the encyclopedic entry of Piribedil

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Composition

Piribedil 50 mg per tablet - sustained-release.

Indications

Treatment of Parkinson's disease, either as monotherapy (without L-dopa) or in combination with L-dopa therapy, in the early stages as well as in the advanced stages.
Treatment of pathological cognitive deficits in the elderly (impaired attention, memory, etc). Treatment of dizziness in the elderly.
Treatment of retinal ischemic manifestations.
Adjuvant treatment in intermittent claudication due to peripheral occlusive arterial disease of the lower limbs (stage 2).
Anhedonia and treatment-resistant depression in unipolar and bipolar depressives (off label).

Dosage

Parkinson's disease

Administration of piribedil should be initiated with one tablet daily during the first week. Dosage should then be gradually increased every week until achieving the optimal therapeutic dose:

as monotherapy: three to five tablets in three to five doses daily.
in combination with L-dopa therapy: one to three tablets daily.

Other indications

One tablet daily at the end of the main meal. In severe cases: two tablets daily in two doses.

Adverse effects

Minor gastrointestinal disorders (nausea, vomiting, flatulence) in predisposed individuals, or when taken between meals: Adjust dosage individually, and/or add domperidone.
Orthostatic hypotension or drowsiness may occur, particularly in predisposed individuals (underlying condition or causative illness).

Interactions

Dopamine antagonists reduce the effect of piribedil.

Overdosage

At very high doses, piribedil has an emetic action on the chemoreceptor trigger zone. Tablets will thus be rapidly rejected, which explains why no data are currently available concerning the risk of overdosage.

Receptor affinities

Dopamine receptor agonist, selective for subtypes D₂ and D₃.
Adrenergic receptor antagonist, subtypes α_2a and α_2c: could be the reason why piribedil seems to cause less drowsiness than other dopamine agonists.
Lack of affinity to serotonin receptor 5-HT_2B: theoretically no risk of heart valve impairment.