Memantine: Difference between revisions

| generic           = Memantine

| brand             = Namenda (IR), Namenda XR (extended-release), Namzaric (with donepezil)

| structure         =

| classes           = [[:Category:Anti-dementia medicines|Anti-dementia medicine]], [[:Category:NMDA receptor antagonists|NMDA receptor antagonist (uncompetitive, low-affinity)]], [[:Category:Adamantanes|Adamantane derivative]]

| uses             = <vote slug="alzheimer-moderate-severe-use">Alzheimer disease dementia, moderate to severe (FDA, often with donepezil)</vote>, <vote slug="vascular-dementia-memantine-use">Vascular dementia (off-label)</vote>, <vote slug="lewy-body-dementia-use">Lewy body dementia (off-label)</vote>, <vote slug="parkinson-disease-dementia-use">Parkinson disease dementia (off-label)</vote>

| starting_dose     = 5 mg PO once daily; titrate by 5 mg weekly to target 10 mg PO BID. XR formulation: 7 mg/day, titrate to 28 mg/day

| preparations     = IR tablets 5, 10 mg; oral solution 2 mg/mL; XR capsules 7, 14, 21, 28 mg

| fda_max           = 20 mg/day (IR); 28 mg/day (XR)

| pill_id           =

| routes           = Oral

| onset             = Cognitive effect emerges gradually over weeks to months; symptomatic effect only

| duration         = BID dosing for IR; once-daily for XR

| halflife          = 60-100 hours (long)<ref name="namenda-label">FDA Prescribing Information, Namenda (memantine hydrochloride), Allergan/AbbVie, current revision. https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021487s019,021627s019lbl.pdf</ref>

| bioavailability   = ~100% (oral)<ref name="namenda-label" />

| pregnancy        = Limited human data; rarely indicated in pregnancy given the patient population.{{citation needed}}

| legal             = [[USLegal:Prescription only|Rx-only]] in US

| mechanism        = <vote slug="memantine-mech-claim">'''Uncompetitive, voltage-dependent NMDA receptor antagonist''' with low-to-moderate affinity. Binds within the open channel pore, preferentially blocking the pathological tonic NMDA activity that drives glutamate excitotoxicity in Alzheimer disease, while permitting the physiological transient NMDA activity required for long-term potentiation and memory formation. The "Goldilocks affinity" (strong enough to block excess but weak enough to detach during normal synaptic events) distinguishes memantine from high-affinity NMDA antagonists like ketamine, dextromethorphan, and phencyclidine that produce dissociative anesthesia.</vote> Symptomatic-only effect; does not alter the underlying neurodegenerative trajectory. Generally well tolerated; principal adverse effects are dizziness, headache, and confusion. Renally eliminated, with dose adjustment required in severe renal impairment<ref name="namenda-label" />.

[[Category:Anti-dementia medicines]]

[[Category:NMDA receptor antagonists]]