Products
Memantine is commercially available as film-coated tablets, meltable tablets, and oral solution (Axura, Ebixa). It has been approved in many countries since 2003. Generic versions were registered in 2014.
Structure and properties
Memantine (C12H21N, Mr = 179.3 g/mol) is present in drugs as memantine hydrochloride, a white powder that is insoluble in water. Memantine is an organic cation and an aminodimethyladamantane that is structurally closely related to the influenza and Parkinson’s disease drug amantadine.
Effects
Memantine (ATC N06DX01) is a voltage-dependent, noncompetitive, intermediate affinity NMDA receptor antagonist. Persistent excitation of the central nervous system by glutamate at the NMDA receptor may contribute to the symptomatology of Alzheimer’s disease.
Indications
For symptomatic treatment of moderate to severe Alzheimer’s disease.
Dosage
According to the SmPC. The drug is gradually dosed up at the beginning and may be administered with or without food. Memantine has a long half-life of 60 to 100 hours.
Contraindications
- Hypersensitivity
Memantine should not be given with the cough suppressant dextromethorphan because it is also an NMDA antagonist. Full precautions can be found in the drug label.
Interactions
Drug interactions are possible with the following agents: levodopa, dopamine agonists, anticholinergics, barbiturates, neuroleptics, dantrolene, baclofen, amantadine, ketamine, dextromethorphan, phenytoin, organic cations, hydrochlorothiazide, and warfarin.
Adverse effects
The most common possible adverse effects include headache, drowsiness, dizziness, constipation, increased blood pressure, and difficulty breathing.
