Usage
Cabergoline is prescribed for the treatment of hyperprolactinemia (high levels of prolactin in the blood). This condition can lead to irregular or absent menstrual periods in women, infertility, and milk production unrelated to pregnancy (galactorrhea). In men, it can cause decreased libido, erectile dysfunction, and infertility. Cabergoline is also used to treat Parkinson’s disease.
It is pharmacologically classified as a dopamine receptor agonist and belongs to the ergot alkaloid class.
Cabergoline’s mechanism of action involves stimulating dopamine D2 receptors in the pituitary gland, which inhibits the secretion of prolactin.
Alternate Names
While “cabergoline” is the generic name, the drug is marketed under various brand names, most notably Dostinex.
How It Works
Pharmacodynamics: Cabergoline exerts its therapeutic effect by acting as a dopamine D2 receptor agonist. This action specifically targets lactotroph cells within the anterior pituitary gland, leading to a decrease in prolactin synthesis and release.
Pharmacokinetics: Cabergoline is absorbed orally and reaches peak plasma concentrations within 2 to 3 hours. It is highly lipophilic, resulting in extensive distribution throughout the body. It undergoes hepatic metabolism, predominantly via CYP3A4. Elimination is primarily through fecal excretion, with a small portion excreted in urine. Cabergoline has a long half-life, ranging from 63 to 68 hours, allowing for once or twice weekly dosing.
Mode of Action: Cabergoline specifically binds to and activates dopamine D2 receptors on pituitary lactotrophs. Receptor activation inhibits adenylate cyclase activity, reducing intracellular cAMP levels. This cascade ultimately suppresses prolactin gene transcription and protein synthesis.
Receptor Binding, Enzyme Inhibition, or Neurotransmitter Modulation: The primary action is dopamine D2 receptor agonism. While it may have weak interactions with other dopamine receptor subtypes, its clinical effects are predominantly mediated by D2 receptor activation.
Dosage
Standard Dosage
Adults:
For hyperprolactinemia, the initial dose is typically 0.25 mg twice a week, taken with food. The dose can be gradually increased at monthly intervals by 0.25 mg twice weekly, as needed and tolerated, up to a maximum of 1 mg twice a week. For Parkinson’s disease, the usual total daily dose is from 3 to 4.5 mg, taken in divided doses.
Children:
The safety and efficacy of cabergoline have not been established in pediatric patients.
Special Cases:
- Elderly Patients: Start with the lowest dose and titrate cautiously, monitoring for side effects.
- Patients with Renal Impairment: Dose adjustment may be necessary in severe renal impairment.
- Patients with Hepatic Dysfunction: Start with a lower dose and titrate carefully due to the hepatic metabolism of cabergoline.
- Patients with Comorbid Conditions: Careful monitoring and potential dose adjustment may be required in patients with cardiovascular disease or other relevant conditions.
Clinical Use Cases
Cabergoline is not typically used in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU, or emergency situations like status epilepticus or cardiac arrest. Its main indications are hyperprolactinemia and Parkinson’s disease.
Dosage Adjustments
Dose adjustments should be based on the patient’s response to therapy, tolerance of side effects, and other factors such as hepatic and renal function.
Side Effects
Common Side Effects:
Nausea, vomiting, constipation, headache, dizziness, fatigue, dyspepsia, abdominal pain, breast pain.
Rare but Serious Side Effects:
Valvular heart disease (mitral, aortic, or tricuspid regurgitation), pericarditis, pericardial effusion, pleural effusion, pulmonary fibrosis, constrictive pericarditis, psychosis, hallucinations, impulse control disorders (e.g., pathological gambling, increased libido, compulsive shopping).
Long-Term Effects:
The potential for long-term cardiac valvular effects necessitates periodic echocardiographic monitoring, especially with high doses or prolonged use.
Adverse Drug Reactions (ADR):
Any signs or symptoms of valvular heart disease, pericarditis, or pleural effusion should prompt immediate evaluation and potential discontinuation of the drug. Any psychotic symptoms or impulse control issues should be promptly addressed.
Contraindications
Absolute contraindications include hypersensitivity to cabergoline, uncontrolled hypertension, history of pulmonary, pericardial, or retroperitoneal fibrotic disorders, valvular heart disease. Relative contraindications include hepatic impairment and pregnancy with high risk factors for pre-eclampsia or hypertension.
Drug Interactions
Cabergoline can interact with other dopamine agonists, dopamine antagonists (e.g., antipsychotics), antihypertensive medications. Concurrent use of macrolide antibiotics like erythromycin increases the risk of cabergoline toxicity.
Pregnancy and Breastfeeding
Cabergoline is contraindicated during breastfeeding due to its suppression of lactation. Its use in pregnancy is generally avoided, although some data suggest it might be used with caution in specific situations under close monitoring.
Drug Profile Summary
- Mechanism of Action: Dopamine D2 receptor agonist, inhibits prolactin secretion.
- Side Effects: Nausea, vomiting, constipation, dizziness, valvular heart disease (rare but serious).
- Contraindications: Hypersensitivity, uncontrolled hypertension, fibrotic disorders, valvular heart disease.
- Drug Interactions: Dopamine agonists/antagonists, macrolide antibiotics.
- Pregnancy & Breastfeeding: Contraindicated in breastfeeding; generally avoided in pregnancy.
- Dosage: 0.25 mg twice weekly initially for hyperprolactinemia, titrated up to 1 mg twice weekly; higher doses for Parkinson’s disease.
- Monitoring Parameters: Prolactin levels, cardiac function (echocardiography periodically, especially with prolonged use).
Popular Combinations
Cabergoline is not typically used in combination with other medications for its primary indication, hyperprolactinemia.
Precautions
General precautions include monitoring blood pressure, cardiac function, and psychiatric status. Specific populations requiring extra caution include those with hepatic or renal impairment, pregnant or breastfeeding women, and those with a history of cardiovascular disease.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cabergoline?
A: The initial dose is 0.25 mg twice a week, taken with food. This can be gradually increased to a maximum of 1 mg twice a week.
Q2: How does Cabergoline work to lower prolactin levels?
A: It acts as a dopamine D2 receptor agonist in the pituitary gland, inhibiting prolactin secretion.
Q3: What are the most common side effects of Cabergoline?
A: Nausea, vomiting, headache, dizziness, and constipation are common side effects.
Q4: Are there any serious side effects I should be aware of?
A: Yes, although rare, cabergoline can cause valvular heart disease, fibrotic disorders, and impulse control issues. Regular monitoring is essential.
Q5: Can I take Cabergoline if I am pregnant or breastfeeding?
A: Cabergoline is contraindicated in breastfeeding. It is usually avoided during pregnancy unless specifically indicated and managed by a specialist.
Q6: What should I do if I miss a dose of Cabergoline?
A: Take the missed dose as soon as you remember. If it is close to the time of your next dose, skip the missed dose and return to your regular schedule. Do not double the dose.
Q7: How long does it take for Cabergoline to start working?
A: Prolactin levels typically begin to decrease within a few days of starting treatment, although the full effect may take several weeks.
Q8: Does Cabergoline interact with any other medications?
A: Yes, it can interact with other dopamine agonists, dopamine antagonists, and some antihypertensive medications. Inform your doctor about all medications you are taking, including over-the-counter drugs and supplements.
Q9: Can I drink alcohol while taking Cabergoline?
A: Alcohol may exacerbate some side effects like dizziness and nausea. Moderation is advised, and it’s best to discuss alcohol consumption with your doctor.
Q10: Is Cabergoline safe for long-term use?
A: Long-term use requires careful monitoring, particularly for cardiac valvular issues. Regular echocardiograms may be necessary.
