Comparative Pharmacology
Head-to-head clinical analysis: REQUIP versus REQUIP XL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: REQUIP versus REQUIP XL.
REQUIP vs REQUIP XL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dopamine receptor agonist; exhibits high affinity for D2 and D3 receptors, and moderate affinity for D1 and D4 receptors.
Ropinirole is a non-ergoline dopamine agonist with high relative in vitro specificity and full intrinsic activity at the D2 subfamily of dopamine receptors, binding with higher affinity to D3 than to D2 or D4 receptor subtypes. The relevance of D3 receptor binding in Parkinson's disease is unknown.
Immediate-release: Initial 0.25 mg orally three times daily; titrate weekly by 0.25 mg per dose to a total daily dose of 3 mg; max 24 mg/day. Extended-release: Initial 2 mg orally once daily; titrate by 2 mg/day at weekly intervals; max 24 mg/day.
Initial: 2 mg orally once daily for weeks 1-2, then titrate as needed; maintenance: 8-24 mg orally once daily.
None Documented
None Documented
Terminal elimination half-life: approximately 5-6 hours in young healthy adults, extending to 7-9 hours in elderly patients. Clinically, dosing is typically three times daily due to this short half-life.
Approximately 6 hours (range 4-8 hours) for ropinirole; terminal half-life in elderly or hepatic impairment may be prolonged up to 10-12 hours. Clinically, steady-state achieved within 2 days of dosing.
Primarily renal: approximately 90% of the dose is excreted in urine, with about 60% as unchanged drug and 30% as metabolites. Fecal excretion accounts for about 10%.
Renal: 60% (mainly metabolites, <10% unchanged); fecal/biliary: 20%; total excretion accounts for >80% of dose.
Category C
Category C
Dopamine Agonist
Dopamine Agonist