AMANTAMED

What it is

AMANTAMED is amantadine hydrochloride supplied as 100 mg capsules. Each capsule is a size 4 plain hard gelatin capsule with brownish-red coloured cap and body, marked with the number 100 in black ink.

Approved indications

— Idiopathic Parkinson's disease. — Post-encephalitic parkinsonism. — Symptomatic parkinsonism (for example following CNS injury from carbon monoxide poisoning). — Arteriosclerotic parkinsonism. — Drug-induced extrapyramidal reactions. — Prophylaxis of respiratory tract illness caused by influenza Type A in non-immunised individuals (including children) for whom influenza may have serious consequences (for example persons with chronic respiratory disease or diabetes mellitus).

Dosing overview

**Parkinson's disease** Adults to 65 years: when used alone, 100 mg daily for the first week of treatment, increasing in the second week to 100 mg twice daily. The dose can be titrated against signs and symptoms. Adults over 65 years: the recommended dose is 100 mg daily. **Drug-induced extrapyramidal reactions** Adults: the usual dose of amantadine hydrochloride is 100 mg twice daily. Occasionally, a patient may require 100 mg three times daily in order to obtain an optimal response. **Influenza Type A prophylaxis** Children aged 5–9 years: 100 mg once daily. Children and adults aged 10–65 years: 100 mg twice daily. Adults over 65 years: 100 mg daily.

Key safety warnings

Medical supervision during treatment with AMANTAMED is essential. The margin between the therapeutically effective dose and that producing toxic manifestations may be only 100 to 200 mg per day, and the usual daily dose should not be exceeded. Patients with pre-existing seizure disorders have been reported to develop an increased frequency of major motor seizures during amantadine ingestion. A reduction in dosage may minimise this risk, and these patients should be closely monitored. Patients with confusional, hallucinatory or psychotic states should receive AMANTAMED with caution as an increase in confusion, hallucinations, and nightmares may occur in patients with underlying psychiatric disorders. Because some patients have attempted suicide by using an overdose of amantadine, prescriptions should be written for the smallest quantity consistent with good patient management. Abrupt discontinuation of anti-parkinsonian drugs, including amantadine hydrochloride, may result in worsening of the symptoms of Parkinson's disease or in symptoms resembling neuroleptic malignant syndrome (NMS), catatonia as well as in cognitive manifestations (for example confusion, disorientation, worsening of mental status, delirium). Treatment with amantadine should not be stopped abruptly.

Contraindications

AMANTAMED is contraindicated in pregnancy and lactation, and in patients with hypersensitivity to amantadine or to any of the excipients in AMANTAMED.

PBS listing

AMANTAMED capsules containing amantadine hydrochloride 100 mg are listed on the PBS with a restriction type of restricted, and an ex-manufacturer price of A$19.62.

Regulatory history

AMANTAMED (amantadine hydrochloride 100 mg capsule) was first registered on the Australian Register of Therapeutic Goods on 18 September 2023.