Trihexyphenidyl is an anticholinergic medication that blocks acetylcholine, a chemical that affects movement. It's used to help with tremors in adults with Parkinson's disease (PD). It can also ease movement-related side effects caused by other medications. Trihexyphenidyl is taken by mouth, sometimes multiple times a day. It's available as tablets and an oral liquid. Common side effects of this medication include dry mouth, blurry vision, dizziness, and nausea. The brand name Artane has been discontinued, so trihexyphenidyl is generic only.
Add-on treatment for Parkinson's disease (PD)
Movement problems (extrapyramidal symptoms or EPS) caused by central nervous system medications
Trihexyphenidyl is an anticholinergic medication. It works by blocking acetylcholine, a chemical that affects different functions in the body, including movement. In doing so, trihexyphenidyl relaxes your muscles to prevent muscle spasms and tremors.
Source: DailyMed
Side effects that you should report to your care team as soon as possible:
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
Taken by mouth
Available as an oral solution for people who've a hard time swallowing tablets
Available as a lower-cost generic
Might need to take multiple times a day
Can cause more side effects in older adults
Suddenly stopping the medication can lead withdrawal symptoms
Make sure you follow the dosing instructions, especially when you first start trihexyphenidyl. Your provider will start you on a lower dose to allow your body to adjust to the medication.
If you're taking high doses of trihexyphenidyl, your provider might recommend splitting your dose into four doses. If this is the case, take three doses with meals and the fourth one before bedtime.
Trihexyphenidyl can cause you to feel dizzy and affect your ability to concentrate. Don't drive until you know how this medication affects you.
Taking trihexyphenidyl before meals can help with the dry mouth symptoms and stomach side effects. In addition to drinking water, sucking on hard candies or chewing gum can help relieve dry mouth as well.
Don't stop taking trihexyphenidyl unless instructed by your provider. Suddenly stopping the medication can lead to withdrawal symptoms, such as anxiety and worsening movement problems.
If you're taking the oral solution, store it at room temperature; don't freeze it. Make sure to use the measuring device that comes with the medication to measure your doses. Don't use kitchen or measuring spoons, since they might not be accurate.
Trihexyphenidyl can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Narrow-angle glaucoma
Trihexyphenidyl can raise your eye pressure and shouldn't be used if you have narrow-angle glaucoma. Use of trihexyphenidyl can lead to blindness in people with narrow-angle glaucoma. Let your provider know if you start to have blurry vision.
Risk factors: Not drinking enough water | Hot weather | Drinking alcohol regularly
Trihexyphenidyl makes it harder for your body to sweat and cool itself down. This can put you at risk for heat stroke, especially if you're doing manual labor outdoors when it's hot. Make sure you stay hydrated and out of the sun, especially if it's really hot out.
Suddenly stopping or lowering the dose of trihexyphenidyl too quickly can cause a condition called neuroleptic malignant syndrome (NMS). NMS can be very dangerous. Symptoms include very stiff muscles, sweating, fever, fast heartbeat, and an irregular pulse. Seek medical help right away if this happens to you.
Risk factors: High blood pressure | Heart, liver, or kidney problems
Anticholinergic medications, like trihexyphenidyl, can cause many side effects. Older adults are usually more sensitive to these effects. These side effects, such as blurry vision and dizziness, can raise the risk of serious falls. Make sure you continue to follow up with your provider so they can monitor you for long-term effects of the medication. Let them know if you start to have worsening side effects, especially if you've been taking the same dose for a while.
The recommended dosage for trihexyphenidyl tablets and trihexyphenidyl 2 mg/5 mL oral solution are the same.
Parkinson's disease: The typical starting dose is 1 mg by mouth taken on day 1. Your provider will raise your dose every few days to the target dose of 6 mg to 15 mg by mouth per day. The dose can be split up into 3 doses taken with meals.
Movement problems: The daily dose ranges from 5 mg to 15 mg by mouth per day.
Your provider might adjust your dose depending on what other medications you're taking and your response to the medication.
Add-on treatment for Parkinson's disease (PD)
Movement problems (extrapyramidal symptoms or EPS) caused by central nervous system medications
Parkinson's disease (PD)
Parkinsonism (conditions that cause people to have signs and symptoms of PD, including slowness, stiffness, shakiness, and imbalance)
Parkinson's disease (add-on medication)
Movement problems (extrapyramidal symptoms, or EPS) caused by antipsychotic medications
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