Antimuscarinic Pregnancy: Safety of use in pregnancy has not been established; extensive clinical use has not given evidence that procyclidine compromises the normal course of pregnancy, but use should be considered only when the expected clinical benefit to the mother outweighs any possible risk to the developing foetus. Breast-feeding: no data are available on excretion in breast milk (section 4.6).

Procyclidine hydrochloride

Brand names: Kemadrin

Procyclidine hydrochloride is an antimuscarinic agent used for Parkinson's disease and, particularly, for drug-induced parkinsonism and acute dystonic reactions.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: All forms of parkinsonism: usually started at 2.5 mg three times a day, increasing by 2.5 to 5 mg daily at intervals of two or three days until the optimum clinical response is achieved; usual maintenance 15 mg to 30 mg procyclidine per day

Route: Oral (tablets)

Frequency: Three times a day; addition of a fourth dose before retiring has been beneficial in some patients

Max: Doses up to 60 mg daily have been well tolerated and, at the prescriber's discretion, dosing to this level may be appropriate

Optimum dosage varies considerably between patients. Neuroleptic-induced extrapyramidal symptoms: usually started at 2.5 mg three times a day, increasing by 2.5 mg daily until symptoms are relieved; the effective maintenance dose is usually 10 mg to 30 mg procyclidine per day. After 3 to 4 months of therapy for neuroleptic-induced symptoms, withdraw procyclidine and observe whether extrapyramidal symptoms recur — reintroduce if they do; periodic cessation of treatment is recommended even in patients who appear to need the drug long term. Avoid abrupt discontinuation (rebound parkinsonian symptoms); when changing from one drug to another, withdraw one in small amounts while gradually increasing the other. Younger patients and those with postencephalitic parkinsonism may need higher doses than older patients and those with arteriosclerotic parkinsonism. May be given with other antiparkinsonian drugs (other antimuscarinics, levodopa, amantadine) where control is inadequate on a single agent — dose reduction may be required. Older people may be more sensitive to anticholinergic effects and a reduced dose may be required. Paediatric: use of procyclidine in this age group is not recommended. Note: this source is the ORAL tablet SPC — no injectable (intramuscular or intravenous) posology for acute dystonic reactions is present in the fetched source; source that separately if an injectable dose is needed.

Dose adjustments

Renal

No specific information is available on use in patients with impaired renal or hepatic function; since procyclidine is metabolised in the liver and excreted via the urine, care should be exercised in renal or hepatic impairment (section 4.4).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Untreated urinary retention
Closed angle glaucoma
Gastrointestinal obstruction

Side effects

Dry mouth and constipation (common)
Blurred vision (common)
Urinary retention (common)
Dizziness, memory impairment, impaired cognition, confusion, disorientation, hallucinations, agitation, anxiety, nervousness (uncommon); psychotic disorder (rare) — older people are particularly vulnerable and effects are usually reversible on dose reduction or discontinuation
Nausea, vomiting, gingivitis (uncommon); rash (uncommon); tachycardia (frequency not known)

Interactions

Monoamine oxidase inhibitors and drugs with anticholinergic properties — such as amantadine, memantine, antihistamines, phenothiazines, tricyclic and related antidepressants, clozapine (the fetched section 4.5 text is truncated at this point — verify the complete list against the current SPC)
Neuroleptics — anticholinergics do not cause tardive dyskinesia but, given with neuroleptics, may exacerbate its symptoms or lower the threshold at which dyskinesias appear; consider adjusting neuroleptic therapy or reducing anticholinergic treatment (section 4.4)
Procyclidine given for neuroleptic-induced extrapyramidal side effects has occasionally precipitated a psychotic episode in patients with mental health conditions (section 4.4)

Clinical monograph

How it works

It blocks central muscarinic acetylcholine receptors, helping to correct the relative cholinergic excess in the basal ganglia that produces parkinsonian and dystonic symptoms.

Prescribing in practice

Its antimuscarinic effects make it hazardous in glaucoma, prostatic enlargement, urinary retention and gastrointestinal obstruction, and it should not be withdrawn abruptly.
It can impair memory and precipitate confusion, so it is used cautiously in older people and avoided where there is cognitive impairment.
It is generally ineffective against tardive dyskinesia and may worsen it, so it should not be used for that indication.

Monitoring

Monitor for antimuscarinic effects including dry mouth, blurred vision, constipation, urinary retention and confusion, particularly in older patients.

Counselling the patient

This medicine can cause dry mouth, blurred vision, constipation, or difficulty passing urine.
It may affect alertness; take care driving and do not stop it suddenly without advice.
Report any new confusion or memory problems to your team.

Evidence & guidelines

Antimuscarinics such as procyclidine are long-established for drug-induced parkinsonism and acute dystonia, with their use reflected in current prescribing references and NICE guidance.

Reference: NICE CG178; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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