Trihexyphenidyl 0.4mg/ml Elixir

Trihexyphenidyl is a synthetic anticholinergic agent that acts as a muscarinic acetylcholine receptor antagonist. It exerts its therapeutic effect by blocking cholinergic impulses in the parasympathetic nervous system, thereby reducing the relative excess of cholinergic activity that is thought to be responsible for the symptoms of Parkinson's disease and drug-induced extrapyramidal disorders. It also has a direct relaxant effect on smooth muscle.

Urgent Side Effects: Seek Medical Help Right Away

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:

Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Hallucinations (seeing or hearing things that are not there)
Feeling agitated or experiencing a change in behavior
Confusion or memory problems
Difficulty urinating
Rapid heartbeat
Severe constipation or stomach pain, which may indicate a serious bowel problem
Muscle weakness
New or worsening trouble controlling body movements
Changes in vision, eye pain, or severe eye irritation
Fever
Inability to sweat during physical activity or in warm temperatures
Enlarged pupils
Neuroleptic malignant syndrome (NMS), a rare but potentially deadly condition that can occur when this medication is stopped suddenly or the dose is lowered. Symptoms of NMS include:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Changes in thinking
+ Abnormal heartbeat
+ Excessive sweating

Other Possible Side Effects

Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor:

Dizziness or drowsiness
Upset stomach or vomiting
Constipation
Headache
Dry mouth
Feeling nervous or excitable

Reporting Side Effects

This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have been diagnosed with narrow-angle glaucoma, a condition that affects the eyes.
* If you have a history of tardive dyskinesia, a severe muscle disorder.

This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. Additionally, share any health problems you have, as they may interact with this medication.

To ensure your safety, always check with your doctor before starting, stopping, or changing the dose of any medication. This will help prevent potential interactions and ensure that it is safe for you to take this medication with your other drugs and health conditions.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.

Before operating a vehicle or engaging in any activity that requires your full attention, wait until you understand how this medication affects you. It is also crucial to discuss the use of alcohol, marijuana, or other forms of cannabis, as well as prescription or over-the-counter (OTC) medications that may cause drowsiness, with your doctor beforehand.

Do not abruptly discontinue this medication without first consulting your doctor, as this may increase your risk of experiencing side effects. If it becomes necessary to stop taking this drug, your doctor will provide guidance on how to gradually taper off the medication to minimize potential side effects.

Individuals with narrow-angle glaucoma should be aware that this medication has been associated with vision loss. It is vital to consult with your doctor about this potential risk. Additionally, adhere to your doctor's recommendations for regular eye pressure and vision checks.

There is a risk of heat stroke associated with this medication, particularly in hot weather or during physical activity. Therefore, it is crucial to exercise caution and stay hydrated. If you are 60 years or older, use this medication with caution, as you may be more susceptible to side effects.

If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor. It is essential to discuss the potential benefits and risks of this medication to both you and your baby.

• Other anticholinergics (e.g., atropine, scopolamine, tricyclic antidepressants, phenothiazines, antihistamines with anticholinergic effects): Increased risk of anticholinergic side effects (dry mouth, blurred vision, urinary retention, constipation, confusion, heat stroke).
• Potassium chloride (oral solid dosage forms): Increased risk of gastrointestinal lesions due to delayed gastric emptying.

• CNS depressants (e.g., alcohol, opioids, benzodiazepines): Additive sedative effects.
• Cholinesterase inhibitors (e.g., donepezil, rivastigmine, galantamine): Antagonistic effects, may reduce efficacy of cholinesterase inhibitors.
• Metoclopramide: Antagonistic effect on GI motility.
• Digoxin: May increase digoxin levels due to delayed GI motility.

• Dry mouth
• Blurred vision
• Constipation
• Urinary hesitancy/retention
• Dizziness
• Nausea
• Nervousness
• Confusion
• Hallucinations
• Memory impairment
• Tachycardia
• Heat intolerance/reduced sweating

Category C. Use only if the potential benefit justifies the potential risk to the fetus. Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Trihexyphenidyl is excreted into breast milk. Due to potential for anticholinergic effects in the infant (e.g., sedation, dry mouth, constipation, urinary retention) and potential for decreased milk production, use is generally not recommended during breastfeeding. If used, monitor infant closely for adverse effects.

Safety and efficacy not well established in children under 3 years of age. Use in children should be approached with caution due to increased susceptibility to adverse effects, particularly CNS effects. Dosing for dystonia in children is off-label and requires careful titration.

Elderly patients are more susceptible to the anticholinergic side effects of trihexyphenidyl, particularly confusion, hallucinations, memory impairment, urinary retention, and constipation. They are also at increased risk for falls. Lower initial doses and slower titration are recommended. Avoid use in elderly patients with cognitive impairment or dementia due to exacerbation of symptoms.

• Trihexyphenidyl is particularly effective for reducing tremor and rigidity in Parkinson's disease, but less effective for bradykinesia.
• It is commonly used to manage drug-induced extrapyramidal symptoms (EPS) caused by antipsychotics, especially dystonia and akathisia.
• Start with a low dose and titrate slowly to minimize anticholinergic side effects.
• Administer with or after meals to minimize gastrointestinal upset.
• Patients should be advised about the potential for dry mouth, blurred vision, and constipation, and strategies to manage these (e.g., sugar-free candies, artificial tears, increased fiber/fluids).
• Monitor for signs of central anticholinergic syndrome, especially in elderly patients or those on concomitant anticholinergic medications.
• Abrupt discontinuation can lead to withdrawal symptoms or worsening of Parkinsonian symptoms/EPS.

• Benztropine (another anticholinergic)
• Amantadine (for Parkinson's and drug-induced EPS)
• Dopaminergic agents (e.g., levodopa/carbidopa, dopamine agonists for Parkinson's)
• Beta-blockers (e.g., propranolol for tremor)
• Benzodiazepines (e.g., lorazepam for acute dystonia/akathisia)

If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more details. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide information about the medication taken, the amount, and the time it happened.