Trihexyphenidyl

Antiparkinsonism Preps · Anticholinergic

Indications

Parkinsonism. Drug induced extra-pyramidal reactions.

Dosage

Adults: Parkinsonism: 1 mg first day, 2 mg 2nd day, then increase 2 mg daily every 3-5 days. Maintenance, usually 5-15 mg daily. Drug induced extra-pyramidal reactions: Initial: 1 mg, increase until achieve control. Usual: 5-15 mg/day. Children: Not recommended.

Adverse Effects

Anticholinergic effects. Confusion, agitation, delusions and euphoria in high doses.

Risk Factor (Pregnancy/Lactation)

Pregnancy: Risk cannot be ruled out. Lactation: Caution advised or effect undetermined. Precautions: Narrow angle glaucoma. Gl obstruction. Prostatic hypertrophy. Cardiac, hepatic or renal disorders, hypertension, tardive dyskinesia, myasthenia gravis. Withdraw treatment slowly. Elderly.

Interactions

Phenothiazines, antihistamines and antidepressants, MAOIs, clozapine, nefopam, TCADs, disopyramide, amantadine, metoclopramide, domperidone, levodopa, parasympathomimetics.

Advice to Patient

Take with meals. If you have dry mouth, take before meals. If you have nausea or drools, take after meals. Take at the same time each day. Do not chew or break extended release capsules. Use calibrated device to measure elixir. Contact prescriber if there is difficulty in breathing, chest pain, palpitations, unrelieved constipation, painful or difficult urination, loss of memory, nervousness, hallucinations, skin rash, increased muscle spasm, rigidity or if there is worsening of condition. Do not take prescription medications, OTC sedatives or CNS depressants without consulting prescriber. For parkinsonism, do not stop taking medication abruptly, gradually lower the dose and then stop. Avoid alcohol during therapy. Take sufficient amount of fluids (2-3 litres per day) to maintain hydration, unless restricted by the prescriber. Empty bladder before taking medication. Limit exercise…

Pharmacokinetics

Onset: 1 hr. Duration: 6-12 hrs. Absorption: Rapidly absorbed. Half-life elimination: 3.3 -4.1 hrs. Time to peak, plasma: 1.3 hrs. Excretion: Urine and bile.

Unlicensed Use

Children: Dystonia: 3 mth-18 yr, initially 1-2 mg daily in 1-2 divided doses, increased every 3-7 days by 1 mg daily; adjusted according to response and side-effects, max 2 mg/kg daily.

Compiled by Healify Pharmacy from published drug references. How we compile it →

Always consult a pharmacist or doctor.