BACKGROUND Dyskinesias are a frequent adverse effect of long-term levodopa therapy. The relative contribution of dopamine D(1) and D(2) receptor function to the pathophysiology of levodopa-induced dyskinesias remains a matter of controversy. OBJECTIVE To establish whether a selective D(1) dopamine agonist induces more or less dyskinesia than levodopa in primed dyskinetic patients with Parkins...

A controlled release preparation of levodopa-carbidopa, CR III, given every 4 hours to 17 Parkinsonian patients for up to 10 months reduced plasma drug variations and improved motor response fluctuations compared with standard levodopa-carbidopa given every 2 hours. The results support the value of pharmaceutical approaches to the stabilisation of circulating levodopa levels in the treatment of...

Three patients are reported who developed a melanoma while taking levodopa for Parkinson's disease. There were two cutaneous melanomas and one metastatic melanoma with occult primary. The literature on the association of Parkinson's disease, levodopa therapy and melanoma is reviewed. The capacity of levodopa to induce melanomas and its alleged adverse effect on the clinical course of the diseas...

Growth hormone and prolactin response to levodopa were evaluated before and after long-term phenytoin treatment in five men with previously untreated partial epilepsy. After phenytoin treatment, growth hormone response to levodopa increased. There was a close relationship between growth hormone response to levodopa and plasma phenytoin concentrations. These findings suggest a phenytoin-induced ...

There is a consensus that in Parkinson's disease, the extent of preoperative levodopa responsiveness predicts the efficacy of subthalamic nucleus deep brain stimulation (STN DBS). However, this may be the result of statistical methods and primary assumptions. We were able to reproduce previously published correlation results on our data (N = 49 patients). Yet, these same results were demonstrat...

Recent studies in animal models of Parkinson's disease (PD) have provided evidence that dopamine released from spared serotonin afferents can act as a trigger of dyskinetic movements induced by repetitive, low doses of levodopa. Serotonin neurons have the capacity to store and release dopamine synthesized from systemically administered levodopa. However, because of the lack of any autoregulator...

The aim of this study is to clarify the relationship between serum 3-O-methyldopa (3-OMD) and the clinical effects of entacapone. The 3-OMD and maximum serum concentration (Cmax) of levodopa were measured in 21 Parkinson's Disease patients who took 100 mg levodopa / dopa decarboxylase inhibitor. After the administration of entacapone, the 3-OMD concentration and percentage of "on" time during w...

Diabetes Increases the Incidence of Levodopa-Induced Dyskinesia in Parkinson’s Disease; A Case-Control Study

Levodopa medication is the most efficient treatment for motor symptoms of Parkinson's disease (PD). Levodopa significantly alleviates rigidity, rest tremor, and bradykinesia in PD. The severity of motor symptoms can be graded with UPDRS-III scale. Levodopa challenge test is routinely used to assess patients' eligibility to deep-brain stimulation (DBS) in PD. Feasible and objective measurements ...

Objectives-To establish, in a double blind manner, the antiparkinsonian effects of repeated dosing with entacapone, a peripheral COMT inhibitor. Methods-A one month, cross over study was conducted. During the two four-week treatment periods, entacapone (200 mg) or placebo was given with each levodopa dose four to 10 times daily. Motor responses were repeatedly quantified using the motor part of...