memantina

Memantine is a prescription medication used to treat moderate to severe Alzheimer's disease. It acts as a noncompetitive NMDA receptor antagonist, reducing excessive glutamate activity in the brain and helping protect neurons from excitotoxicity. Memantine is approved in many countries and is sold under brand names such as Namenda. It may be prescribed alone or in combination with cholinesterase inhibitors, depending on the clinical situation.

Memantine is taken by mouth as tablets or an oral solution. Dosing is typically titrated to minimize side effects: immediate-release tablets are commonly started at 5 mg once daily for one week, then 5 mg twice daily, and finally 10 mg twice daily. An extended-release formulation starts at 7 mg daily and increases to 28 mg once daily over several weeks. The drug is largely excreted unchanged by the kidneys, so renal impairment requires dose adjustment. Its half-life is relatively long, which supports gradual titration and steady drug exposure.

Common adverse effects include dizziness, headache, confusion, constipation, and hypertension. Less frequent effects include nausea, vomiting, and skin rash; some patients may experience agitation or worsening of cognitive symptoms. Memantine can interact with other NMDA receptor antagonists and certain medications; caution is advised in people with kidney disease or dehydration. It is contraindicated in individuals with a known hypersensitivity to memantine. The overall treatment effect is modest and varies among individuals.

Memantine was approved by the U.S. Food and Drug Administration in 2003 for moderate-to-severe Alzheimer's disease and is used worldwide as part of a comprehensive care plan.