Catechol-O-methyltransferase inhibition with tolcapone reduces the "wearing off" phenomenon and levodopa requirements in fluctuating parkinsonian patients.
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Resumo
BACKGROUND
More than 50% of patients with Parkinson's disease develop motor response fluctuations (the "wearing off" phenomenon) after more than five years of levodopa therapy. Inhibition of catechol-O-methyltransferase by tolcapone has been shown to increase levodopa bioavailability and plasma elimination half life, thereby prolonging the efficacy of levodopa.
OBJECTIVE
The primary objective was to evaluate the efficacy of tolcapone in reducing "wearing off" in levodopa treated, fluctuating parkinsonian patients. Secondary objectives included assessment of reduction in levodopa requirements, improvement in patients' clinical status, duration of improvements, and tolerability of tolcapone.
METHODS
In this multicentre, randomised, double blind, placebo controlled trial, 58 patients received placebo, 60 received 100 mg tolcapone three times daily (tid), and 59 received 200 mg tolcapone tid, in addition to levodopa/benserazide.
RESULTS
After three months with 200 mg tolcapone tid, "off" time decreased by 26.2% of the baseline value, "on" time increased by 20.6% (P CONCLUSIONS Tolcapone prolongs "on" time in fluctuating parkinsonian patients while allowing a reduction in daily levodopa dosage, thereby improving the efficacy of long term levodopa therapy.
