Trihexyphenidyl, an anticholinergic, is used to against the side effects of certain psychiatric drugs (antipsychotics such as chlorpromazine/haloperidol) that treats Parkinson’s disease or involuntary movements. It helps decrease muscle stiffness, sweating, and the production of saliva, and helps improve walking ability in people with Parkinson’s disease. It is not helpful in treating movement problems caused by tardive dyskinesia and may worsen them.
How to use trihexyphenidyl
Take this medication by mouth, usually 3 to 4 times a day with meals and at bedtime, or as directed by your doctor. Your doctor may start you at a low dose and increase your dose slowly to find the best dose for you. The dosage is based on your medical condition, age, and response to therapy.
If you are using the liquid form of this medication, measure your dose with a special measuring spoon or device. Do not use a household spoon because it may not provide the correct dose.
Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same times each day.
Take this medication at least 1 hour before antacids containing magnesium, aluminum, or calcium. Allow at least 1-2 hours between doses of trihexyphenidyl and certain drugs for diarrhea (adsorbent antidiarrheals such as kaolin, pectin, attapulgite). Take this medication at least 2 hours after ketoconazole. Antacids and some drugs for diarrhea may prevent the full absorption of trihexyphenidyl, and this product may prevent the complete absorption of ketoconazole when these products are taken together.
If you are taking this medication for side effects from another medication, your doctor may instruct you to take it on a regular schedule or only as needed. If you are taking this medication for Parkinson’s disease, your doctor may change the dose of your other medications (e.g., levodopa). Follow your doctor’s instructions closely.
Rarely, abnormal drug-seeking behavior (addiction) is possible with this medication. Do not increase your dose, take it more frequently, or take it for a longer time than prescribed. Properly stop the medication when so directed. Some conditions may become worse when the drug is abruptly stopped. Your dose may need to be gradually decreased.
When used for an extended period, this medication may not work as well and may require different dosing. Talk with your doctor if this medication stops working well. Inform your doctor if your condition persists or worsens.