Trihexane (Oral)

Trihexyphenidyl is used by itself or with other medicines (like levodopa) to treat Parkinson's disease. It helps improve muscle control and reduce stiffness, allowing for more normal body movements as the symptoms of the disease decrease.

Trihexyphenidyl is also used to manage severe muscle reactions and other side effects from certain medicines that treat severe nausea or nervous, mental, or emotional conditions (such as haloperidol [Haldol®], loxapine [Loxitane®], prochlorperazine [Compazine®], promethazine [Phenergan®], thiothixene [Navane®]).

This medicine is available only with a prescription from your doctor.

It is important for your doctor to check your progress at regular visits so they can adjust your dose and monitor for any unwanted effects.

Before using this medicine, your doctor may want you to see an ophthalmologist (eye doctor) for an eye exam. Trihexyphenidyl may increase your risk of glaucoma. Contact your doctor immediately if you experience blurred vision or any changes in your vision while taking this medicine.

Trihexyphenidyl may cause dryness in your mouth, nose, and throat. For temporary relief of mouth dryness, you can use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth remains dry for more than 2 weeks, consult your medical doctor or dentist. Ongoing dryness in the mouth may increase the risk of dental issues, including tooth decay, gum disease, and fungal infections.

In deciding to use a medicine, you and your doctor need to think about the risks versus the benefits. Here are important things to consider for this medicine:

Allergies

Inform your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also, let your healthcare professional know if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For over-the-counter products, read the label or package ingredients carefully.

Pediatric

There is no information available about how trihexyphenidyl affects children. Safety and effectiveness have not been established.

Geriatric

There is no information available about how trihexyphenidyl affects older adults. However, older men are more likely to have prostate problems, and all older patients are more likely to have kidney, liver, or heart issues. These conditions may require caution or a dose adjustment for patients taking trihexyphenidyl.

Breast Feeding

Studies indicate that this medication may change milk production or composition. If you do not receive a different medication, you should watch for side effects in the infant and ensure they are getting enough milk.

Interactions with Medicines

Some medicines should not be used together, while others may be used together even if there could be an interaction. In those cases, your doctor may change the dose or suggest other precautions. When taking this medicine, it is especially important for your healthcare professional to know if you are taking any of the following medicines. The interactions below are significant but not all-inclusive.

Using this medicine 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.

• Potassium Citrate

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in certain cases. If both medicines are prescribed together, your doctor may change the dose or frequency of one or both medicines.

• Amantadine
• Buprenorphine
• Clozapine
• Codeine
• Glucagon
• Glycopyrrolate
• Glycopyrronium Tosylate
• Methacholine
• Metoclopramide
• Oxycodone
• Quetiapine
• Revefenacin
• Scopolamine
• Secretin Human
• Tapentadol
• Tiotropium

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both medications may be the best treatment for you. If both medicines are prescribed together, your doctor may adjust the dose or frequency of one or both.

• Betel Nut
• Chlorpromazine
• Haloperidol
• Perphenazine

Interactions with Food/Tobacco/Alcohol

Some medicines should not be taken around mealtimes or with certain foods due to possible interactions. Using alcohol or tobacco with certain medicines may also lead to interactions. Talk with your healthcare professional about using your medicine with food, alcohol, or tobacco.

Other Medical Problems

Having other medical conditions may affect how you can use this medicine. Be sure to tell your doctor if you have any other medical issues, especially:

• Bowel or stomach blockage or
• Enlarged prostate or
• Glaucoma or
• Hypertension (high blood pressure) or
• Urinary blockage—Use with caution. May worsen these conditions.

• Kidney disease or
• Liver disease—Use with caution. Effects may be stronger due to slower removal of the medicine from the body.

Along with its necessary effects, a medicine may cause some unwanted effects. Although not all of these side effects may happen, if they do, they may require medical attention.

Check with your doctor right away if any of the following side effects occur:

Rare

• Abdominal or stomach cramps or pain
• bloating
• constipation
• 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

Incidence not known

• Anxiety
• 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
• hyperventilation
• irritability
• loss of vision
• mental confusion
• nervousness
• painful urination
• restlessness
• shaking
• shortness of breath
• trouble sleeping

Some side effects may happen 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, are bothersome, or if you have any questions about them:

More common

• Dizziness
• mild nausea
• nervousness

Incidence not known

• Drowsiness
• weakness

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.

In the U.S.

• Artane
• Trihexane
• Tritane

Available Dosage Forms:

• Elixir
• Tablet

Therapeutic Class: Antiparkinsonian

Pharmacologic Class: Anticholinergic

Take this medicine 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 this medicine before or after food, although it is usually taken with meals.

Dosing

The dose of this medicine 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 this medicine. 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.

Missed Dose

If you miss a dose of this medicine, 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.

Storage

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.