Trihexyphenidyl - Oral

Trihexyphenidyl is used on its own or together with other medicines to treat Parkinson's disease. Parkinson's disease is a disorder that affects the movement of a person, causing symptoms such as tremors, muscle stiffness, slowed movement, and impaired balance or walking.

This medicine may be used to treat other conditions as decided by your doctor.

Take Trihexyphenidyl exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

You may take this medicine with or without food. However, you may take this medicine before a meal if you experience excessive dry mouth, or after a meal if excessive salivation occurs. Try to take it at the same time each day.

Trihexyphenidyl is available as a tablet and oral solution.

If you are taking the oral solution, use the measuring spoon or cup provided to measure your dose.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on the type and severity of your condition and your response to the medication.

Do not stop taking Trihexyphenidyl suddenly as it may worsen your condition. Your doctor will gradually reduce the dose before stopping it completely. Follow your doctor's instructions carefully.

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.

Alert your doctor if you have increased pressure in the eye as Trihexyphenidyl may not be suitable for you.

Inform your doctor if you have the following conditions:

• heart disease or blood vessel problems e.g. high blood pressure
• prostate enlargement
• urinary retention (inability to completely empty the bladder when urinating)
• blocked stomach or bowel
• myasthenia gravis (muscle weakness disorder)
• kidney disease
• liver disease

Let your doctor know if you are pregnant or breastfeeding.

Be sure to check with your doctor or pharmacist before giving Trihexyphenidyl to the elderly. Elderly people may be more sensitive to the side effects.

This medicine may reduce sweating and may make your body temperature rise. Discuss with your doctor if you frequently need to exercise, participate in any activity, or work in a hot environment.

Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.

For as long as you are taking this medicine, you may need to have your eyes checked regularly. Your doctor will advise you about how often you need to have this test.

Trihexyphenidyl may cause dizziness or blurred vision. If affected, do not drive or take part in any activity in which you need to be alert or need to see clearly.

Other side effects include any of the following: headache, nausea, vomiting, dry mouth, constipation, difficulty sleeping, and nervousness.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:

• severe headache, fever, confusion, muscle stiffness or cramps, change in thinking, abnormal or fast heartbeat, excessive sweating
• reduced sweating during activities or in warm temperatures
• hallucinations (seeing, hearing or feeling things that are not existent)
• difficulty in passing urine
• difficulty controlling body movements that are new or worse
• changes in eyesight, painful increased pressure in the eye

Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.

Inform your doctor and pharmacist if you are taking any of these medicines:

• other medicines for Parkinson's disease e.g. levodopa, amantadine
• medicines to treat depression e.g. phenelzine, isocarboxazid, amitriptyline
• medicines for nausea or vomiting e.g. metoclopramide, domperidone
• medicines for mood disorders e.g. chlorpromazine, clozapine
• medicines for urinary retention e.g. bethanechol
• strong painkillers
• disopyramide (medicine for irregular heartbeat)

This list does not include all medicines that may interact with Trihexyphenidyl.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements, and medicines that you buy without a prescription.

Avoid alcohol. Alcohol intake may worsen the dizziness caused by Trihexyphenidyl.

Store in a cool, dry place away from the reach of children.

Medicines must not be used past the expiry date.