Long-term evaluation of amantadine and levodopa combination in parkinsonism by double-blind corssover analyses. The effect of adding amantadine to optimum L-dopa dosage in Parkinson's syndrome. Amantadine and levodopa in the treatment of Parkinson's disease. A qualitative and quantitative evaluation of amantadine in the treatment of Parkinson's disease. Double blind study using amantadine hydrochloride in the therapy of Parkinson's disease. Amantadine and a fixed combination of levodopa and carbidopa in the treatment of Parkinson's disease.
Twenty-three patients with Parkinson's disease participated in long-term, double-blind evaluations of the effectiveness and side effects of amantadine in combination with levodopa therapy. Sixteen patients completed the year-long study, which consisted of randomized crossover of amantadine and placebo before levodopa was begun and again after 5 and 11 months of continuous levodopa therapy. Initially, 16 of 23 patients (70 percent) had a favorable response to amantadine during the first crossover period. After 1 year of levodopa, at least eight of 16 patients (50 percent) responded favorably to amantadine compared with placebo. Some of the amantadine responders previously had been nonresponders, and vice versa. The response to amantadine was quantitatively similar in the responders even after the patients had been receiving levodopa therapy. Amantadine should be tried as a therapeutic agent in addition to levodopa for parkinsonism if more beneficial effect is desired, even if amantadine was previously ineffective in the same patient. nan nan nan nan Forty-two patients with Parkinson's disease were given amantadine HC1 (Symmetrel) and placebo in an 18 week double-blind cross-over study to determine if amantadine provided additional benefit when combined with levodopa and carbidopa (Sinemet). Analysis of our results showed that amantadine effected a 92% improvement over baseline in symptom scores and a 95% improvement over baseline in activity impairment scores, compared with corresponding values of 4% and 18% for placebo. The difference between amantadine and placebo was statistically significant. Except for one case of mild livedo reticularis and two of blurred vision in the amantadine group, side effects were generally similar for amantadine and placebo in type and frequency. This study provides new evidence of the importance of combinations of antiparkinson drugs to achieve maximum therapeutic benefit.
A considerable amount of evidence on the effectiveness of amantadine has accrued from non-controlled trials, often in patients with Parkinsonian conditions other than idiopathic Parkinson's disease. However, rigorous analysis of the six randomised controlled trials of amantadine reveals insufficient evidence of its efficacy and safety in the treatment of idiopathic Parkinson's disease.