To the Editor.—
"Drug Therapy of Parkinsonism" by Yahr and Duvoisin1 and the subsequent discussion of "Treatment of Parkinsonism" by Young2 illustrate some of the chemotherapeutic paradoxes indigenous to the treatment of this disease spectrum.
Recognized for its predictive value relative to the subsequent use of levodopa (208:1168, 1969), the mechanism of action of amantadine is less understood than that of levodopa. Schwab et al estimate that amantadine "may function by decreasing inactivation of dopamine by blocking its presynaptic uptake and thereby prolonging its effective half-life following synaptic release" (222:792, 1972). Clinically, they also recognize that "the beneficial effect of amantadine occurs rapidly (within the first 24 hours) and usually follows the introduction of the first capsule."
In our practice, amantadine has been used since 1969 and certain features are outstanding when the benefits and side effects of this drug are compared with levodopa. While confusion and disorientation
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