Side Effects of Dostinex (cabergoline)

Dostinex (cabergoline) is a synthetic ergot derived medication used to treat high levels of prolactin in the blood, a condition known as hyperprolactinemia. 

Dostinex acts on dopamine receptors in the pituitary gland which is located at the base of the brain. Dostinex stimulates D2 (a specific type of dopamine receptor) receptors in the anterior pituitary gland and prevents the production of the hormone prolactin. 

The approval of cabergoline has gradually decreased the use of bromocriptine for the treatment of hyperprolactinemias (abnormally high levels of prolactin in the blood). Dostinex may be more effective than bromocriptine and has less bothersome side effects. Additionally, bromocriptine is given multiple times per day while cabergoline has a longer half-life which allows it to be given twice weekly.

Common side effects of Dostinex include

• nausea,
• headache,
• dizziness or vertigo,
• weakness,
• low blood pressure,
• constipation, and
• stomach pain.

Less common side effects of Dostinex include abnormal heart rhythm changes, pain in the upper middle area of the stomach, nosebleeds, and temporary blindness in one half of the visual field in one or both eyes.

Serious or rare side effects of Dostinex include

• heart problems,
• movement disorders,
• duodenal ulcer,
• facial edema (swelling),
• gastric ulcer,
• hallucinations,
• increased libido,
• pathological gambling,
• psychosis,
• lung problems, and
• weight gain or loss.

Drug interactions of Dostinex include other ergot alkaloids, due to the increased risk for adverse events. Ergot alkaloids are commonly used to treat migraine headaches.

• Patients receiving treatment for migraine headaches should discuss treatment with Dostinex with their doctor or pharmacist before using Dostinex.
• Dostinex works by stimulating dopamine receptors in the brain. It should not be used with dopamine antagonists or blockers which might decrease or cancel out the beneficial effects of Dostinex such as phenothiazines, butyrophenones, thioxanthenes, and metoclopramide. 

No adequate or well-controlled studies have been conducted with Dostinex in pregnant women. Due to the lack of conclusive safety data, Dostinex include should only be used in pregnancy if clearly needed. 

It is unknown if Dostinex include is excreted in human milk. Dostinex should not be used in breastfeeding mothers because it interferes with the production of breast milk.

The safety of Dostinex Tablets has been evaluated in more than 900 patients with hyperprolactinemic disorders. Most adverse events were mild or moderate in severity.

In a 4-week, double-blind, placebo-controlled study, treatment consisted of placebo or cabergoline at fixed doses of 0.125, 0.5, 0.75, or 1.0 mg twice weekly. Doses were halved during the first week. Since a possible dose-related effect was observed for nausea only, the four cabergoline treatment groups have been combined.

The incidence of the most common adverse events during the placebo-controlled study is presented in the following table.

Incidence of Reported Adverse Events During the 4-Week, Double-Blind, Placebo- Controlled Trial

In the 8-week, double-blind period of the comparative trial with bromocriptine, Dostinex (at a dose of 0.5 mg twice weekly) was discontinued because of an adverse event in 4 of 221 patients (2%) while bromocriptine (at a dose of 2.5 mg two times a day) was discontinued in 14 of 231 patients (6%).

The most common reasons for discontinuation from Dostinex were headache, nausea and vomiting (3, 2 and 2 patients respectively); the most common reasons for discontinuation from bromocriptine were nausea, vomiting, headache, and dizziness or vertigo (10, 3, 3, and 3 patients respectively).

The incidence of the most common adverse events during the double-blind portion of the comparative trial with bromocriptine is presented in the following table.

Incidence of Reported Adverse Events During the 8-Week, Double-Blind Period of the Comparative Trial With Bromocriptine

Other adverse events that were reported at an incidence of < 1.0% in the overall clinical studies follow.

• Body As a Whole: facial edema, influenza-like symptoms, malaise
• Cardiovascular System: hypotension, syncope, palpitations
• Digestive System: dry mouth, flatulence, diarrhea, anorexia
• Metabolic and Nutritional System: weight loss, weight gain
• Nervous System: somnolence, nervousness, paresthesia, insomnia, anxiety
• Respiratory System: nasal stuffiness, epistaxis
• Skin and Appendages: acne, pruritus
• Special Senses: abnormal vision
• Urogenital System: dysmenorrhea, increased libido

The safety of cabergoline has been evaluated in approximately 1,200 patients with Parkinson's disease in controlled and uncontrolled studies at dosages of up to 11.5 mg/day which greatly exceeds the maximum recommended dosage of cabergoline for hyperprolactinemic disorders.

In addition to the adverse events that occurred in the patients with hyperprolactinemic disorders, the most common adverse events in patients with Parkinson's disease were

• dyskinesia,
• hallucinations,
• confusion, and
• peripheral edema.

Heart failure, pleural effusion, pulmonary fibrosis, and gastric or duodenal ulcer occurred rarely. One case of constrictive pericarditis has been reported.

Postmarketing Surveillance Data

The following events have been reported in association with Dostinex:

• cardiac valvulopathy and
• extracardiac fibrotic reactions.

Other events have been reported in association with cabergoline:

• hypersexuality,
• increased libido and
• pathological gambling.

In addition, cases of alopecia, aggression and psychotic disorder have been reported in patients taking Dostinex. Some of these reports have been in patients who have had prior adverse reactions to dopamine agonist products.

• Dostinex should not be administered concurrently with D -antagonists, such as phenothiazines, butyrophenones, thioxanthenes, or metoclopramide.