause abnormal production of breast milk in both men and women (galactorrhoea), as well as suppression of the sexual glands (hypogonadism), which can result in infertility. High prolactin levels are also associated with some breast and menstrual disorders. Reducing prolactin levels with bromocriptine can therefore improve these conditions.
Bromocriptine is also sometimes used to prevent or stop milk production for medical reasons following childbirth, miscarriage or abortion. Prolactin is the hormone that stimulates the production of breast milk, hence decreasing the production of prolactin with bromocriptine stops milk production.
A further use of bromocriptine is to reduce prolactin production from a type of tumour of the pituitary gland, called a prolactinoma.
Bromocriptine's action on dopamine receptors also decreases the production of growth hormone from the pituitary gland. This is useful for treating conditions where growth hormone is overproduced, such as acromegaly.
Lastly bromocriptine can be used to treat Parkinson's disease. The neurotransmitter dopamine is known to be reduced or absent in the brains of people with Parkinson's disease, and this is thought to be the cause of the disease symptoms. Stimulating dopamine receptors with bromocriptine is similar to replacing the dopamine in the brain, and this reduces some of the symptoms of Parkinson's disease.