Memantine Tablets

Mechanism

Memantine selectively blocks NMDA (N-methyl-D-aspartate) receptors, preventing excessive calcium influx into neurons. This reduces excitotoxicity caused by overstimulation of glutamate pathways, protecting neurons and improving synaptic plasticity. Unlike acetylcholinesterase inhibitors, Memantine targets glutamatergic dysfunction, complementing cholinergic therapies in Alzheimer’s disease.

Pharmacokinetics

• Bioavailability: ~100%
• Peak plasma concentration: 3–8 hours
• Protein binding: ~45%
• Metabolism: Minimal hepatic metabolism
• Half-life: ~60–80 hours
• Excretion: Primarily unchanged in urine

Side Effects

• Nausea
• Dizziness
• Headache
• Confusion
• Constipation
• Hallucinations (rare)

Contraindication

• Hypophosphatemia
• Hypersensitivity to Memantine
• Severe renal impairment (dose adjustment required)
• Pregnancy and lactation (unless benefits outweigh risks)

Interaction

• Other NMDA antagonists (e.g., amantadine, ketamine): additive effects
• Drugs affecting urinary pH (e.g., carbonic anhydrase inhibitors): altered excretion
• Anticholinergics: potential additive cognitive effects

Warning and Precautions

• Monitor renal function regularly
• Use caution in patients with seizure disorders
• May cause dizziness — advise caution with driving or machinery

Dosage

As directed by the Physician.