Memantina Alter (Memantine Hydrochloride)

• Memantine is an NMDA receptor antagonist used in the management of neurodegenerative disorders.
• Alzheimer’s disease (moderate to severe): improves cognition and global clinical status
• Alzheimer’s disease (mild to moderate): may be added to cholinesterase inhibitors to support cognition
• Alzheimer’s disease (behavioral symptoms): may help reduce agitation and aggression

• Memantine acts as a non‑competitive antagonist at the NMDA (N‑methyl‑D‑aspartate) receptor. By binding to the receptor-associated ion channel with moderate affinity, it blocks excessive calcium influx caused by prolonged glutamate activation, thereby reducing excitotoxic neuronal injury while preserving normal synaptic transmission essential for learning and memory.

Common Side Effects

• Dizziness: transient light‑headedness, especially after dose initiation
• Headache: mild to moderate intensity, often resolves with continued therapy
• Constipation: reduced bowel movements, manageable with dietary fiber
• Confusion: occasional disorientation, particularly in elderly patients
• Somnolence: mild sleepiness, may improve over time

Serious or Rare Side Effects

• Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis
• Seizures: rare but may occur, especially with high plasma levels
• Hallucinations or psychosis: uncommon, warrant immediate medical review
• Cardiac arrhythmias: rare cases of QT prolongation reported
• Hepatic dysfunction: elevated liver enzymes in isolated reports

• Memantine should be used with caution in specific clinical situations.
• Renal impairment: dose adjustment may be required in patients with reduced kidney function
• History of seizures: monitor closely for increased seizure activity
• Concurrent NMDA antagonists: avoid co‑administration to prevent additive CNS effects
• Cardiovascular disease: monitor blood pressure and heart rhythm during therapy
• Pregnancy and lactation: use only if potential benefit justifies potential risk to fetus or infant
• Store at ambient temperature: keep in original container, protect from moisture and direct sunlight

Memantine may interact with several medications; monitoring is advised.

Major Interactions (Avoid)

• Amantadine: increased risk of neurotoxicity when combined
• Other NMDA antagonists (e.g., ketamine): additive central nervous system depression
• High‑dose quinidine: may raise memantine plasma concentrations

Moderate Interactions (Monitor Closely)

• Anticholinergic agents: possible reduction in therapeutic benefit
• Loop diuretics (e.g., furosemide): may increase memantine levels
• CNS depressants (e.g., benzodiazepines): enhanced sedation or drowsiness