amantadine hydrochloride: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
amantadine hydrochloride: clinical details
Prescribing considerations
- Confirm the product-specific licensed indication; influenza A licensing does not reflect current seasonal-influenza recommendations.
- Assess renal function before treatment and during clinically relevant changes, particularly in older adults.
- Avoid abrupt withdrawal, especially alongside antipsychotics.
- Review psychiatric history, suicidality, cardiovascular disease, glaucoma risk and previous hallucinations or confusion.
- Use the smallest practical supplied quantity where self-harm risk is present.
Contraindications and cautions
- Hypersensitivity to amantadine or product excipients
- Predisposition to convulsions
- History of gastric or duodenal ulceration
- Severe renal disease
- Pregnancy
- Untreated angle-closure glaucoma is a strong product warning because of anticholinergic activity.
Monitoring
- Renal function and clinical evidence of accumulation
- Confusion, hallucinations, delirium, suicidality and impulse-control disorders
- Peripheral oedema, orthostatic symptoms and deterioration of heart failure
- New visual symptoms or suspected corneal oedema
- Adherence and any planned interruption or withdrawal
Clinical pharmacology
Amantadine is absorbed almost completely, crosses the blood–brain barrier and undergoes little metabolism. It is eliminated predominantly unchanged in urine through renal filtration and tubular secretion; impaired renal function substantially prolongs exposure, and haemodialysis removes little amantadine.
Formulation and product differences
- Selected products include hard capsules and liquid formulations.
- Capsules contain lactose; quantities and other excipients differ by manufacturer.
- The oral solution and syrup contain sorbitol, which can cause gastrointestinal discomfort and matters in hereditary fructose intolerance.
- Liquid products contain methyl and propyl hydroxybenzoates, which may cause delayed allergic reactions.
- Check the individual SmPC and package leaflet because licensed indications differ between formulations.
amantadine hydrochloride preparations and strengths
Capsule
Route: Oral
Strengths: 100 mg
Oral solution
Route: Oral
Strengths: 50 mg/5 mL
Syrup
Route: Oral
Strengths: 50 mg/5 mL
amantadine hydrochloride interactions
Check all prescribed, over-the-counter and recreational substances before treatment.
Anticholinergic medicines
May increase confusion, hallucinations, nightmares, constipation, dry mouth and urinary problems.
Levodopa
May increase hallucinations, confusion and other central or anticholinergic effects.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.