Idiopathic ParkinsonismFor initial therapy for symptoms of idiopathic parkinsonism, 1 mg tablet of trihexyphenidyl is given on the first day. This dose could then increase by 2 mg accretions at intervals of around four days until a total dose of 6 to 10 mg is administered daily to the patient. The final daily dose is determined by the clinician to what is deemed the optimal dosage for symptom control. Most patients show significant symptom improvement on 6 to 10 mg daily. Still, some, especially those of the postencephalitic sub-group, could require daily doses of around 12 to 15 mg for symptom management.