Comparative Pharmacology
Head-to-head clinical analysis: MEMANTINE HYDROCHLORIDE versus NUEDEXTA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MEMANTINE HYDROCHLORIDE versus NUEDEXTA.
MEMANTINE HYDROCHLORIDE vs NUEDEXTA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Uncompetitive NMDA receptor antagonist with moderate affinity; blocks pathological tonic activation of glutamatergic neurotransmission while preserving physiologic phasic activation.
NUEDEXTA is a combination of dextromethorphan (an NMDA receptor antagonist and sigma-1 receptor agonist) and quinidine (a CYP2D6 inhibitor). The mechanism by which dextromethorphan exerts therapeutic effects in pseudobulbar affect is unknown, but it is thought to involve modulation of glutamatergic neurotransmission via NMDA receptor antagonism and sigma-1 receptor agonism. Quinidine increases dextromethorphan plasma concentrations by inhibiting its CYP2D6-mediated metabolism.
Initial 5 mg orally once daily; may increase by 5 mg per week to target dose of 10 mg twice daily (20 mg/day).
NUEDEXTA (dextromethorphan hydrobromide 20 mg / quinidine sulfate 10 mg) is administered orally once daily in the morning for 7 days, then increased to twice daily (every 12 hours).
None Documented
None Documented
Terminal elimination half-life is 60-80 hours (mean ~70 hours) in young adults, extending to 100-120 hours in elderly patients. This long half-life allows once-daily dosing.
Dextromethorphan: ~13 hours (range 9-19 hours) when co-administered with quinidine due to CYP2D6 inhibition; quinidine: ~6-8 hours. Clinical context: Steady-state achieved in approximately 3 days; half-life prolongation allows twice-daily dosing.
Renal excretion of unchanged drug accounts for approximately 57-82% of the administered dose. Fecal excretion represents about 5-10% via biliary elimination. Overall, 80-90% is eliminated as parent compound or metabolites in urine.
Renal excretion of unchanged drug and metabolites: dextromethorphan and metabolites (including dextrorphan) undergo renal elimination; quinidine is primarily hepatically metabolized, with <20% excreted unchanged in urine. Fecal elimination is minor (<5%).
Category A/B
Category C
NMDA Receptor Antagonist
NMDA Receptor Antagonist