Usage
- Piribedil is prescribed for the treatment of Parkinson’s disease, both as monotherapy and as adjunct therapy with levodopa. It is particularly beneficial in cases with prominent tremor. It is also used to treat cognitive impairment in the elderly, dizziness, and intermittent claudication due to peripheral arterial occlusive disease (stage II).
- Pharmacological Classification: Dopamine agonist, α₂-adrenergic antagonist.
- Mechanism of Action: Piribedil acts primarily as a dopamine agonist, stimulating D₂ and D₃ receptors in the brain. This action helps to compensate for dopamine deficiency, a key factor in Parkinson’s disease. Its α₂-adrenergic antagonist properties may contribute to improved cerebral blood flow and cognitive function.
Alternate Names
- Pronoran, Trivastal, Trastal, Trivastal LP, Trivastan ritardo.
How It Works
- Pharmacodynamics: Piribedil primarily stimulates D₂ and D₃ dopamine receptors, improving motor symptoms and cognitive function. Its α₂-adrenergic antagonism may contribute to vasodilation.
- Pharmacokinetics: Piribedil is administered orally and is absorbed in the gastrointestinal tract. Food may enhance its absorption. Peak plasma concentration is generally reached in about one hour. It has low bioavailability (approximately 10%).
- Mode of Action: Binds to and activates D₂ and D₃ dopamine receptors, mimicking the effects of dopamine. It also blocks α₂-adrenergic receptors.
- Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: D₂ and D₃ receptor agonist; α₂-adrenergic receptor antagonist.
- Elimination Pathways: Although specific details were not found in the provided resources, the primary metabolic pathway is not hepatic. Limited available information suggests it is not cleared through CYP enzymes. Further investigation is needed to provide precise details.
Dosage
Standard Dosage
Adults:
- Monotherapy: 150-250 mg daily, divided into 3-5 doses.
- Adjunctive Therapy with Levodopa: 50-150 mg daily (approximately 20 mg of piribedil per 100 mg of levodopa), divided into multiple doses. It is advised to commence at 50 mg daily, escalating by 50 mg every three days until the desired effect is observed.
- Administer with food.
Children:
The safety and efficacy of piribedil in children under 18 have not been established and its use is not recommended.
Special Cases:
- Elderly Patients: Start with a lower dose and titrate cautiously.
- Patients with Renal Impairment: Exercise caution; no specific dosage adjustment guidelines are available.
- Patients with Hepatic Dysfunction: Exercise caution; no specific dosage adjustment guidelines are available.
- Patients with Comorbid Conditions: Use with caution in patients with cardiovascular disease, hypertension, and psychiatric disorders.
Clinical Use Cases
- Information about dosage in clinical use cases such as intubation, surgical procedures, mechanical ventilation, and ICU use, as well as emergency situations, was not found in the given material.
Dosage Adjustments
- Adjust dosage based on individual patient response and tolerability.
Side Effects
Common Side Effects
- Nausea, vomiting, flatulence, dizziness, drowsiness, orthostatic hypotension.
Rare but Serious Side Effects
- Hallucinations, confusion, agitation, impulse control disorders (pathological gambling, compulsive buying, hypersexuality), dyskinesia, syncope, neuroleptic malignant syndrome (upon abrupt discontinuation), peripheral edema, sleep disorders.
Long-Term Effects
- Information regarding long-term effects was not found in the provided source material.
Adverse Drug Reactions (ADR)
- As mentioned above, some ADRs needing immediate intervention include neuroleptic malignant syndrome, severe hypotension, and serious impulse control disorders.
Contraindications
- Hypersensitivity to piribedil, acute myocardial infarction, cardiogenic shock, concurrent use with antiemetic neuroleptics.
Drug Interactions
- Antiemetic Neuroleptics: Can cause reciprocal antagonism and should be avoided.
- Antipsychotics: May reduce the effectiveness of piribedil.
- Antihypertensives: May increase the risk of orthostatic hypotension.
- Levodopa: May enhance therapeutic effects but also increase the risk of side effects.
- Sedatives: Increased risk of sedation.
- Tetrabenazine: May diminish the therapeutic effects of piribedil.
- Alcohol: May enhance sedative effects and should be avoided.
Pregnancy and Breastfeeding
- Pregnancy: Not recommended due to limited safety data.
- Breastfeeding: Not recommended as it may inhibit lactation and its presence in breast milk is unknown.
Drug Profile Summary
- Mechanism of Action: Dopamine D₂ and D₃ receptor agonist; α₂-adrenergic receptor antagonist.
- Side Effects: Nausea, vomiting, dizziness, drowsiness, orthostatic hypotension; rarely hallucinations, confusion, impulse control disorders.
- Contraindications: Acute myocardial infarction, cardiogenic shock, concurrent use with antiemetic neuroleptics.
- Drug Interactions: Antiemetic neuroleptics, antipsychotics, antihypertensives, levodopa, sedatives, tetrabenazine, alcohol.
- Pregnancy & Breastfeeding: Not recommended.
- Dosage: Adults: 150-250 mg/day (monotherapy), 50-150 mg/day (with levodopa), divided into 3-5 doses.
- Monitoring Parameters: Blood pressure, impulse control disorders.
Popular Combinations
- Levodopa: Used to enhance the management of Parkinson’s disease, but necessitates careful monitoring due to increased potential for side effects.
Precautions
- General Precautions: Monitor blood pressure, assess for history of cardiovascular disease or psychiatric disorders.
- Specific Populations: Use with caution in elderly patients and those with renal or hepatic impairment. Avoid in pregnant and breastfeeding women.
- Lifestyle Considerations: Avoid alcohol. Patients should not drive or operate heavy machinery if experiencing drowsiness or sudden sleep onset.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Piribedil?
A: Adults: 150-250 mg/day (monotherapy) or 50-150 mg/day (with levodopa), divided into 3-5 doses. Administer with food. Pediatric use is not recommended.
Q2: What are the common side effects of Piribedil?
A: Nausea, vomiting, flatulence, dizziness, drowsiness, and orthostatic hypotension are common side effects.
Q3: What are the serious side effects of Piribedil that require attention?
A: Hallucinations, confusion, agitation, impulse control disorders, dyskinesia, syncope, and neuroleptic malignant syndrome (upon abrupt discontinuation) are rare but serious side effects that require medical attention.
Q4: Is Piribedil safe during pregnancy and breastfeeding?
A: Piribedil is not recommended during pregnancy and breastfeeding due to limited safety data.
Q5: Can Piribedil be taken with other Parkinson’s medications?
A: Yes, it can be used with levodopa, but it’s important to monitor for increased side effects. It should not be combined with antiemetic neuroleptics.
Q6: How does Piribedil work in Parkinson’s disease?
A: Piribedil stimulates dopamine D₂ and D₃ receptors in the brain, compensating for the dopamine deficiency that characterizes Parkinson’s disease.
Q7: What should patients avoid while taking Piribedil?
A: Patients should avoid alcohol and activities requiring alertness (driving, operating machinery) if they experience drowsiness or sudden sleep onset. They should avoid antiemetic neuroleptics.
Q8: Are there any specific monitoring parameters for patients on Piribedil?
A: Blood pressure should be monitored, particularly at the start of therapy. Regularly assess for the development of impulse control disorders.
Q9: What should be done in case of Piribedil overdose?
A: Overdose can lead to hypotension or hypertension, nausea, and vomiting. Management is primarily symptomatic.
Q10: Does Piribedil interact with antipsychotic medications?
A: Yes, Piribedil can interact with antipsychotic medications, potentially decreasing its effectiveness. This should be considered when co-prescribing.
