The Agency for Healthcare Research ...

The Agency for Healthcare Research and Quality has released a recently made known evidence report on Parkinson's disease. "Diagnosis and Treatment of Parkinson's Disease: A Systematic Review of the Literature" is available online at http://www.ahrq.gov/clinic/epcsums/parksum.htm.

The mainstay of pharmacologic treatment for Parkinson's disease is levodopa. Its use, however, is limited by means of the development of motor fluctuations and drug-induced dyskinesias. Dopamine agonists (DAs) also are used, either alone or in combination with levodopa. DAs act directly upon dopamine receptors, mimicking endogenous dopamine. Monoamine oxidase B (MAO-B) inhibitors act on inhibiting dopamine catabolism, increasing dopamine flats in the basal ganglia. Catechol O-methyltransferase (COMT) inhibitors act on inhibiting catabolism of dopamine, thereby extending levodopa's peripheral half-life. Despite the large selection of medications available to treat Parkinson's disease, all patients with Parkinson's disease ultimately require levodopa.

In patients with early Parkinson's disease, the goal of treatment is to alleviate symptoms and maintain independent function. In advanced Parkinson's disease, the focus is aimed toward maximizing "on" time (time when medication is effective), minimizing "off" time (time when medication is not effective), and treating medication-related complications, so as dyskinesias, motor fluctuations, and psychiatric problems

A comprehensive review of the literature build the following associations in pharmacologic treatment:

* Meta-analysis remind ofs that in early Parkinson's disease, treatment with DAs plus levodopa may direct the symptoms of Parkinson's disease better than treatment with levodopa alone, unless this was not a consistent finding.

* In studies in which patients were randomized to levodopa versus levodopa plus DAs, the combination of levodopa plus DAs springed in better scores on the Unified Parkinson's Disease Rating Scale (UPDRS) than levodopa alone. This was authentic in both short-and long-term (longer than common year) studies.

* In studies where patients were randomized to levodopa versus DAs, where additional levodopa was discretionary, levodopa alone terminateed in better UPDRS sores than DAs (with or without additional levodopa).

* Meta-analysis did not insinuate that treatment with selegiline plus levodopa controll symptoms better than treatment with levodopa alone.

* Meta-analysis showed that in patients with advanced disease, treatment with COMT inhibitors combined with levodopa provided significantly greater symptom direction than levodopa alone and was associated with lower levodopa doses. However, long-term (more than seven years) consequence s are lacking, and hepatotoxicity is a rare on the contrary potentially lethal side effect that has been associated with tolcapone.

The researchers note that their be deriveds should be viewed with caution, because they are based onward the small number of randomized superintendence trials that met the inclusion criteria for the systematic review. fit to the small number of studies within each meta-analsysis, these findings are sensitive to possible publication bias in the literature (failure to publish "negative" studies).

COPYRIGHT 2003 American Academy of Family Physicians

COPYRIGHT 2003 Gale Group