Comparative Pharmacology
Head-to-head clinical analysis: APOKYN versus REQUIP XL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: APOKYN versus REQUIP XL.
APOKYN vs REQUIP XL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Apomorphine is a non-ergoline dopamine agonist that stimulates dopamine D2 and D1 receptors. It also activates D3, D4, and D5 receptors and has some serotonergic and adrenergic activity.
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.
Subcutaneous injection: 0.2 mL (2 mg) as a test dose, then 0.1-0.6 mL (1-6 mg) as needed for episodes of hypomobility; maximum single dose: 0.6 mL (6 mg); maximum daily dose: 2.0 mL (20 mg).
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 30–60 minutes (range 0.5–1 hour); clinically, rapid clearance necessitates continuous or frequent dosing for sustained effect
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 (approx. 90% as metabolites and unchanged drug; <5% unchanged in urine); biliary/fecal (minor, <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