Acute levodopa administration reduces cortisol release in patients with Parkinson's disease.

Levodopa (LD) application improves motor symptoms in patients with Parkinson's disease (PD) patients. Little is known on further effects of LD, which induced lower plasma levels of cortisol and lower serotonergic activity in certain brain areas of fish. Objectives of this trial were to analyse levels of cortisol, LD and 3-O-methyldopa (3-OMD) after administration of LD/benserazide in long term treated PD patients. 12 PD patients, taken off their regular treatment for at least 12 hours, received soluble 200 mg LD/50 mg benserazide under stress free conditions. Motor symptoms improved, LD and 3-OMD levels increased, whereas cortisol concentrations started to decrease significantly 30 minutes after LD intake. This reduced cortisol release may result from an overflow of exogenous LD in the brainstem. This hypothetically causes an reduced 5-HT content in neurons projecting to the hypothalamic structures, which are involved in the partial 5-HT dependent central regulation of peripheral cortisol release.

The DONPAD-study--treatment of dementia in patients with Parkinson's disease with donepezil.

Inhibition of acetylcholinesterase improves symptoms of dementia in patients with Parkinson's disease (PD). Dementia in PD has a cumulative incidence of up to 80% and is mainly caused by a distinct cholinergic deficit. Objectives of this investigator initiated multicenter open label trial were to confirm the efficacy of donepezil in the treatment of dementia in PD patients and to investigate the tolerability and safety of donepezil. The Mini Mental State Examination (MMSE)-score significantly increased in patients, who finished the trial. A detailed analysis of the various items of the MMSE revealed, that only task performance of orientation and recall significantly improved. Scores of the short syndrome test and the Clinical Global Impression Scale improved, motor impairment did not increase. Only 14 out of 24 PD patients finished the trial due to predominant onset of vomiting, nausea, dizziness and confusion. This may result from the titration regime of donepezil, that allows only 5 and 10 mg dosages. Participants with premature study termination had a significant longer duration of PD, less motivation and sleep disturbances at night. Treatment with donepezil was only effective in PD patients with dementia, who experience nearly no side effects from the drug.