Memantina Vitória (Memantine Hydrochloride)

• Memantine Hydrochloride is employed in the therapeutic management of neurodegenerative conditions, acting on the glutamatergic excitatory system to reduce neuronal over‑activation. Its primary approved use is in Alzheimer’s disease, where it helps to preserve cognitive function and daily living activities.
• Alzheimer's disease: provides modest improvement in memory, attention, and the ability to perform everyday tasks for patients with mild to moderate disease, and may delay functional decline when used as part of a comprehensive treatment plan.

• Memantine Hydrochloride acts as a non‑competitive antagonist at the N‑methyl‑D‑aspartate (NMDA) receptor. By binding to the receptor-associated ion channel with moderate affinity, it blocks excessive calcium influx caused by prolonged glutamate stimulation, thereby reducing excitotoxic neuronal injury while preserving normal synaptic transmission essential for learning and memory. This selective inhibition helps to balance excitatory neurotransmission without completely suppressing physiological NMDA activity.

Like all medicines, Memantine Hydrochloride may be associated with adverse reactions, which are classified by frequency and severity.

Common Side Effects

• Dizziness: sensation of light‑headedness or unsteadiness.
• Headache: mild to moderate pain in the head region.
• Constipation: reduced bowel movements or hard stools.
• Fatigue: feeling unusually tired or lacking energy.

Serious or Rare Side Effects

• Seizures: occurrence of convulsive episodes requiring medical attention.
• Hallucinations: visual or auditory disturbances not based in reality.
• Severe rash or skin reactions: including Stevens‑Johnson syndrome.
• Elevated liver enzymes: indicating possible hepatic stress.
• Suicidal thoughts: emergence of depressive ideation.
• Cardiac arrhythmia: irregular heart rhythm observed on monitoring.

Before initiating therapy, clinicians should consider several safety aspects to optimize patient outcomes.

• Renal function monitoring: adjust dose in patients with impaired clearance.
• Hepatic impairment: use with caution in severe liver disease.
• History of seizures: monitor for increased seizure activity.
• Concomitant NMDA agonists: avoid combined use due to antagonistic effects.
• Pregnancy and lactation: safety not established; weigh benefits against risks.
• Store at room temperature: keep in original container, protect from moisture and direct sunlight.

Memantine Hydrochloride can interact with other medicines, influencing efficacy or safety.

Major Interactions (Avoid)

• Amantadine: concurrent use may increase risk of neuropsychiatric effects.
• Ketamine: additive NMDA antagonism can lead to excessive CNS depression.
• Other NMDA antagonists: combined therapy may amplify adverse neurological events.

Moderate Interactions (Monitor Closely)

• CNS depressants (e.g., benzodiazepines): may enhance sedation.
• Anticholinergic agents: could reduce cognitive benefits of memantine.
• Diuretics: may affect electrolyte balance, requiring periodic labs.