Memantine Hydrochloride Milpharm Limited (Memantine Hydrochloride)

Memantine is used in the management of Alzheimer’s disease, acting on the glutamatergic pathway to support cognitive function.

• Alzheimer’s disease (moderate to severe): improves cognition and daily functioning in patients with advanced disease.
• Alzheimer’s disease (mild to moderate): may be used as adjunct therapy together with cholinesterase inhibitors.
• Behavioral symptoms of Alzheimer’s disease: can help reduce agitation and aggression when prescribed by a physician.

• 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 overstimulation with glutamate, thereby reducing excitotoxic neuronal injury that contributes to cognitive decline in Alzheimer’s disease.

Memantine is associated with a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Dizziness: transient sensation of light‑headedness.
• Headache: mild to moderate intensity.
• Constipation: reduced bowel movements.
• Fatigue: feeling unusually tired.
• Nausea: mild stomach upset.
• Confusion: occasional disorientation.

Serious or Rare Side Effects

• Seizures: rare occurrence of convulsive episodes.
• Severe allergic reaction: rash, swelling, or difficulty breathing.
• Hallucinations: visual or auditory disturbances.
• Hypertension: sudden increase in blood pressure.

When prescribing memantine, clinicians should consider several safety aspects.

• Renal impairment: dose adjustment may be required in patients with reduced kidney function.
• Hepatic disease: monitor liver enzymes and consider dose modification.
• Concomitant CNS disorders: use caution in patients with epilepsy or other seizure disorders.
• Pregnancy and breastfeeding: avoid use unless benefits clearly outweigh potential risks.
• Elderly patients: start at low dose and titrate slowly to minimize adverse effects.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, and protect from moisture.

Memantine may interact with other medicines, influencing its efficacy or safety.

Major Interactions (Avoid)

• Amantadine: combined NMDA antagonism can increase risk of neuropsychiatric effects.
• Ketamine: additive NMDA blockade may lead to severe dizziness or confusion.

Moderate Interactions (Monitor Closely)

• Anticholinesterases (e.g., donepezil): monitor for additive cognitive effects.
• Diuretics (e.g., furosemide): may increase serum memantine concentrations.
• Antihypertensives: observe for potential blood pressure changes.