How Bromocriptine Works
Bromocriptine is chemically an ergot alkaloid. The active ingredient binds to binding sites (receptors) of the nerve messenger dopamine and activates them, thereby inhibiting the release of prolactin from the anterior pituitary. The activation of dopamine receptors is also used to treat Parkinson’s disease and acromegaly (increased growth of certain body parts).
Nerve cells in the human brain communicate with each other via messenger substances (neurotransmitters). Such neurotransmitters can be secreted by one cell and perceived by the next via certain receptors on its surface. In this way, a specific signal is transmitted.
Bromocriptine mimics the effect of dopamine in certain areas of the brain when it is deficient. In Parkinson’s disease, such a deficiency occurs because dopamine-forming nerve cells in the midbrain increasingly die off. These cells secrete their messenger substance via long projections into certain regions of the cerebrum, the putamen, a part of the basal ganglia.
The basal ganglia are the brain areas that control the body’s movements. The lack of dopamine therefore causes Parkinson’s patients to experience rigidity and stiffness of movement, generally diminished movements, and trembling of the hands. Bromocriptine, as a dopamine agonist, can alleviate these symptoms.
Absorption, degradation and excretion
Bromocriptine is rapidly absorbed in the intestine after ingestion as a tablet, but only slightly less than half is absorbed. A large part of it is broken down in the liver before reaching the large bloodstream (so-called “first-pass” effect). As a result, only slightly less than five percent of the active ingredient reaches the brain via the bloodstream.
Bromocriptine is broken down by the liver and excreted in the stool. A day and a half after taking the drug, the level of bromocriptine in the body has halved again.
When is bromocriptine used?
The indications for use (indications) of bromocriptine in Germany include:
- Prevention or suppression of natural lactation after childbirth in medically justifiable cases.
- Galactorrhea-amenorrhea syndrome (disturbance of milk production and absence of menstruation)
- Secondary galactorrhea-amenorrhea syndrome caused by medication (e.g. psychotropic drugs)
- Treatment of acromegaly (used alone or combined with surgical treatment or radiotherapy).
In Switzerland, bromocriptine is approved for:
- Acromegaly (used alone or combined with surgical treatment or radiotherapy)
- Hyperprolactinemia in men (such as prolactin-related hypogonadism or prolactinoma)
- Lactation inhibition after childbirth for medical reasons
- Menstrual cycle disorders and infertility (infertility) in women
- Parkinson’s disease (alone or in combination with other Parkinson’s medicines)
Treatment is either short-term over two weeks for weaning or permanent for the treatment of chronic conditions such as Parkinson’s.
There are currently no preparations with the active ingredient bromocriptine on the market in Austria.
How bromocriptine is used
The daily total is divided evenly throughout the day into three to four individual doses, taken with or immediately after a meal with a glass of water.
What are the side effects of bromocriptine?
Side effects in more than one in ten patients include headache, dizziness, fainting, fatigue, depressed mood, and gastrointestinal symptoms (such as nausea, constipation, diarrhea, bloating, cramps, and pain).
Also possible are confusion, agitation, delusions, sleep disturbances, anxiety, movement disorders, visual disturbances, stuffy nose, dry mouth, hair loss, muscle cramps, discomfort during urination, and allergic reactions (swelling, redness, and pain).
In case of occurrence of allergic symptoms after taking Bromocriptine you should notify a doctor.
What should be considered when taking bromocriptine?
Contraindications
Bromocriptine should not be taken in the following cases:
- “pregnancy poisoning” (gestosis)
- uncontrolled high blood pressure
- hypertension during pregnancy or in the puerperium
- evidence of valvular heart disease prior to initiation of long-term treatment with bromocriptine
- for the treatment of non-life-threatening indications, if a severe cardiovascular or mental disease is present at the same time
Drug Interactions
The combination of bromocriptine and other agents may lead to drug interactions:
Bromocriptine is broken down in the liver by certain enzymes (cytochrome P450 3A4) that also metabolize many other drugs. Their degradation can be inhibited if taken at the same time, so that the active substance in question accumulates in the body and can lead to increased severe or even toxic side effects.
Conversely, some drugs are able to attenuate the effect of bromocriptine. These include dopamine antagonists (such as metoclopramide and domperidone) and older antipsychotics (such as haloperidol and chlorprothixene). Treatment with the antifungal drug griseofulvin or the breast cancer drug tamoxifen may completely reverse the effects of bromocriptine.
During therapy you should drink alcohol only with caution, as it is then less well tolerated (so-called alcohol intolerance).
Driving and operating machines
Because of the risk for fainting, you should not drive a motor vehicle or operate heavy machinery during treatment.
Age Limitation
There are insufficient data on the use of bromocriptine in children under seven years of age. Any use in this age group therefore requires a strict medical risk-benefit assessment.
Pregnancy and lactation
Intolerance in the breastfed child when the mother has taken bromocriptine has not been observed to date. During treatment, however, the milk flow dries up. Therefore, breastfeeding women should take bromocriptine only if this effect is desired or if therapy with bromocriptine is unavoidable.
How to get medicines with bromocriptine
Medicines containing bromocriptine are available by prescription in Germany and Switzerland in any dosage and package size.
In Austria, there are currently no preparations with the active ingredient bromocriptine on the market.
Since when is bromocriptine known?
The systematic study of derivatives of ergot alkaloids, which occur naturally in the ergot fungus, led to the development of bromocriptine in the 1950s and 60s. The compound was introduced into clinical use in 1967.
