Comparative Pharmacology
Head-to-head clinical analysis: PARLODEL versus REQUIP.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PARLODEL versus REQUIP.
PARLODEL vs REQUIP
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dopamine D2 receptor agonist; inhibits prolactin secretion by binding to pituitary and hypothalamic D2 receptors.
Dopamine receptor agonist; exhibits high affinity for D2 and D3 receptors, and moderate affinity for D1 and D4 receptors.
Parkinson disease: initial 1.25 mg orally twice daily, increase by 2.5 mg/day every 2-4 weeks; usual range 15-30 mg/day. Hyperprolactinemia: initial 1.25-2.5 mg orally once daily, titrate to 2.5 mg twice daily; maintenance 2.5-15 mg/day.
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.
None Documented
None Documented
Terminal elimination half-life: 12-14 hours (biphasic, initial half-life 6-8 hours); clinical context: steady-state achieved in 2-3 days.
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.
Renal: approximately 60% as metabolites, 6% as unchanged drug; biliary/fecal: approximately 40% as metabolites and unchanged drug.
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%.
Category C
Category C
Dopamine Agonist
Dopamine Agonist