Abstract

In Parkinson’s disease there is an imbalance between the function of the cholinergic and dopaminergic neurones in the extrapyramidal system. It is improved by drugs which antagonise cholinergic activity (anticholinergics) or stimulate dopaminergic activity (levodopa). Levodopa, when tolerated, is the most effective treatment for Parkinsonism,^{1 2} but anticholinergic drugs play an important part, either alone or with levodopa, or amantadine (Symmetrel - Geigy).¹ In Parkinsonism induced by phenothiazines, levodopa is usually ineffective,³ and anticholinergics are the drugs of choice. The dose of anticholinergic drug is limited by unwanted effects; usually these are due to peripheral actions on the parasympathetic system (e.g. dry mouth, blurred vision, constipation) but central effects such as mental confusion may be important. A new drug, with which some of these effects are claimed to be less, is benapryzine (Brizin - Beecham) which has similarities to benzhexol (Artane - Lederle; and other brands).