Comparative Pharmacology
Head-to-head clinical analysis: MIRAPEX versus REQUIP XL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MIRAPEX versus REQUIP XL.
MIRAPEX vs REQUIP XL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dopamine receptor agonist (D3 > D2 > D4) with activity at α2-adrenergic and 5-HT1A receptors; increases dopamine receptor activation in striatum.
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.
Initial: 0.375 mg orally once daily; titrate gradually based on efficacy and tolerability. Usual effective dose: 1.5-4.5 mg daily in 3 divided doses. Maximum dose: 4.5 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
The terminal elimination half-life is 8–12 hours in healthy adults, allowing for three-times-daily dosing. In elderly patients, half-life may be prolonged to 12–14 hours due to age-related decline in renal function.
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.
Renal elimination accounts for approximately 90% of total clearance, with about 80% recovered as unchanged parent drug in urine. Biliary/fecal excretion is minimal (<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