Tremors anticholinergic drugs

Anticholinergic drugs can be effective for tremor and dystonic features in some patients but rarely show substantial benefit for bradykinesia or other disabilities. They can be used as monotherapy or in conjunction with other antiparkinsonian drugs. They differ little from each other in therapeutic potential or adverse effects. 

These drugs were developed before levodopa which has largely replaced them, probably because of a lack of modern clinical research. Actually, the adverse effects of anticholinergic drugs (confusion, memory disorders, peripheral anticholinergic effects) and the interindividual variability of their effects considerably limit their use, particularly in subjects over 65 years of age. These compounds are considered to be effective against tremor and are... 

A 45-year-old woman with a family history of essential tremor developed severe and persistent parkinsonism after taking kava extract for anxiety for 10 days. Her symptoms improved with anticholinergic drugs. 

The method used has been described by Brimblecombe and Green (1968). Essentially, mice were injected intraperitoneally with the anticholinergic drug 15 min before the intravenous injection of 100 /ig/kg oxotremorine. The animals were observed for the presence of salivation and/or tremors. An ED50 for block of salivation and of tremors... 

Tremor was observed in 30 patients (57.7%) and this mainly affected the limbs. In half the cases the tremor was evident before treatment with fluphenazine began but was made worse by the administration of the drug. Tremor was well tolerated in all but 6 patients. Akathisia occurred in 20 patients and caused malaise and insomnia in some which was relieved by hypnotics. Six patients (11.5%) developed acute dystonias, torticollis, movements of the tongue, opisthotonos and choreo-athetoid movements of the limbs which responded to treatment with anticholinergic drugs. Laboratory tests carried out during and at the conclusion of the study showed no abnormalities (17 -). 

Pharmacotherapy. The currently available treatments for PD are symptomatic, and do not alter the course of the disease. The earliest treatment that is still in limited use today, is with the anticholinergic medications, such as trihexiphenidyl or benzotropine. These drugs are useful, particularly for tremor. However, their use is often prob-lematic because of unpleasant side-effects, such as memory disturbances, blurred vision, sedation, dry mouth, or urinary retention, particularly in older patients. 

Trihexyphenidyl, an antiparkinsonian drug, possesses central and peripheral anticholinergic actions, as well as a direct relaxant effect on smooth muscle. It reduces muscle rigidity and general stiffness, and has a relatively minor effect on tremors. It is used in Parkinsonism in the form of monotherapy as well as in combination with levodopa. The most common synonyms are parkopan, parkinsan, and cyclodol. 

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