Lack of a pharmacokinetic interaction at steady state between ropinirole and L-dopa in patients with Parkinson's disease.

Autor: Taylor AC; Division of Drug Metabolism and Pharmacokinetics, SmithKline Beecham Pharmaceuticals, Welwyn, Herts, UK., Beerahee A, Citerone DR, Cyronak MJ, Leigh TJ, Fitzpatrick KL, Lopez-Gil A, Vakil SD, Burns E, Lennox G
Jazyk: angličtina
Zdroj: Pharmacotherapy [Pharmacotherapy] 1999 Feb; Vol. 19 (2), pp. 150-6.
DOI: 10.1592/phco.19.3.150.30927
Abstrakt: Study Objective: To assess the interaction between therapeutic dosages of ropinirole and L-dopa plus a decarboxylase inhibitor administered at steady state in patients with Parkinson's disease. DESIGN. Open, 6-week, overlap trial with random allocation.
Patients: Thirty patients with Parkinson's disease not previously treated with dopamine agonists, of whom 28 produced evaluable pharmacokinetic data for ropinirole and 23 for L-dopa.
Intervention: Group A (14 patients) received L-dopa for weeks 1-5 and ropinirole in increasing increments for weeks 2-6; group B (16) received ropinirole for weeks 1-5 and L-dopa for weeks 5 and 6.
Measurements and Main Results: Primary end points were AUC0-8 and Cmax for ropinirole, and AUC0-8, AUC0-infinity and Cmax for L-dopa. Secondary end points were Tmax for ropinirole, and Tmax and half-life for L-dopa. Coadministration with L-dopa at steady state did not affect rate or extent of availability of ropinirole: point estimates of the geometric mean ratio for ropinirole plus L-dopa compared with ropinirole alone for both Cmax and AUC0-8 approximated to unity. The small (16%) increase in peak concentrations of L-dopa on administration with ropinirole is unlikely to be of clinical consequence, as peak concentrations of L-dopa are typically highly variable.
Conclusion: There are no pharmacokinetic grounds for adjusting dosages of either ropinirole or L-dopa when given in combination.
Databáze: MEDLINE
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