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[×] COMT inhibitors
 BRAND NAMES
 MECHANISM OF ACTION
Cabergoline, an ergot derivative, is a potent dopamine receptor agonist on D2 receptors. It acts by direct stimulation of the D2-dopamine receptors on pituitary lactotrophs, thus inhibiting prolactin secretion. Cabergoline has a longer lasting prolactin lowering activity than bromocriptine. The prolactin lowering effect is dose-related.
- Suppression of physiological lactation
- Treatment of dysfunctions associated with hyperprolactinemia, including amenorrhea (absence of menstruation), oligomenorrhea (infrequent menstruation), anovulation and galactorrhea (inappropriate production of milk). Hyperprolactinaemia is an endocrine disorder seen in men and women, which is associated with impaired gonadal function. The most common symptoms in women are secondary amenorrhea, reduced libido, menstrual disorders, and galactorrhea. In men, symptoms generally include reduced libido and/or impotence.
- Patients with prolactin-secreting pituitary adenomas (micro and macroprolactinomas)
- Idiopathic hyperprolactinemia
- Monotherapy of Parkinson's disease in the early phase
- Combination therapy, together with Levodopa/Carbidopa (Sinemet), in progressive-phase Parkinson’s disease.
- Inhibition of lactation: The recommended therapeutic dosage is 1 mg (two 0.5 mg tablets) given as a single dose, during the first day post-partum.
- Suppression of established lactation: The recommended therapeutic dosage regimen is 0.25 mg (one half 0.5 mg tablet) every 12 hours for two days.
- Treatment of hyperprolactinemic disorders: The recommended initial dosage of Cabergoline is 0.5 mg per week given in one or two (onehalf of one 0.5 mg tablet) doses (e.g. on Monday and Thursday) per week. The weekly dose should be increased gradually, preferably by adding 0.5 mg per week at monthly intervals until an optimal therapeutic response is achieved. The therapeutic dosage is usually 1 mg per week and ranges from 0.25 mg to 2 mg per week.
Doses of Cabergoline up to 4.5 mg per week have been used in hyperprolactinemic patients.
The weekly dose may be given as a single administration or divided into two or more doses per week according to patient tolerability. Division of the weekly dose into multiple administrations is advised when doses higher than 1 mg per week are to be given since the tolerability of doses greater than 1 mg taken as a single weekly dose has been evaluated only in a few patients.
Patients should be evaluated during dose escalation to determine the lowest dose that produces the therapeutic response. Monitoring of serum prolactin levels at monthly intervals is advised since, once the effective therapeutic dosage regimen has been reached, serum prolactin normalization is usually observed within two to four weeks.
After Cabergoline withdrawal, recurrence of hyperprolactinemia is usually observed. However, persistent suppression of prolactin levels has been observed for several months in some patients. In most women, ovulatory cycles persist for at least 6 months after Cabergoline discontinuation.
- Hypersensitivity to cabergoline, any other component of the product, or any ergot alkaloid.
- Uncontrolled hypertension
- Heart valve problems: Cabergoline is contraindicated in patients with anatomical evidence of cardiac valvular disorders (eg, echocardiogram showing valve leaflet thickening, valve restriction, valve mixed restriction-stenosis). Echocardiogram is required at pretreatment in patients being treated for hyperprolactinemic disorders to assess the potential presence of asymptomatic valvular disease.
- A history of lung or heart problems related to fibrotic tissues (tissues are hardened due to scarring.)
 WARNINGS AND PRECAUTIONS
- Cabergoline may cause hypotension. Care should be exercised when administering Cabergoline concomitantly with other drugs known to lower blood pressure (initial doses >1 mg may cause orthostatic hypotension)
- Hepatic impairment: Lower doses should be considered in patients with severe hepatic insufficiency who receive prolonged treatment with Cabergoline
- Cabergoline should be given with caution to subjects with severe cardiovascular disease, Raynaud’s syndrome, peptic ulcer or gastrointestinal bleeding, or with a history of serious, particularly psychotic, mental disorders. Particular care should be taken when patients are taking concomitant psychoactive medication.
- Cabergoline has been associated with somnolence. When initiating therapy, the patient should not drive or engage in activities in which alertness is required.
- During treatment of Hyperprolactinemia: Fibrotic disorders can have an insidious onset and patients should be regularly monitored for possible manifestations of progressive fibrosis. Therefore, during treatment, attention should be paid to the signs and symptoms of:
- Pleuro-pulmonary disease such as dyspnoea, shortness of breath, persistent cough or chest pain
- Renal insufficiency or ureteral/abdominal vascular obstruction that may occur with pain in the loin/flank and lower limb oedema as well as any possible abdominal masses or tenderness that may indicate retroperitoneal fibrosis.
- Cardiac failure: cases of valvular and pericardial fibrosis have often manifested as cardiac failure. Therefore, valvular fibrosis (and constrictive pericarditis) should be excluded if such symptoms occur.
Additional appropriate investigations such as erythrocyte sedimentation rate, and serum creatinine measurements should be performed if necessary to support a diagnosis of a fibrotic disorder.
- Medicines contain ergot alkaloids (e.g., to treat migraine headache): Although there is no conclusive evidence of an interaction between Cabergoline and other ergot alkaloids, the concomitant use of these medications during long-term treatment with Cabergoline is not recommended.
- Macrolide antibiotic (e.g., erythromycin, clarithromycin): Cabergoline should not be used in association with macrolide antibiotics since systemic bioavailability and also adverse effects could increase.
- Dopamine antagonists such as medicines to treat mental illness and prevent nausea (e.g., phenothiazines, butyrophenones, metoclopramide): Since Cabergoline exerts its therapeutic effect by direct stimulation of dopamine receptors, it should not be concurrently administered with drugs that have dopamine-antagonist activity since these might reduce the prolactin-lowering effect of Cabergoline.
- Food is not noted to affect the absorption of Cabergoline
 PREGNANCY AND LACTATION
- Pregnancy Category B (US).
- Nursing mothers: Cabergoline should not be given to women postpartum who are planning to breastfeed.
 SIDE EFFECTS
The most common adverse events are nausea, abdominal pain, headache and dizziness.
Less commonly reported side effects are palpitations, pain in the upper middle of the abdomen, somnolence, nose bleeding, and temporary blindness in one half of the visual field of one or both eyes.
For serious adverse reactions (See WARNINGS AND PRECAUTIONS)