After oral administration, the onset of action occurs within 1 hour, peak effects last 2 to 3 hours and the duration of action is 6 to 12 hours. The treatment of all forms of Parkinsonism as well as in the prevention or control of extrapyramidal disorders due to CNS drugs such as reserpine and the phenothiazines. Contraindications Patients hypersensitive to trihexyphenidyl should not be given the drug. Warnings Trihexyphenidyl should be used with caution in patients with glaucoma, obstructive disease of the gastrointestinal or genitourinary tracts, and in elderly males with possible prostatic hypertrophy. Trihexyphenidyl may cause anhidrosis.
Precautions Use extra care to reduce overheating during hot weather or exercise.
Closely observe patients with cardiac, liver, kidney or hypertensive disorders. Patients undergoing prolonged therapy should be subjected to careful periodic review to avoid unhealthy reactions. This includes medicine to treat mood disorders. Inform your doctor of any other medical conditions, allergies, pregnancy, or breast-feeding. If you notice other effects not listed above, contact your doctor, nurse, or pharmacist.