Memry Overdosage

Tablet: Signs and symptoms associated with memantine hydrochloride overdosage include agitation, confusion, ECG changes, loss of consciousness, psychosis, restlessness, slowed movement, somnolence, stupor, unsteady gait, visual hallucinations, vertigo, vomiting, and weakness.
In one case of extreme overdosage, the patient survived the intake of up to 2,000 mg memantine hydrochloride showing CNS effects (e.g., coma, diplopia and agitation) which resolved without permanent sequela.
In the event of overdosage, treatment should be symptomatic. No specific antidote for intoxication or overdose is available. Standard clinical procedures to remove active substance material, e.g., gastric lavage, carte medicinalis (main ingredient is activated charcoal; interruption of potential entero-hepatic recirculation), acidification of urine, and forced diuresis, should be used as appropriate.
In case of signs and symptoms of general CNS overstimulation, careful symptomatic clinical treatment should be considered.
Oral soln: There have been reported cases of accidental and intentional overdose with memantine. The highest ingested dose that has been reported in an overdose is 2,000 mg, which resulted to agitation, diplopia, and coma followed by a full recovery without permanent sequelae. Other signs and symptoms of overdose observed in clinical trials and postmarketing studies included asthenia, bradycardia, confusion, diarrhea, dizziness, ECG changes, increased blood pressure, lethargy, loss of consciousness, proconvulsiveness, psychosis, restlessness, slowed movement, somnolence, stupor, gait disturbance, visual hallucinations, vertigo, vomiting, and weakness. Fatal cases of overdoses were not reported during memantine monotherapy and only occurred when memantine was coadministered with several other drugs.
There is no specific antidote for memantine overdose. In the event of overdose, symptomatic and supportive treatment should be provided. An airway should be established and maintained to ensure adequate ventilation and oxygenation. Standard procedures to remove the active substance, such as gastric lavage, carbo medicinalis (the interruption of potential enterohepatic recirculation), forced diuresis, or the administration of activated charcoal should be considered. Cardiac and vital signs should also be monitored. Elimination of memantine can be enhanced by urine acidification.
Careful symptomatic clinical treatment should be considered in case of signs and symptoms of general CNS overstimulation.