Memantina Generis (Memantine Hydrochloride)

Memantine, an NMDA receptor antagonist, is used in the management of Alzheimer’s disease, a progressive neurodegenerative disorder that impairs memory, reasoning and daily activities.

• Moderate to severe Alzheimer’s disease: improves cognition and daily functioning in adult patients.
• Mild to moderate Alzheimer’s disease (as adjunct to cholinesterase inhibitors): may support cognitive performance.
• Behavioral symptoms of Alzheimer’s disease: may reduce agitation and aggression in some individuals.

• Memantine acts as a non‑competitive antagonist at the NMDA (N‑methyl‑D‑aspartate) receptor. By binding to the receptor-associated ion channel, it reduces excessive calcium influx caused by prolonged glutamate activation, thereby limiting excitotoxic neuronal injury and helping to preserve synaptic function in the brain.

Common Side Effects

• Dizziness: transient light‑headedness, especially at treatment initiation.
• Headache: mild to moderate intensity, often resolves with continued therapy.
• Constipation: reduced bowel movements, manageable with diet or laxatives.
• Confusion: occasional disorientation, typically improves over time.

Serious or Rare Side Effects

• Seizures: rare but may occur, requiring immediate medical attention.
• Severe allergic reaction: rash, swelling, or difficulty breathing.
• Hallucinations or psychosis: uncommon, may necessitate discontinuation.

Memantine should be used with caution in patients with the following considerations:

• Renal impairment: dose adjustment may be required.
• History of seizures: monitor for increased seizure activity.
• Cardiovascular disease: observe blood pressure and heart rate.
• Concomitant use with other NMDA antagonists: avoid additive neurotoxicity.
• Pregnancy: safety not established; use only if potential benefit justifies risk.
• Store at ambient temperature: keep in original container, protect from moisture and direct sunlight.

Memantine may interact with several medicines, requiring attention to avoid adverse outcomes.

Major Interactions (Avoid)

• Amantadine: increased risk of neurotoxicity.
• Other NMDA antagonists (e.g., ketamine): additive central nervous system effects.
• High‑dose anticholinergics: may diminish therapeutic benefit.

Moderate Interactions (Monitor Closely)

• CNS depressants (benzodiazepines, barbiturates): enhanced sedation.
• Loop diuretics (e.g., furosemide): possible elevation of memantine plasma levels.
• Antihypertensive agents: potential for exaggerated blood pressure changes.