Health Guide

Trihexyphenidyl hydrochloride (By mouth)

Trihexyphenidyl Hydrochloride (trye-hex-ee-FEN-i-dil hye-droe-KLOR-ide)

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

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

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

How to Use This Medicine:

Tablet, Long Acting Capsule, Liquid

  • 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.

If a dose is missed:

  • 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.

How to Store and Dispose of This Medicine:

  • Store at room temperature, away from heat, moisture, and direct light. Do not freeze the oral liquid.
  • Keep all medicine out of the reach of children.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • 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.

Warnings While Using This Medicine:

  • 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.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • 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
  • Eye pain

If you notice these less serious side effects, talk with your doctor:

  • Dry mouth
  • Dizziness or drowsiness
  • Nausea
  • Nervousness
  • Blurred vision

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 7/4/2018
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