L-dopa and carbidopa (sinemet) in the management of parkinsonism.

Parkinsonism is a degenerative disease. A weakening in the responsiveness to dopamine replacement therapy affects many patients: thus 45% fail to maintain their initial improvement after 2 years' and 50% after 3 years' medication. However, by reducing the peripheral and systemic side actions of dopamine through the selective introduction of sinemet, a decarboxylase inhibitor+ L-dopa combination, a partial amelioration of as much as 35% at 2 years, or 20% at 3 years, can be achieved. There is evidence, also, that the initial choice of anti-parkinsonian therapy may be critical to the long term prognosis.