ORIGINAL ARTICLESApomorphine Infusion and the Long-Duration Response to Levodopa in Advanced Parkinson's DiseaseStocchi, Fabrizio*; Berardelli, Alfredo*†; Vacca, Laura†; Barbato, Luca‡; Monge, Alessandra‡; Nordera, Giampietro‡; Ruggieri, Stefano*†Author Information *Institute of Neurology IRCCS “NEUROMED,” Pozzilli (IS); the †Department of Neurological Sciences, Rome, University of Rome, “La Sapienza”; and the ‡Institute “A. Benedetti” Vicenza, Italy Address correspondence and reprint requests to Dr. Fabrizio Stocchi, Department of Neurosciences, University “La Sapienza,” Viale dell'Università, 30, 00185, Rome Italy; e-mail: email@example.com Clinical Neuropharmacology: May-June 2003 - Volume 26 - Issue 3 - p 151-155 Buy Abstract The authors investigated the long-duration response to levodopa in advanced Parkinson's disease. Eight patients with advanced Parkinson's disease disabled by severe ON/OFF fluctuations treated by chronic daytime subcutaneous apomorphine infusion with supplemental oral levodopa were studied. On day 1, oral levodopa was withdrawn at 4:00 pm and on the following morning subcutaneous apomorphine infusion was continued at the same rate without levodopa therapy. While receiving apomorphine alone, seven of the eight patients turned ON, and their usual dyskinesias returned. The ON phase persisted for 60 to 100 minutes (mean, 185.7 minutes) but then, despite continued, constant-rate apomorphine infusion to stabilize plasma levels, switched to an OFF phase. The authors conclude that the clinical effect of apomorphine is sustained by levodopa long-duration response. This effect is probably the result of postsynaptic mechanisms. In patients with advanced Parkinson's disease, the long-duration response to levodopa is present although slightly diminished. © 2003 Lippincott Williams & Wilkins, Inc.