Medically reviewed on March 25, 2018.
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
- Capsule, Extended Release
Therapeutic Class: Antiparkinsonian
Pharmacologic Class: Anticholinergic
Uses For trihexyphenidyl
Trihexyphenidyl is used alone or together with other medicines (e.g., levodopa) to treat Parkinson's disease. By improving muscle control and reducing stiffness, trihexyphenidyl allows more normal movements of the body as the disease symptoms are reduced.
Trihexyphenidyl is also used to control severe muscle reactions and other side effects from certain medicines that are used to treat severe nausea or nervous, mental, or emotional conditions (e.g., haloperidol [Haldol®], loxapine [Loxitane®], prochlorperazine [Compazine®], promethazine [Phenergan®], thiothixene [Navane®]).
trihexyphenidyl is available only with your doctor's prescription.
Before Using trihexyphenidyl
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For trihexyphenidyl, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to trihexyphenidyl or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
No information is available on the relationship of age to the effects of trihexyphenidyl in the pediatric population. Safety and efficacy have not been established.
No information is available on the relationship of age to the effects of trihexyphenidyl in geriatric patients. However, elderly men are more likely to have age-related prostate problems, and all elderly patients are more likely to have age-related kidney, liver, or heart problems. These conditions may require caution or an adjustment in the dose for patients receiving trihexyphenidyl.
Studies suggest that this medication may alter milk production or composition. If an alternative to this medication is not prescribed, you should monitor the infant for side effects and adequate milk intake.
Interactions with Medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking trihexyphenidyl, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using trihexyphenidyl with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using trihexyphenidyl with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Secretin Human
Using trihexyphenidyl with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Betel Nut
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of trihexyphenidyl. Make sure you tell your doctor if you have any other medical problems, especially:
- Bowel or stomach blockage or
- Enlarged prostate or
- Glaucoma or
- Hypertension (high blood pressure) or
- Urinary blockage—Use with caution. May make these conditions worse.
- Kidney disease or
- Liver disease—Use with caution. Effects may be increased because of slower removal of the medicine from the body.
Proper Use of trihexyphenidyl
Take trihexyphenidyl every day exactly as ordered by your doctor in order to improve your condition as much as possible. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
You may take trihexyphenidyl before or after food, although it is usually taken with meals.
The dose of trihexyphenidyl will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of trihexyphenidyl. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (elixir or tablets):
- For Parkinson's disease:
- Adults—At first, 1 milligram (mg) once a day. Your doctor may increase your dose as needed. However, the dose is usually not more than 15 mg per day, given in divided doses 3 or 4 times per day.
- Children—Use and dose must be determined by your doctor.
- For side effects caused by other medicines:
- Adults—5 to 15 milligrams (mg) per day, given in divided doses 3 or 4 times per day.
- Children—Use and dose must be determined by your doctor.
- For Parkinson's disease:
If you miss a dose of trihexyphenidyl, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions While Using trihexyphenidyl
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 trihexyphenidyl, 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 trihexyphenidyl.
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.
trihexyphenidyl Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:Rare
- Abdominal or stomach cramps or pain
- delusions of persecution, mistrust, suspiciousness, or combativeness
- excessive dryness of the mouth
- false beliefs that cannot be changed by facts
- loss of appetite
- nausea or vomiting
- seeing, hearing, or feeling things that are not there
- skin rash
- stomach pain
- swollen, painful, or tender lymph glands on the side of the face or neck
- blurred vision
- change in vision
- decrease in frequency of urination
- decrease in urine volume
- difficult urination
- difficulty in passing urine (dribbling)
- disturbed behavior
- dry mouth
- enlarged pupils
- eye pain
- fast, pounding, or irregular heartbeat or pulse
- loss of vision
- mental confusion
- painful urination
- shortness of breath
- trouble sleeping
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:More common
- mild nausea
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 2018 Truven Health Analytics, Inc. All Rights Reserved.
More about trihexyphenidyl
- Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Images
- Drug Interactions
- Support Group
- Pricing & Coupons
- En Español
- 14 Reviews – Add your own review/rating
- Drug class: anticholinergic antiparkinson agents