Trivastal Retard 50 mg — Piribedil
1- Disclaimer
This information is intended for general educational and reference purposes and is not a substitute for the advice of a qualified physician, pharmacist, or other healthcare professional. Trivastal Retard 50 mg is a prescription medicine, and treatment decisions, dosing, dose adjustments, discontinuation, and management of adverse effects should be individualized by the treating clinician.
We do not guarantee the accuracy, currency or completeness of information regarding medications or medical products, and official sources should be verified before making any decisions. Readers are responsible for independently verifying the information before relying on it.
Product information, approved indications, availability, packaging, and regulatory status may differ between countries and may change over time. The applicable Egyptian approved product information should therefore be consulted for use in Egypt.
2- Summary
Trivastal Retard 50 mg contains piribedil, a non-ergot dopaminergic agonist supplied as a sustained/prolonged-release oral tablet. Its principal established therapeutic use in current regulatory product information is the symptomatic treatment of Parkinson’s disease, either as monotherapy in appropriate patients or in combination with levodopa. Piribedil stimulates dopaminergic pathways and has a pharmacological profile characterized by activity at dopamine D2/D3 receptors together with α2-adrenoceptor antagonism.
The most clinically important safety issues include somnolence and rare sudden sleep episodes, orthostatic hypotension, hallucinations or other psychotic symptoms, abnormal behavior, impulse-control disorders, dyskinesia, peripheral oedema, and adverse effects associated with abrupt withdrawal of dopaminergic therapy.
3- Brand Name
Trivastal Retard 50 mg
The product is also described in regulatory records as TRIVASTAL RETARD 50, a sustained-/prolonged-release coated tablet. Current Singapore government product information lists the same-strength product as a 50 mg film-coated tablet manufactured by Les Laboratoires Servier Industrie, France.
4- Category
Pharmacological category: Dopaminergic agonist / antiparkinsonian medicine.
ATC classification: N04BC08 — Piribedil.
Some Egyptian commercial drug listings classify Trivastal Retard under “anti-ischemic” products, reflecting its historical/peripheral vascular classification. Nevertheless, its formal pharmacotherapeutic classification in current regulatory information is dopaminergic agonist, and its principal established current indication is Parkinson’s disease.
5- Active Ingredient
Piribedil — 50 mg per sustained-/prolonged-release coated tablet.
Piribedil is a non-ergot dopamine agonist. Pharmacological literature describes it principally as a D2/D3-selective partial agonist with α2-adrenoceptor antagonist properties.
6- Pharmaceutical Form & Strength
Dosage form: Sustained-/prolonged-release coated tablet.
Strength: 50 mg piribedil per tablet.
The prolonged-release formulation is designed to provide sustained release and absorption of piribedil and has been associated with therapeutic coverage extending beyond 24 hours in pharmacokinetic studies described in the product information.
7- Manufacturer & Marketing Authorization Holder
For the Egyptian product information supplied with this product, the manufacturer is identified as:
SERVIER EGYPT INDUSTRIES LIMITED
6th October City, Giza, Arab Republic of Egypt
Under licence of Les Laboratoires Servier, France.
Current international regulatory records for the same Trivastal Retard 50 mg product identify Les Laboratoires Servier Industrie, France as manufacturer, while the Singapore product record identifies Servier (S) Pte Ltd as the local licence holder there.
The Egyptian-specific current marketing authorization holder could not be independently confirmed from a currently indexed public EDA brand-specific record; therefore, it should not be stated more specifically without reference to the current Egyptian approved pack/registration documentation.
8- Mechanism of Action
Piribedil increases dopaminergic neurotransmission by stimulating dopamine receptors and dopaminergic pathways in the brain. More detailed pharmacological studies characterize it as a partial agonist at dopamine D2 and D3 receptors and an antagonist at α2-adrenoceptors.
This dopaminergic activity helps compensate for deficient dopaminergic signaling in Parkinson’s disease and can improve motor manifestations such as tremor, rigidity, and bradykinetic symptoms.
The product information also describes an increase in femoral blood flow, consistent with dopaminergic effects on peripheral vascular receptors; however, this pharmacological observation should not be interpreted as establishing a modern cardiovascular indication unless that indication is specifically included in the applicable national approved product information.
9- Spectrum of Activity
Not applicable in the antimicrobial sense.
Trivastal is not an antibiotic, antiviral, antifungal, or anti-infective medicine, so it does not have an antimicrobial “spectrum of activity.”
Its pharmacological activity is primarily dopaminergic, particularly involving D2/D3 receptors, with additional α2-adrenoceptor antagonism.
10- Pharmacokinetics
Piribedil is rapidly absorbed after oral administration. According to the product information, peak plasma concentration is reached approximately 1 hour after oral dosing. Plasma elimination is biphasic, with an initial half-life of approximately 1.7 hours followed by a slower phase with a half-life of approximately 6.9 hours.
Piribedil undergoes extensive metabolism, producing two principal metabolites described as hydroxyl and dihydroxyl derivatives. Approximately 68% of absorbed piribedil is excreted through the kidneys as metabolites, while approximately 25% is eliminated through the bile.
The 50 mg sustained-release formulation prolongs release and absorption of the active substance. Product pharmacokinetic studies reported therapeutic coverage extending for more than 24 hours, with urinary elimination approximately 50% complete by 24 hours and essentially complete by 48 hours.
Patients with hepatic or renal impairment were not adequately investigated in the cited product information; therefore, caution is advised in these populations.
11- Indications
Current clearly supported indication
Parkinson’s disease:
- as monotherapy in appropriate patients, particularly essential forms with tremor;
- or in combination with levodopa, from the outset or subsequently, particularly in forms with tremor.
An important distinction is necessary regarding the older Egyptian leaflet text: it also listed age-related minor neurological disorders, adjunctive treatment of lower-limb arteritis, and visual disorders of circulatory origin. Those indications appear in older product information, but they are not included in the newer regulatory product information reviewed here, which specifies Parkinson’s disease.
Accordingly, those older indications should not be presented as definitively current approved indications in Egypt unless they are confirmed in the current Egyptian approved leaflet.
12- Administration
Trivastal Retard 50 mg is administered orally.
The tablet should be swallowed whole, without chewing, with approximately half a glass of water, at the end of a meal.
For Parkinson’s disease, the cited product information gives:
Monotherapy: 150–250 mg daily, equivalent to 3–5 tablets daily, divided into 3–5 administrations.
With levodopa: approximately 80–140 mg piribedil daily, with the product information stating approximately 20 mg piribedil for each 100 mg levodopa.
Treatment is initiated and/or increased gradually. The referenced product information describes increasing by one tablet every three days. The exact regimen must be determined by the prescriber rather than self-adjusted.
Treatment should not be stopped abruptly. Dopaminergic therapy should be reduced gradually because abrupt withdrawal may be associated with neuroleptic malignant syndrome.
13- Method of Preparation
No reconstitution or special preparation is required.
This is a ready-to-use sustained-release tablet. It should be swallowed whole with water and must not be chewed. Crushing, breaking, or otherwise altering a sustained-release dosage form should be avoided unless the current product information specifically permits it.
14- Contraindications
Trivastal Retard 50 mg is contraindicated in the following situations:
- Hypersensitivity to piribedil or any of the excipients.
- Cardiovascular shock/collapse.
- Acute myocardial infarction.
- Concomitant use with antiemetic neuroleptics.
The cited product information also contraindicates concomitant treatment with neuroleptics other than clozapine.
Because regulatory wording can differ between jurisdictions and product versions, the exact contraindications on the current Egyptian approved leaflet should be checked before prescribing or dispensing.
15- Warnings & Precautions
Sudden sleep onset and somnolence
Piribedil can cause somnolence and, very rarely, sudden sleep episodes that may occur without adequate warning. Patients who experience somnolence or sudden sleep onset should not drive or operate machinery and should seek medical advice regarding dose reduction or discontinuation.
Orthostatic hypotension
Dopamine agonists can impair blood-pressure regulation and cause postural/orthostatic hypotension. Blood pressure should be monitored, particularly when treatment is initiated. In older patients, falls may result from hypotension, sudden sleep, or confusion.
Impulse-control disorders
Patients and caregivers should be informed about possible pathological gambling, increased libido, hypersexuality, compulsive spending/buying, binge eating, or compulsive eating. The lowest effective dose is recommended, and dose reduction or gradual discontinuation should be considered if such behavior appears.
Abnormal behavior and psychosis
Confusion, agitation, and aggression may occur. Dopaminergic agonists may also induce or worsen psychotic disorders, including delusions, delirium, and hallucinations.
Dyskinesia
In advanced Parkinson’s disease treated with levodopa, dyskinesia may appear during initial titration of piribedil. Dose reduction may be required if this occurs.
Peripheral oedema
Peripheral oedema has been observed with dopamine agonists, including piribedil.
Abrupt withdrawal
Abrupt discontinuation of dopaminergic therapy may produce serious withdrawal complications, including neuroleptic malignant syndrome. Gradual tapering is therefore recommended.
Excipients
The product contains sucrose and Ponceau 4R/cochineal red A (E124). Patients with rare hereditary fructose intolerance, glucose-galactose malabsorption, or sucrase-isomaltase insufficiency should not take the product. E124 may cause allergic reactions. The referenced SmPC also states that the product contains less than 1 mmol sodium (23 mg) per tablet.
16- Drug Interactions
Contraindicated or inappropriate combinations
Neuroleptics/antipsychotic drugs other than clozapine: Dopaminergic antiparkinsonian drugs and dopamine-blocking neuroleptics can pharmacologically antagonize each other. Neuroleptics may also worsen Parkinsonian symptoms, while dopamine agonists can precipitate or aggravate psychosis.
Neuroleptic antiemetics: Combination is contraindicated; when an antiemetic is required, an option without significant extrapyramidal effects should be selected by the clinician.
Tetrabenazine: The combination is not advisable because of reciprocal pharmacological antagonism.
Alcohol: Concomitant use is not advisable because it may increase impairment of alertness/sedation.
Other sedative medicines: Caution is advised because of potentially increased central nervous system depression and impaired alertness.
Patients should provide their physician or pharmacist with a complete list of prescribed medicines, over-the-counter medicines, and other products before treatment is started or changed.
17- Side Effects
The product information reports the following adverse effects:
Common:
- nausea;
- vomiting;
- flatulence;
- confusion;
- agitation;
- visual, auditory, or mixed hallucinations;
- dizziness.
Uncommon:
- hypotension;
- orthostatic hypotension, sometimes associated with syncope, malaise, or unstable blood pressure.
Very rare:
- excessive daytime somnolence and sudden sleep-onset episodes.
Frequency not known:
- aggression;
- psychotic disorders such as delusions or delirium;
- dyskinesia;
- peripheral oedema.
Impulse-control disorders may also occur, including pathological gambling, increased libido, hypersexuality, compulsive buying/spending, binge eating, or compulsive eating.
An allergic reaction may occur because of Ponceau 4R/cochineal red A (E124).
18- Use in Special Populations
Pregnancy
Relevant human data are limited. Animal data did not indicate direct or indirect harmful effects on embryofetal development, parturition, or postnatal development; however, piribedil crosses the placental barrier in pregnant mice. In the absence of adequate human data, the cited product information does not recommend use during pregnancy.
Breast-feeding
Because adequate data are lacking, the cited product information does not recommend use during breast-feeding.
Fertility
Available animal studies did not indicate direct or indirect harmful effects on fertility-related reproductive development.
Renal impairment
Piribedil has not been adequately investigated in patients with renal impairment in the cited product information. Caution is advised.
Hepatic impairment
Piribedil has likewise not been adequately investigated in hepatic impairment. Caution is advised.
Children and adolescents
Safety and efficacy in patients under 18 years of age have not been established, and there is no established relevant pediatric use for the cited indication.
Elderly patients
Particular attention is warranted because falls may be promoted by orthostatic hypotension, sudden sleep episodes, dizziness, or confusion.
19- Storage Conditions
The cited current regulatory product information specifies:
Store below 25°C.
Keep the medicine out of the sight and reach of children.
The product should remain in its original packaging and should not be used after the expiry date stated on the package.
The older Egyptian leaflet supplied with the question states storage below 30°C, demonstrating a difference between older and newer product information. For a currently purchased Egyptian pack, the storage condition printed on the current authorized Egyptian packaging/leaflet should take precedence.
20- Additional Sections
Overdose
Excessive piribedil ingestion may cause blood-pressure instability, including hypertension or hypotension, together with gastrointestinal symptoms such as nausea and vomiting. Very high doses may have an emetic effect, making severe tablet overdose less likely, but suspected overdose still requires prompt medical assessment.
Driving and operating machinery
Patients who develop somnolence or sudden sleep episodes must not drive or operate machinery until these effects have resolved and medical advice has been obtained.
Missed dose
A missed dose should not ordinarily be compensated for by taking an unscheduled double dose. The patient should follow the prescribed schedule and obtain professional advice for repeated missed doses.
Withdrawal
Piribedil should not be stopped abruptly. Gradual dose reduction is recommended because abrupt withdrawal of dopaminergic therapy can cause serious withdrawal complications, including neuroleptic malignant syndrome.
Current Egyptian-market presentation
Current Egyptian retail listings identify Trivastal Retard 50 mg, 30 tablets, containing piribedil 50 mg. At the same time, availability can vary between pharmacies. Egyptian Drug Authority public documents have also listed piribedil 50 mg extended-release tablets, supporting the continued presence of the active ingredient/formulation in Egyptian pharmaceutical records.
The frequently encountered Egyptian classification “Anti-ischemic” should not be confused with the principal formal pharmacotherapeutic class of piribedil, which is dopaminergic agonist / antiparkinsonian drug.
21- Frequently Asked Questions (FAQ)
What is Trivastal Retard 50 mg used for?
Its clearly supported current regulatory indication is the symptomatic treatment of Parkinson’s disease, as monotherapy in appropriate patients or in combination with levodopa.
What is the active ingredient?
Each tablet contains 50 mg of piribedil.
Is Trivastal a dopamine agonist?
Yes. Piribedil is a non-ergot dopaminergic agonist with D2/D3 receptor activity and α2-adrenoceptor antagonist properties.
Can the Retard tablet be crushed or chewed?
No. It is a sustained-/prolonged-release formulation and should be swallowed whole without chewing.
Should Trivastal be taken with food?
Yes. The cited product information instructs patients to take the tablet at the end of a meal with water.
Can Trivastal cause sleepiness?
Yes. Somnolence can occur, and very rare sudden sleep-onset episodes have been reported. Anyone experiencing these effects should not drive or operate machinery.
Can Trivastal cause unusual or compulsive behavior?
Yes. Dopamine agonists including piribedil can cause impulse-control disorders such as pathological gambling, hypersexuality, compulsive spending, and compulsive eating.
Can Trivastal be stopped suddenly?
It should not normally be stopped abruptly. Gradual dose reduction is recommended because abrupt withdrawal of dopaminergic therapy may result in serious complications, including neuroleptic malignant syndrome.
Can it be used during pregnancy or breast-feeding?
Routine use is not recommended in the cited product information because relevant human safety data are insufficient.
Is Trivastal an anti-ischemic drug?
Some Egyptian commercial databases classify it that way, reflecting historical peripheral vascular use. However, its formal pharmacotherapeutic classification in current regulatory product information is dopaminergic agonist, and Parkinson’s disease is the clearly supported current indication in the newer product information reviewed here.
Is every indication in older Egyptian leaflets still current?
Not necessarily. Older Trivastal leaflets list age-related neurological disorders, lower-limb arteritis, and circulatory visual disorders, but these are absent from the newer regulatory product information reviewed. They should therefore not be described as currently approved without confirmation from the current Egyptian approved leaflet.
22- References
Medicines Authority Malta — Summary of Product Characteristics: TRIVASTAL RETARD 50 mg, sustained-release coated tablet. Contains detailed regulatory information on indications, dosage, contraindications, warnings, interactions, adverse effects, overdose, pharmacodynamics, and pharmacokinetics.
Singapore National Drug Formulary — TRIVASTAL RETARD 50 TABLET 50 MG. Government product record, last updated 28 July 2026, confirming piribedil 50 mg, film-coated tablet, manufacturer, ATC code, current indication, dosing, contraindications, and withdrawal precautions.
European Medicines Agency — List of nationally authorised medicinal products: piribedil (PSUSA). Confirms nationally authorized Trivastal 50 mg products and Servier authorization information in participating European jurisdictions.
Chaudhuri KR, Jenner P, Leta V, et al. The Movement Disorders Prescriber’s Guide to Parkinson’s Disease — Piribedil. Cambridge University Press, 2025. Describes piribedil as a non-ergot dopamine agonist and provides contemporary Parkinson’s pharmacological context.
Perez-Lloret S, Rascol O. Piribedil for the Treatment of Motor and Non-motor Symptoms of Parkinson Disease. CNS Drugs. Review of piribedil pharmacology and clinical evidence, including D2/D3 agonism and α2-adrenoceptor antagonism.
Egyptian Drug Authority — public pharmaceutical lists. Public EDA records have listed piribedil 50 mg tablets/extended-release tablets in Egyptian pharmaceutical documentation.
Current Egyptian retail listings for Trivastal Retard 50 mg, 30 tablets. Used only to corroborate current Egyptian market presentation/availability, not as a substitute for regulatory prescribing information.
Final accuracy note
The principal scientific corrections incorporated into this version are: Parkinson’s disease is treated as the clearly verified current indication; historical vascular/cerebral indications are not presented as currently approved without Egyptian confirmation; the contraindication/warning profile has been expanded; impulse-control disorders and psychotic/behavioral effects have been explicitly included; abrupt withdrawal is correctly treated as clinically important; and pharmacokinetic values have been taken from the detailed product characteristics rather than inferred from the old leaflet.