(BENZHEXOL)

Indications & Dose:

Parkinson’s disease (if used in combination with cocareldopa or cobeneldopa)

Adult: Maintenance 2–6 mg daily in divided doses, use not recommended because of toxicity in the elderly and the risk of aggravating dementia

Parkinsonism

Drug-induced extrapyramidal symptoms (but not tardive dyskinesia)

• BY MOUTH

Adult: 1 mg daily, then increased in steps of 2 mg every 3–5 days, adjusted according to response; maintenance 5–15 mg daily in 3–4 divided doses, not recommended for use in Parkinson’s disease because of toxicity in the elderly and the risk of aggravating dementia; maximum 20 mg per day

Elderly: Lower end of range preferable, not recommended for use in Parkinson’s disease because of toxicity in the elderly and the risk of aggravating dementia 

Contraindications:

Untreated urinary retention, closed-angle glaucoma, gastro-intestinal obstruction. 

Side Effects:

By mouth, gastro-intestinal disturbances, dizziness, blurred vision; less commonly urinary retention, tachycardia, hypersensitivity, nervousness, and with high doses in susceptible patients, mental confusion, excitement, and psychiatric disturbances which may necessitate discontinuation of treatment

Cautions:

 Cardiovascular disease, hepatic or renal impairment; avoid abrupt  dis-continuation of treatment; liable to abuse; (antimuscarinics). May affect performance of skilled tasks  (e.g. driving). 

Precautions:

 History of epilepsy, recent MI Safety not established.

Breastfeeding: Use with caution.

Old age: Use with caution. 

Interaction:

Drugs

Amantadine: Increased incidence of anticholinergic side effects which disappear on reducing the dose of trihexiphenidyl.

Digoxin: Serum levels of digoxin increased when given orally as a slow dissolution tablet.

Haloperidol: Decreased haloperidol serum concentration may result in worsening of schizophrenic symptoms; also development of tardive dyskinesia.

Levodopa: Efficacy of levodopa may be reduced. 

Warnings:

Adverse Effects:

Lactations:

Special Precautions:

Counselling:

Side Effects Or Adverse Reactions:

Patient And Carer Advice: