Trihexyphenidyl, Oral

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KEY POINTS

• This medicine is taken by mouth to treat and control symptoms of Parkinson's disease. It may also be used to control side effects caused by certain medicines. Take it exactly as directed.
• Keep all appointments for tests to see how this medicine affects you.
• This medicine may cause unwanted side effects. Tell your healthcare provider if you have any side effects that are serious, continue, or get worse.
• Tell all healthcare providers who treat you about all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take.

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What are other names for this medicine?

Type of medicine: anticholinergic; anti-Parkinson’s

Generic and brand names: trihexyphenidyl, oral

What is this medicine used for?

This medicine is taken by mouth to treat and control symptoms of Parkinson's disease. It may also be used to control side effects caused by certain medicines.

This medicine may be used to treat other conditions as determined by your healthcare provider.

What should my healthcare provider know before I take this medicine?

Before taking this medicine, tell your healthcare provider if you have ever had:

• An allergic reaction to any medicine
• A blockage in the intestines, Crohn's disease, or ulcerative colitis
• Glaucoma
• Heart disease or an irregular heartbeat
• Liver or kidney problems
• Mental health problems such as dementia, obsessive-compulsive disorder, or schizophrenia
• Myasthenia gravis
• Problems with alcohol abuse
• Tardive dyskinesia
• Trouble urinating or an enlarged prostate gland

Females of childbearing age: Tell your healthcare provider if you are pregnant or plan to become pregnant. It is not known whether this medicine will harm an unborn baby. Do not breast-feed while taking this medicine without your healthcare provider's approval.

How do I take it?

Check the label on the medicine for directions about your specific dose. Take this medicine exactly as your healthcare provider prescribes. Do not take more or less or take it longer than prescribed. Do not stop taking this medicine without your healthcare provider's approval.

Check with your healthcare provider before using this medicine in children under age 18.

You may take this medicine with or without food. Taking it with meals may lessen the chance the drug will upset your stomach.

If you have the liquid form of this medicine, use the measuring spoon, cup, dropper, or oral syringe that comes with the medicine, or ask your pharmacist for one. Do not use a kitchen spoon because the dose may not be correct.

What if I miss a dose?

If you miss a dose, take it as soon as you remember unless it is almost time for the next scheduled dose. In that case, skip the missed dose and take the next one as directed. Do not take double doses. If you are not sure of what to do if you miss a dose, or if you miss more than one dose, contact your healthcare provider.

What if I overdose?

If you or anyone else has intentionally taken too much of this medicine, call 911 or go to the emergency room right away. If you pass out, have seizures, weakness or confusion, or have trouble breathing, call 911. If you think that you or anyone else may have taken too much of this medicine, call the poison control center. Do this even if there are no signs of discomfort or poisoning. The poison control center number is 800-222-1222.

Symptoms of an acute overdose may include: large pupils, hot dry skin, flushed face, fever, loss of balance, dry mouth, fast or irregular heartbeat, anxiety, hallucinations, confusion, restlessness, fainting, seizures, coma.

What should I watch out for?

This medicine increases the effects of alcohol and other drugs that slow down your nervous system. Do not drink alcohol or take other medicines unless your healthcare provider approves.

While you are taking this medicine you may become more sensitive to heat and may sweat less. Exercise with caution, especially in hot weather. You may need to drink extra liquids. Discuss this with your healthcare provider.

This medicine may make you feel drowsy or dizzy or may cause blurred vision. Do not drive or operate machinery unless you are fully alert. You may feel dizzy or faint when you get up quickly after sitting or lying down. Getting up slowly may help.

Your eyes may be more sensitive to light. Wear sunglasses when outdoors and avoid bright lights. Also, your healthcare provider may want you to have your eyes checked regularly while you are taking this medicine.

This medicine may cause a dry mouth. Sucking on hard, sugar-free candy or chewing sugar-free gun may help.

This medicine may make you constipated. You may need a laxative or stool softener while taking this medicine. Talk with healthcare provider or pharmacist about this.

Adults over the age of 60 may be at greater risk for side effects. Talk with your healthcare provider about this.

Contact your healthcare provider if your condition does not improve in a few days or if it gets worse.

If you need emergency care, surgery, lab tests, or dental work, tell the healthcare provider or dentist you are taking this medicine.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your healthcare provider if you have any side effects that continue or get worse.

Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help.): Allergic reaction (hives; itching; rash; trouble breathing; chest pain or tightness in your chest; swelling of your lips, tongue, and throat).

Serious (Report these to your healthcare provider right away.): Fast or irregular heartbeat, chest pain, hallucinations (seeing or hearing things that are not there), memory loss, trouble urinating, fever, severe vomiting, confusion, eye pain, sudden vision problems, trouble swallowing or speaking, severe muscle weakness or stiffness.

Other: Dry mouth, drowsiness, dizziness, nervousness, constipation, headache, nausea, vomiting, sensitivity to light, rash, itching, trouble sleeping.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your healthcare provider if you are taking:

• Alzheimer’s disease medicines such as donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon)
• Antianxiety medicines such as alprazolam (Xanax), clonazepam (Klonopin), clorazepate (Gen-Xene, Tranxene), diazepam (Valium), lorazepam (Ativan), and oxazepam
• Antidepressants such as amitriptyline, citalopram (Celexa), clomipramine, desipramine (Norpramin), desvenlafaxine (Pristiq), duloxetine (Cymbalta), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), imipramine (Tofranil), nefazodone, nortriptyline (Pamelor), sertraline (Zoloft), trazodone, and venlafaxine (Effexor)
• Antihistamines such as chlorpheniramine (Chlor-Trimeton), diphenhydramine (Benadryl), hydroxyzine (Vistaril), and meclizine (Dramamine)
• Antipsychotic medicines such as aripiprazole (Abilify), asenapine (Saphris), chlorpromazine, clozapine (Clozaril, FazaClo), fluphenazine, haloperidol (Haldol), iloperidone (Fanapt), lurasidone (Latuda), olanzapine (Zyprexa), paliperidone (Invega), perphenazine, pimozide (Orap), quetiapine (Seroquel), risperidone (Risperdal), thioridazine, trifluoperazine, and ziprasidone (Geodon)
• Antiseizure medicines such as carbamazepine (Carbatrol, Epitol, Equetro, Tegretol), felbamate (Felbatol), gabapentin (Neurontin), lamotrigine (Lamictal), levetiracetam (Keppra), oxcarbazepine (Trileptal), phenytoin (Dilantin, Phenytek), primidone (Mysoline), tiagabine (Gabitril), topiramate (Qudexy, Topamax, Trokendi), and valproic acid (Depacon, Depakene, Depakote)
• Barbiturates such as butabarbital (Butisol), pentobarbital (Nembutal), phenobarbital, and secobarbital (Seconal)
• Bupropion (Aplenzin, Forfivo, Wellbutrin, Buproban, Zyban)
• Doxepin (Silenor)
• Muscle relaxants such as baclofen (Gablofen, Lioresal), carisoprodol (Soma), cyclobenzaprine (Amrix), dantrolene (Dantrium), methocarbamol (Robaxin), and tizanidine (Zanaflex)
• Natural remedies such as gotu kola, kava, St. John's wort, and valerian
• Nausea medicines such as prochlorperazine (Compro) and promethazine
• Other anticholinergic medicines such as belladonna, benztropine (Cogentin), dicyclomine (Bentyl), hyoscyamine (HyoMax, Levbid, Levsin), ipratropium (Atrovent), methscopolamine (Pamine), propantheline, and tiotropium (Spiriva), and trihexyphenidyl
• Pain medicines such as codeine, fentanyl (Abstral, Actiq, Duragesic, Fentora, Sublimaze), hydrocodone (Hysingla, Zohydro), hydrocodone/acetaminophen (Norco, Vicodin), hydromorphone (Dilaudid, Exalgo), meperidine (Demerol), methadone (Dolophine, Methadose), morphine (Kadian, MS Contin), oxycodone (OxyContin, Roxicodone), tapentadol (Nucynta), and tramadol (ConZip, Ultram)
• Paroxetine (Brisdelle, Paxil, Pexeva)
• Potassium supplements or salt substitutes that contain potassium
• Pramlintide (Symlin)
• Sleeping pills such as eszopiclone (Lunesta), flurazepam, temazepam (Restoril), triazolam (Halcion), zaleplon (Sonata), and zolpidem (Ambien, Edluar, Intermezzo)

If you are not sure if your medicines might interact, ask your pharmacist or healthcare provider. Keep a list of all your medicines with you. List all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take. Be sure that you tell all healthcare providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.

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This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your healthcare provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.