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Clinical pharmacokinetics of ropinirole
1Drug Metabolism and Pharmacokinetics, SmithKline Beecham Pharmaceuticals, Welwyn, Herts, England. clive_m_kaye@sbphrd.com
Clinical Pharmacokinetics
|November 9, 2000
Summary
Ropinirole, a dopamine agonist for Parkinson's disease, is well-absorbed orally and primarily metabolized by CYP1A2. Its pharmacokinetics are generally unaffected by patient factors but show slower clearance in older adults and women on hormone therapy.
Area of Science:
- Pharmacology
- Neuroscience
Background:
- Ropinirole is a selective non-ergoline dopamine D2 receptor agonist.
- It is indicated for the treatment of Parkinson's disease.
Purpose of the Study:
- To describe the pharmacokinetics of ropinirole.
- To identify factors influencing ropinirole's absorption, distribution, metabolism, and elimination.
Main Methods:
- Oral administration of ropinirole.
- Analysis of plasma concentrations and pharmacokinetic parameters.
- Population pharmacokinetic modeling.
Main Results:
- Ropinirole is rapidly absorbed with approximately 50% bioavailability.
- Metabolism occurs primarily via CYP1A2 in the liver.
- Pharmacokinetics are generally linear and unaffected by gender, mild/moderate renal impairment, or disease stage.
- Clearance is slower in patients >65 years and women on hormone replacement therapy.
- Ciprofloxacin (CYP1A2 inhibitor) increased ropinirole plasma concentrations; theophylline showed no interaction.
Conclusions:
- Ropinirole exhibits predictable pharmacokinetics.
- Age and hormone replacement therapy are factors influencing ropinirole clearance.
- Potential for drug interactions exists with CYP1A2 inhibitors.
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