What is Cabergoline?

Cabergoline, marketed under the brand names Dostinex and Cabaser, is a dopamine receptor agonist that is used in the treatment of hyperprolactinemia. It works by blocking dopamine D2 receptors in the pituitary gland to inhibit the secretion of prolactin. It is also a dopamine D1 antagonist and has been used to improve motor coordination in patients with Parkinson's disease. The need to monitor the prolactin level often and have a repeat of MRI pituitary scans every few years ensures cabergoline works well. Patients may even enter remission within a few years and be allowed to stop using this drug.

The onset of action is relatively rapid, and the level of prolactin falls within a few hours after ingestion. This medication should be taken with food to minimize gastrointestinal side effects such as nausea and vomiting. This drug should not be used if you have severe cardiovascular disease, Raynaud's disease, or active gastrointestinal bleeding. It is contraindicated in pregnancy because it can cause a miscarriage.

Some people who have received this drug have problems with gambling or other compulsive urges or behaviors that are difficult to resist. If you experience any of these, report to your doctor right away. Cabergoline may interact with several medications, such as lorcaserin, metoclopramide, prochlorperazine, and certain antifungals including itraconazole, ketoconazole, and posaconazole. It also interacts with certain benzodiazepines, barbiturates, and MAO inhibitors.

Dosage

Cabergoline Tablet is a semisynthetic ergot alkaloid that has a high affinity for dopamine D2 receptors. It acts as a D2-receptor agonist and an antiparkinsonian agent that reduces the motor symptoms of Parkinson's disease by elevating the levels of dopamine in the nigrostriatal pathway. It is orally absorbed and excreted in urine, with an elimination half-life of 68 hours. It is moderately bound to plasma proteins and is a substrate of the CYP3A4 enzyme. Cabergoline coadministered with inhibitors of CYP3A4 can lead to increased serum concentrations of cabergoline.

Cabergoline induced a reduction in the amount of prolactin released from pituitary lactotroph cells and reduced the synthesis of PSG by cultured pituitary cells. It increased the expression of glutamate transporters in cultured cortical neurons and reduced extracellular glutamate accumulation triggered by oxidative stress.

In a small clinical trial, lactating or amenorrheic women within one month postpartum were given either 0.5 mg of cabergoline or placebo. Mammary duct dilation was reduced in more mothers taking cabergoline than in those who took placebo. Serum prolactin levels on day 14 postpartum were measured to confirm the adequacy of this treatment to suppress lactation, and a dose-dependent effect was noted. The adequacy of this therapy was similar to that of bromocriptine. However, more adverse effects occurred in patients taking cabergoline.

Side Effects

Cabergoline is a long-acting dopamine agonist and a prolactin inhibitor. It has higher affinity to D2 receptors, lesser side effects compared with the older drug, bromocriptine. Moreover, it also protects against the death of cultured cortical neurons from oxidative stress through inhibiting the activation of ERK signaling. Additionally, cabergoline also reverses levodopa-induced dyskinesia in patients suffering from Parkinson's disease, besides possessing neuroprotective action due to inhibition of degradation of dopamine.

The drug is rapidly and extensively metabolized in the liver and excreted to a lesser degree in the bile. Absolute bioavailability is unknown. It is well tolerated when administered orally at a low dose, and the doses used in hyperprolactinemia do not cause significant adverse events. However, the prolonged time to reach therapeutic plasma levels can complicate titration regimens and may require careful patient monitoring. The newer agent quinagolide appears to be roughly as effective as cabergoline but is far less studied.

A woman with Cushing's disease was followed throughout her pregnancy and delivered without complications of pregnancy or delivery and had a normal healthy female newborn. Her serum prolactin was below threshold for galactopoiesis at delivery.

A woman with a nonfunctional pituitary adenoma was treated with 1 mg of cabergoline in an effort to reverse lactation. She's breast engagement improved progressively, and her nipple cracking resolved. She was able to nurse her baby. Her serum prolactin returned to normal on day 14 postpartum.

Precautions

The doctor will be very keen to observe you in the initial stages when you are first prescribed Cabergoline. He will most likely order blood tests to determine your prolactin levels before and during the treatment with this drug. Regular MRI scans of your pituitary gland will also be ordered. After 6 months of normal prolactin levels, your endocrinologist will determine whether you can stop taking this medication or if you should continue to take it.

If you have a heart condition, a variety of medication side effects can include arrhythmias or tachycardia, and serious heart conditions may occur with this drug in some individuals. This effect is much more likely to occur if you are over 65 years old, have other medical conditions (liver and/or kidney disease for example), or are taking other drugs that affect the heart rhythm.

Cabergoline may reduce your blood levels of clotting factors, which can make you more susceptible to bleeding or infections. It may also cause an effect on blood pressure, and you may have difficulty standing or sitting up. If this occurs, try to rest as much as possible during the time that you are on this medication.

This medication can interact with other drugs that affect the hormone system in the body, including antipsychotics, lorcaserin, and metoclopramide. It may also affect a couple of blood tests. Inform your doctor and pharmacist about all medications you take, including vitamins and herbs.