Namenda

Generic name:

Memantine hydrochloride

Drug class:

N-Methyl-D-aspartate (NMDA) receptor antagonist

Dosage form:

• Immediate-release tablets: 5 mg, 10 mg
• Extended-release capsules: 7 mg, 14 mg, 21 mg, 28 mg
• Oral solution: 2 mg/mL

Route of administration:

Oral

Dose:

• Immediate-release: Start 5 mg once daily; increase by 5 mg weekly to 10 mg twice daily
• Extended-release: Start 7 mg once daily; increase by 7 mg weekly to a maximum of 28 mg once daily
• Renal impairment: Dosage reduction required; varies by creatinine clearance

Mechanism of action:

Noncompetitive antagonist at NMDA-type glutamate receptors, reducing pathological calcium influx and excitotoxic neuronal damage.

Drug usage cases:

• Approved: Moderate to severe Alzheimer’s disease
• Off-label: Mild cognitive impairment
• Off-label: Vascular dementia
• Off-label: Dementia with Lewy bodies
• Off-label: Frontotemporal dementia
• Off-label: Neuropathic pain
• Off-label: Autism spectrum disorders
• Off-label: Obsessive-compulsive disorder (adjunctive)
• Off-label: Schizophrenia (negative symptoms adjunctive)

Drug contra indications:

• Hypersensitivity to memantine or any formulation component
• Severe renal impairment without dose adjustment (use with caution)

Side effects:

• Dizziness
• Headache
• Confusion
• Somnolence
• Insomnia
• Agitation
• Hallucinations
• Constipation
• Diarrhea
• Hypertension
• Urinary tract infection
• Cough
• Weight gain
• Vomiting
• Back pain

Warnings:

• Renal impairment: Dose adjustment required for creatinine clearance ≤30 mL/min
• Seizure risk: Use with caution in patients with epilepsy or CNS lesions
• Urinary retention: Caution in patients with bladder outflow obstruction
• Cardiovascular: Orthostatic hypotension and cardiac conduction abnormalities reported
• Psychiatric: Worsening agitation, aggression, or psychosis may occur
• Hepatic impairment: Use with caution; clinical data limited
• Angle-closure glaucoma: Potential risk due to anticholinergic effects
• Volume depletion: Monitor blood pressure and volume status

Use during pregnancy or breastfeeding:

Animal studies have not demonstrated direct teratogenic effects, but adequate human studies are lacking. Use only if potential benefit justifies potential fetal risk. Memantine is excreted in breast milk; monitor nursing infants for adverse reactions and consider discontinuation or alternative therapy.