Reduced renal clearance w/ medicinal products that are inhibitors of active renal elimination pathway or are eliminated by this pathway eg, cimetidine, amantadine, mexiletine, zidovudine, cisplatin, quinine, & procainamide. Possible additive effects w/ other sedating medicinal products or alcohol. Avoid co-administration w/ antipsychotic medicinal products eg, if antagonistic effects can be expected. When co-administered w/ levodopa, it is recommended that the dose of levodopa is reduced & the dose of other anti-parkinsonian medicinal products is kept constant while increasing the dose of Mirapex ER.