Ropinirole

Ropinirole (marketed as Requip®) is a non-ergoline dopamine agonist, manufactured by GlaxoSmithKline. It is used in the treatment of Parkinson's disease, and is also one of two medications in the United States with an FDA-approved indication for the treatment of restless legs syndrome (the other being Pramipexole).

Dosing
Requip (it is marketed as Adartrel in Europe for the Restless Legs Syndrome indication and as Requip for the anti-Parkinson indication) is available in various preparations, ranging from the .25 mg tablet to the 5 mg tablet. The primary reason for such 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 Restless Legs Syndrome or RLS, the maximum recommended dose is 4 mg per day, taken 1 to 3 hours before bedtime.

For Parkinson's Disease or PD, the maximum recommended dose is 24 mg per day, taken in three separate doses spread throughout the day.

Mechanism
Ropinirole acts as an agonist at the D2 and D3 dopamine receptor subtypes, binding with higher affinity to D3 than to D2 or D4. It has negligible effect on D1-receptors. It has medium in vitro affinity to opioid receptors. Ropinirole is said to have virtually no affinity to 5-HT1, 5-HT2, benzodiazepine, GABA, muscarinic, α1-, α2-, and β-adrenoreceptors.