Ropinirole
Ropinirole. Non-ergot dopamine agonist at D2 and D3 receptors; used in Parkinson's disease and restless legs syndrome. Hepatic CYP1A2 metabolism… Oral half-life 6 h.
Non-ergot dopamine agonist at D2 and D3 receptors; used in Parkinson's disease and restless legs syndrome. Hepatic CYP1A2 metabolism (interacts with CYP1A2 inhibitors/inducers).
PK from FDA prescribing information (DailyMed setid e32ef7a6-b4b6-4a22-a2ed-722255b486b4, IR film-coated tablet): absolute bioavailability 45–55% (F 0.50), apparent Vd 7.5 L/kg (~525 L at 70 kg), elimination t½ ~6 h, Tmax ~1–2 h, hepatic CYP1A2 metabolism. ka_hr 2.0 derived from Tmax ~1.5 h (ke from t½ 6 h). PK: F 0.5 AND t½ 6 ARE NOW CITABLE VERBATIM — "The bioavailability is approximately 50%" and "eliminated with a half-life of approximately 6 hours" — replacing a label-only row, though the source is a sponsor review rather than a primary. V 525 L is the label APPARENT volume of 7.5 L/kg scaled by weight, and the human intravenous arm that might have anchored a true one produced no usable curve: concentrations "were below the lower limit of quantification in man (0.08 ng/ml)". F is therefore pinned to 1 so the apparent volume is used as intended, and the measured 50% recorded here. A COLLISION TRAP CHECKED AND ABSENT: that same paper "nearly all of the p.o. administered dose (94%) was rapidly absorbed" is a fraction ABSORBED, not a bioavailability, and the record correctly stored 0.5 rather than 0.94. THE SMOKING HYPOTHESIS IS REPORTED AS A NEGATIVE: every ropinirole-and-smoking record is about impulse-control behaviour, not kinetics, and the review covariate list omits smoking entirely. ka 2.0 back-derives to 1.51 h, the midpoint of the label 1-2 h.
Pharmacokinetics
- Oral — t½ 6 h · F 100% · Vd 525 L
Sources: PMID:11069211, PMID:10219970, PMID:10455328, PMID:30362146