Ropinirole in the Requip form is available in various preparations, ranging from a 0.25 mg tablet to a 5 mg tablet. The primary reason is dose titration. This implies that the person taking Requip has to closely interact and communicate with the primary care physician with regard to how much should actually be taken by the patient.
For Parkinson's disease, the maximum recommended dose is 24 mg per day, taken in three separate doses spread throughout the day. The maximum dose recommendations of ropinirole for subjects with end stage renal disease (ESRD) should be reduced by 25% compared with those recommended for subjects with normal renal function. A 25% dose reduction represents a more straightforward dosage regimen in terms of available tablet strength, compared with a 30% dose reduction.
For RLS, the maximum recommended dose is 4 mg per day, taken 1 to 3 hours before bedtime. A 52-week open label study had a mean dosage of 1.90 mg, once daily 1 to 3 hours before bedtime.
Ropinirole is metabolized primarily by cytochrome P450CYP1A2 to form two metabolites; SK&F-104557 and SK&F-89124, both of which are renally excreted, and at doses higher than clinical, is also metabolized by CYP3A4. At doses greater than 24 mg, CYP2D6 may be inhibited, although this has only been tested in vitro.
In November 2012, GlaxoSmithKline was ordered by a Rennes appeals court to pay Frenchman Didier Jambart 197,000 euros ($255,824); Jambart had taken ropinirole from 2003 to 2010 and exhibited risky hypersexual behavior and gambled excessively until stopping the Parkinson's treatment.
^ abcdTompson, Debra J. et al. (2007). "Steady-State Pharmacokinetic Properties of a 24-Hour Prolonged-Release Formulation of Ropinirole: Results of Two Randomized Studies in Patients with Parkinson’s Disease". Clinical Pharmacokinetics29 (12): 2654–66. doi:10.1016/j.clinthera.2007.12.010. PMID18201581.
^Lipp, Elizabeth (2008-08-01). "Novel Approaches to Lead Optimization". Genetic Engineering & Biotechnology News. Drug Discovery 28 (14) (Mary Ann Liebert). p. 20. ISSN1935-472X. Retrieved 2008-09-28.Note: The opinion that ropinirole's use in RLS was a successful example of drug repurposes was reported as being that of Josef Scheiber, a post-doctoral fellow at the Novartis Institutes for BioMedical Research.
^Gallagher, G.; Lavanchy, P. G.; Wilson, J. W.; Hieble, J. P.; Demarinis, R. M. (1985). "4-[2-(Di-n-propylamino)ethyl]-2(3H)-indolone: A prejunctional dopamine receptor agonist". Journal of Medicinal Chemistry28 (10): 1533. doi:10.1021/jm00148a028. PMID4045928.edit