Amantadine Other names: 1-aminoadamantane Amantadine Amantadine hydrochloride

Concurrent administration may increase confusion, hallucinations, nightmares, gastro-intestinal disturbances, or other atropine-like side effects.

Psychotic reactions have been observed in patients receiving amantadine and levodopa. In isolated cases, worsening of psychotic symptoms has been reported in patients receiving amantadine and concomitant neuroleptic medication.

In patients with renal impairment, the dose of amantadine should be reduced. This can be achieved by either reducing the total daily dose, or by increasing the dosage interval in accordance with the creatinine clearance. For example,

The above recommendations are for guidance only and physicians should continue to monitor their patients for signs of unwanted effects.

There have been isolated reports of a suspected interaction between amantadine and combination diuretics (hydrochlorothiazide + potassium sparing diuretics). One or both of the components apparently reduce the clearance of amantadine, leading to higher plasma concentrations and toxic effects (confusion, hallucinations, ataxia, myoclonus).

Concurrent administration of amantadine and drugs or substances (e.g. alcohol) acting on the CNS may result in additive CNS toxicity. Close observation is recommended.

In isolated cases, worsening of psychotic symptoms has been reported in patients receiving amantadine and concomitant neuroleptic medication.

There have been isolated reports of precipitation or aggravation of neuroleptic malignant syndrome or neuroleptic induced catatonia following the withdrawal of amantadine in patients taking neuroleptic agents. A similar syndrome has also been reported rarely following withdrawal of amantadine and other anti-parkinson agents in patients who were not taking concurrent psychoactive medication.

Peripheral oedema (thought to be due to an alteration in the responsiveness of peripheral vessels) may occur in some patients during chronic treatment (not usually before 4 weeks) with amantadine. This should be taken into account in patients with congestive heart failure.

Amantadine has anticholinergic effects, it should not be given to patients with untreated angle closure glaucoma.

If blurred vision or other visual problems occur an ophthalmologist should be contacted to exclude corneal oedema. In case that corneal oedema is diagnosed treatment with amantadine should be discontinued.

Patients should be regularly monitored for the development of impulse control disorders. Patients and carers should be made aware that behavioural symptoms of impulse control disorders, including pathological gambling, increased libido, hypersexuality, compulsive spending or buying, binge eating and compulsive eating can occur in patients treated with products with a dopaminergic effect, including amantadine. Dose reduction or tapered discontinuation should be considered if such symptoms develop.

Amantadine-related complications during pregnancy have been reported. Amantadine is contraindicated during pregnancy and in women trying to become pregnant.

Amantadine is excreted in human milk. Undesirable effects have been reported in breastfed infants. Amantadine should not be used during breast-feeding.

Fertility

There are insufficient data to adequately assess effects on the reproductive system.

Patients should be warned of the potential hazards of driving or operating machinery if they experience side effects such as dizziness or blurred vision.