What is Trihexyphenidyl: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Trihexyphenidyl overview

BRAND NAMES:

Generic Names:

  • Trihexyphenidyl Hcl

Uses:

  • Treats symptoms of Parkinson's disease or side effects of other drugs.

Therapeutic Classes:

  • Antiparkinsonian

Forms:

  • Tablet, Long Acting Capsule, Liquid

How it’s taken:

  • By mouth

What is Trihexyphenidyl used for?

What form(s) does Trihexyphenidyl come in

  • Tablet

  • Long Acting Capsule

  • Liquid

What are common Trihexyphenidyl doses?

  • Tablet 2MG

  • Tablet 5MG

  • Bottle 473ML of 0.4MG/ML

Common Trihexyphenidyl prescriptions

  • Trihexyphenidyl HCl
    100 tablets bottle

  • Trihexyphenidyl HCl
    473ml of 0.4mg/ml bottle

  • Trihexyphenidyl HCl
    2mg tablet

  • Trihexyphenidyl HCl
    5mg tablet

How to take Trihexyphenidyl

  • Your doctor will tell you how much to take and how often.

  • This medicine may be taken before or after meals. Swallow whole. Do not crush, chew, or open the capsules before swallowing.

  • Measure the oral liquid with a measuring spoon or medicine cup.

  • Your doctor will tell you how much to take and how often.

  • This medicine may be taken before or after meals. Swallow whole. Do not crush, chew, or open the capsules before swallowing.

  • Measure the oral liquid with a measuring spoon or medicine cup.

What to do if you miss a dose of Trihexyphenidyl

  • Take the missed dose as soon as possible.

  • If it is almost time for your next regular dose, wait until then to take your medicine, and skip the missed dose.

  • You should not use two doses at the same time.

Trihexyphenidyl contraindications

  • You should not use this medicine if you have had an allergic reaction to trihexyphenidyl.

Trihexyphenidyl warnings

  • Talk with your doctor before taking this medicine if you have glaucoma, an enlarged prostate, bowel or stomach problems, fast or irregular heartbeat, liver, heart, or kidney disease, or any other medical problems.

  • This medicine may cause drowsiness. Be careful if you are driving, using machinery, or doing other dangerous jobs.

  • This medicine may make you sweat less and cause your body to get too hot. Be careful during hot weather, while you are exercising, or if using a sauna or whirlpool.

  • Pain when urinating or decrease in amount of urine

  • Fast or irregular heartbeat

  • Eye pain

Trihexyphenidyl interactions

  • Avoid drinking alcohol while taking this medicine.

  • Make sure your doctor knows if you are taking any other medicines that may make you sleepy such as sleeping pills, cold and allergy medicine, muscle relaxants, tranquilizers, or narcotic pain killers.

  • This medicine may make you sweat less and cause your body to get too hot. Be careful during hot weather, while you are exercising, or if using a sauna or whirlpool.

Trihexyphenidyl side effects

Serious Side Effects

  • Eye pain

  • Confusion or agitation

  • Hearing or seeing or unusual things

  • Severe stomach pain or constipation

  • Pain when urinating or decrease in amount of urine

  • Fast or irregular heartbeat

Less Serious Side Effects

  • Blurred vision

  • Dry mouth

  • Nervousness

  • Nausea

  • Dizziness or drowsiness