Trihexyphenidyl | Side Effects, Dosage, Uses & More
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Generic Name:

trihexyphenidyl, Oral tablet

All Brands

  • Artane (Discontinued)
A discontinued drug is a drug that has been taken off the market due to safety issues, shortage of raw materials, or low market demand.
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Highlights for trihexyphenidyl

Oral tablet
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Trihexyphenidyl is used to treat all forms of parkinsonism, including Parkinson’s disease.

2

This drug is also used to treat severe movement side effects caused by antipsychotic drugs (drug-induced movement disorders).

3

Your healthcare provider should always start you on a low dose of trihexyphenidyl and slowly increase your dose as needed, especially if you are aged 60 years old or older. Increasing the doses slowly will lower the risk of side effects.

4

Your healthcare provider should always start you on a low dose of trihexyphenidyl and slowly increase your dose as needed, especially if you are aged 60 years old or older. Increasing the doses slowly will lower the risk of side effects.

5

Some of the more common side effects from using trihexyphenidyl include dry mouth, blurred vision, dizziness, nausea, nervousness, constipation, drowsiness, and trouble urinating.

IMPORTANT INFORMATION

Heat stroke

Taking trihexyphenidyl can put you at risk of heat stroke. It makes you sweat less, which can affect your body’s ability to cool itself. This increases your risk of hyperthermia (very high body temperature). If your body gets too hot and cannot cool down, you could have heat stroke.

Neuroleptic malignant syndrome

Suddenly stopping or reducing your dose of trihexyphenidyl too quickly increases your risk of this rare but life-threatening condition. If you have any of the following symptoms while taking this drug, you should call your doctor immediately: high fever, muscle stiffness, slowed thoughts, changes in blood pressure, fast heart rate, and sweating.

Drug features

Trihexyphenidyl is a prescription drug. It’s available as an oral solution and an oral tablet. It’s only available as a generic drug.

Trihexyphenidyl may be used as part of a combination therapy. This means you may need to take it with other medications.

Why it's used

Trihexyphenidyl is used to control parkinsonism, including Parkinson’s disease and drug-induced movement disorders caused by taking antipsychotic drugs.

How it works

Trihexyphenidyl belongs to a class of drugs called antispasmodics. A class of drugs is a group of medications that work in a similar way.

More Details

How it works

Trihexyphenidyl belongs to a class of drugs called antispasmodics. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Trihexyphenidyl works by blocking a certain part of your nervous system that regulates body movements. It helps relax certain muscles and make it easier to move freely.

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trihexyphenidyl Side Effects

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More Common Side Effects

  • Some of the more common side effects that can occur with use of trihexyphenidyl include:

    • dry mouth
    • blurred vision
    • dizziness
    • nausea
    • nervousness
    • constipation
    • drowsiness
    • trouble urinating
  • In addition to the side effects listed above, the following have been reported in children who have used this drug:

    • forgetfulness
    • weight loss
    • restlessness
    • trouble sleeping
    • muscle spasms
    • involuntary body movements

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Irregular heartbeats

  • Hallucinations

  • Paranoia

  • Glaucoma. Symptoms can include:

    • eye pain
    • blurred vision
    • sudden or gradual loss of vision
    • tunnel vision
    • rainbow-colored circles around bright lights
  • Intestinal problems. Symptoms can include:

    • bloating
    • stomach pain
    • severe constipation
    • nausea
    • vomiting
    • loss of appetite
  • Heat stroke or trouble sweating or both. Symptoms can include:

    • inability to sweat
    • tiredness
    • fainting
    • dizziness
    • muscle or stomach cramps
    • nausea
    • vomiting
    • diarrhea
    • confusion
    • fever
  • Neuroleptic malignant syndrome (NMS). Symptoms include:

    • fever
    • rigid muscles
    • involuntary movements
    • altered consciousness
    • mental status changes
    • fast pulse
    • fast and shallow breathing
    • high or low blood pressure
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Trihexyphenidyl may cause drowsiness.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
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trihexyphenidyl May Interact with Other Medications

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Trihexyphenidyl can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Alcohol interaction

If you drink alcohol, talk to your doctor. The use of drinks that contain alcohol can increase your risk of sedation from trihexyphenidyl.

Medications that might interact with this drug

Other drugs used for Parkinson’s disease

Taking levodopa and trihexyphenidyl together may cause an increase in drug-induced involuntary movement. When taken together, the doses of one or the other or both of these drugs may need to be reduced.

Depression drugs

Certain depression drugs can increase the risk of side effects such as dry mouth, trouble urinating, bloating, less sweat, and increased body temperature.

Some of these drugs include:

  • isocarboxazid
  • phenelzine
  • tranylcypromine
  • amitriptyline
  • clomipramine
  • desipramine
  • nortriptyline

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

People with open-angle glaucoma

You should not use trihexyphenidyl if you have open angle glaucoma because it may cause blindness. Your doctor should do an eye exam before starting you on this drug to make sure your eye sight is okay.

People with liver disease

If you have liver disease, your body may not be able to process this drug well. This can cause an increase in the levels of this drug in your body. This can increase your risk of side effects.

People with heart disease

If you have heart disease, you may be at an increased risk for chest pain (angina), or a fast heart rate (tachycardia). Your doctor may want to monitor you more closely for side effects and start you on a lowered dose to see how you respond.

People with kidney disease

If you have kidney problems or a history of kidney disease, you may not be able to clear this drug from your body well. This may increase the levels of this drug in your body and cause more side effects. Your doctor may want to monitor you more closely for side effects if you have kidney disease.

People with high blood pressure

If you have high blood pressure, you may be at an increased risk for chest pain (angina), a heart attack, or a fast heart rate (tachycardia). Your doctor may want to monitor you more closely for side effects and start you on a lower dose to see how you respond.

People with arteriosclerosis

If you have arteriosclerosis (hardening of the walls of your arteries), your sensitivity to this drug may be increased. This can cause mental confusion, irritability, behavior changes, nausea, and vomiting. To avoid these symptoms, your doctor may want to start you at a small dose and slowly increase your dose.

Pregnant women

Trihexyphenidyl is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should be used only if the potential benefit justifies the potential risk to the fetus.

Women who are breast-feeding

Trihexyphenidyl may pass into breast milk and may cause side effects in a child who is breast-fed. Trihexyphenidyl may also lower the amount of milk allowed to the baby.

Talk to your doctor if you breast-feed your baby. You may need to decide whether to stop breast-feeding or stop taking this medication.

For seniors

If you are older than 60 years, you may be more sensitive to the effects of drugs like trihexyphenidyl. Trihexyphenidyl has been shown to cause more confusion and memory loss in older people. Your doctor may want to start on a low dose and watch for side effects.

For children

This drug should not be used in people younger than 18 years.

Allergies

Trihexyphenidyl can cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of mouth, lips and throat
  • hives
  • rash

Call 9-1-1 or go to the nearest emergency room if you develop these symptoms.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

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How to Take trihexyphenidyl (Dosage)

Oral tablet

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Parkinsonism

Generic: trihexyphenidyl

Form: Oral tablet
Strengths: 2 mg, 5 mg
Form: Oral solution
Strengths: 2 mg/5 mL
Adult dosage (ages 18–59 years)
  • The typical starting dose is 1 mg per day.
  • Your doctor may increase your dose by 2 mg every 3–5 days, until you are taking 6–10 mg per day.
  • If your parkinsonism was caused by a viral infection, you may need a dose of 12–15 mg per day.
Child dosage (ages 0–17 years)

It has not been confirmed that trihexyphenidyl is safe and effective for use in people younger than 18 years.

Senior dosage (ages 65 years and older)

If you are older than 60 years, you may be more sensitive to the effects of trihexyphenidyl. It has been shown to cause more confusion and memory loss in older people. Your doctor may start you on a low dose and watch for side effects.

 Warnings

Do not stop taking trihexyphenidyl abruptly. You can have a quick return of your symptoms and possibly develop a life-threatening condition.

Drug-induced movement disorders

Generic: trihexyphenidyl

Form: Oral tablet
Strengths: 2 mg, 5 mg
Form: Oral solution
Strengths: 2 mg/5 mL
Adult dosage (ages 18–59 years)
 
  • The typical starting dose is 1 mg per day. Your doctor may increase the dose every few hours until your symptoms disappear.
  • This may range between 5 mg and 15 mg per day. It will be determined by how well your symptoms are controlled.
  • You doctor may be able to control your symptoms better if the medication causing the EPS symptoms is reduced.
Child dosage (ages 0–17 years)

It has not been confirmed that trihexyphenidyl is safe and effective for use in people younger than 18 years.

Senior dosage (ages 65 years and older)

If you are older than 60 years, you may be more sensitive to the effects of trihexyphenidyl. It has been shown to cause more confusion and memory loss in older people. Your doctor may start you on a low dose and watch for side effects.

 Warnings

Do not stop taking trihexyphenidyl abruptly. You can have a quick return of your symptoms and possibly develop a life-threatening condition.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice

Trihexyphenidyl comes with risks if you don’t take it as prescribed.

If you stop taking the drug or don’t take it at all

Do not stop taking trihexyphenidyl abruptly. You can have a quick return of your symptoms and possibly develop a life-threatening condition. This condition is called neuroleptic malignant syndrome. If you don’t take this drug at all, your symptoms will continue or worsen.

If you miss doses or don’t take the drug on schedule

If you miss several doses or don’t take this medication on the schedule recommended by your doctor, your symptoms can return quickly.

If you take too much

You could have dangerous levels of the drug in your body. If you think you’ve taken too much of the drug, act right away. Call your doctor or local poison control center, or go to the nearest emergency room if you have dilated pupils, dry skin, fever, fast heart rate, trouble urinating, bloating, bad breath, confusion or hallucinations.

What to do if you miss a dose

Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working

Your symptoms of involuntary movement should go away when you are taking the proper dose of Trihexyphenidyl.

This drug is used for both long-term and short-term treatment.

It is used as long-term treatment for Parkinson’s disease. It may be used for both long-term and short-term treatment for other forms of parkinsonism or for drug-induced movement disorders.

Taking it with food may help to reduce upset stomach

You may wish to divide your daily dose into thirds and take each third with a meal. If your dose is more than 10 mg per day, you can divide it into fourths. You can take three of the fourths with your meals and the last fourth at bedtime.

Store trihexyphenidyl at room temperature

  • Keep it from 59°F to 86°F (15°C to 30°C). Keep it away from high temperatures.
  • Do not store this medication in moist or damp areas, such as bathrooms.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

Your doctor will check to make sure your symptoms don’t return and your vision isn’t changing. Your doctor may also run tests to check the function of your liver and kidneys.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

What does the pill look like?

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How Much Does trihexyphenidyl Cost?

Oral tablet

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Lowest price for trihexyphenidyl

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These prices represent the lowest priced national pharmacies for trihexyphenidyl on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on November 4, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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