It is important that your doctor check your progress at regular visits to allow changes in your dose and to check for any unwanted effects.
Before using this medicine, your doctor may want you to have your eyes checked by an ophthalmologist (eye doctor). Trihexyphenidyl may increase your risk of having glaucoma. Check with your doctor right away if you have blurred vision or any change in vision while taking this medicine.
Trihexyphenidyl may cause dryness of the mouth, nose, and throat. For temporary relief of mouth dryness, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.