Oral pulse levodopa therapy for Parkinson's disease - Tips from Other Journals

Date: Oct, 1993

In patients with Parkinson's disease, it has been hypothesized that the period of effectiveness of a single dose of levodopa is longer than the interval between doses of the drug as conventionally given. Conventional therapy may, therefore, lead to overmedication in these patients. Quattrone and Zappia attempted to identify a levodopa regimen that would reduce side effects of long-term therapy for Parkinson's disease while retaining the drug's benefits.

Seven patients with mild Parkinson's disease were entered into a double-blind, crossover trial utilizing four different doses of levodopa plus carbidopa, each given for 15 days. The disease duration ranged from eight to 61 months. Three of the patients had never received any antiparkinsonian therapy, and the other four had received levodopa for four to 12 months. The subjects were selected it their baseline movement time improved following an acute levodopa test (250 mg of levodopa and 25 mg of carbidopa given orally).

Three of the four treatments were variations of the convetional doses of levodopa and carbidopa (given in a ratio of 10:1). The first treatment consisted of 62.5 mg of levodopa three times daily, the second, 125 mg three times daily, and the third, 187.5 mg three times daily. The fourth treatment, oral pulse levodopa therapy, consisted of 250 mg of levodopa once every three days. An anticholinergic, biperiden (2 mg three times daily), was also given with each of these four treatments. Movement times were measured during the last three days of each regimen, and the clinical condition of each patient was evaluated using the motor section of the Unified Parkinson's Disease Rating Scale.

Oral pulse levodopa therapy was, on average, more effective than either the first or second treatment. When compared with the third treatment, oral pulse levodopa therapy was as effective on the day the pulse was given and on the next day, but was less effective on the third day.

The authors conclude that the potential for minimizing the long-term side effects of chronic levodopa therapy is great with oral pulse therapy, although a shorter pulse dosing interval may be needed (possibly tailored to each patient's response to the acute levodopa test). This regimen may work by preserving compensatory mechanisms normally present in the brain. In effect, pulse therapy may act as a frequent "mini" drug holiday, and may aid in restoring levodopa responsiveness. Larger doses of levodopa given less often may prove beneficial for patients with excessive involuntary movement due to chronic levodopa administration.

COPYRIGHT 1993 American Academy of Family PhysiciansCOPYRIGHT 2004 Gale Group

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