memantine (Rx)

Brand and Other Names:Namenda XR, Namenda
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 5mg
  • 10mg

capsule, extended-release

  • 7mg
  • 14mg
  • 21mg
  • 28mg

oral solution

  • 2mg/mL

Alzheimer-Type Dementia

Treatment of moderate-to-severe dementia

Tablet: 5 mg PO once daily initially; increased by increments of 5 mg/day each week; maintenance target dosage (>5 weeks): 20 mg/day PO divided q12hr

Extended-release capsule: 7 mg PO qDay initially; may be increased by increments of 7 mg/day each week; maintenance target dose is 28 mg PO qDay

Dosage Modifications

Renal impairment

  • Mild or moderate: No dosage adjustment required
  • Severe: (CrCl 5-29 mL/min): Not to exceed 14 mg/day (extended-release) or 5 mg BID (prompt-release)

Hepatic impairment

  • Mild or moderate (Child Pugh A/B): No dosage adjustment required
  • Severe (Child Pugh C): Caution

Administration

May take with or without food

Consume entire capsule contents, do not divide the dose

Swallow capsule whole or open and sprinkle on spoonful of applesauce; do not chew or crush

Do not mix oral solution with any other liquid

Missed dose: Do not double next dose, the next dose should be taken as scheduled; if missed for several days, dosing may need to be resumed at lower doses and retitrated as described above

Mild-to-Moderate Vascular Dementia (Off-label)

5 mg (immediate-release) PO qDay; titrate by 5 mg q7days to target dose 10 mg twice daily

Not indicated

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Interactions

Interaction Checker

and memantine

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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             activity indicator 

            Contraindicated (0)

              Serious - Use Alternative (4)

              • dextromethorphan

                memantine, dextromethorphan. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.

              • ketamine

                memantine, ketamine. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.

              • tafenoquine

                tafenoquine will increase the level or effect of memantine by Other (see comment). Avoid or Use Alternate Drug. Tafenoquine inhibits organic cation transporter-2 (OCT2) and multidrug and toxin extrusion (MATE) transporters in vitro. Avoid coadministration with OCT2 or MATE substrates. If coadministration cannot be avoided, monitor for substrate-related toxicities and consider dosage reduction if needed based on product labeling of the coadministered drug.

              • trilaciclib

                trilaciclib will decrease the level or effect of memantine by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of trilaciclib (OCT2, MATE1, and MATE-2K inhibitor) with substrates where minimal increased concentration in kidney or blood may lead to serious or life-threatening toxicities.

              Monitor Closely (16)

              • acetazolamide

                acetazolamide will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

              • aluminum hydroxide

                aluminum hydroxide will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

              • amantadine

                memantine, amantadine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Combination may lead to additive adverse effects. If coadministration cannot be avoided, monitor for increased adverse effects such as agitation, dizziness and other CNS events.

              • amiodarone

                amiodarone will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • calcium carbonate

                calcium carbonate will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

              • cimetidine

                cimetidine will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • digoxin

                digoxin will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • dofetilide

                dofetilide will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • erdafitinib

                memantine increases levels of erdafitinib by decreasing renal clearance. Modify Therapy/Monitor Closely. Consider alternatives that are not OCT2 substrates or consider reducing the dose of OCT2 substrates based on tolerability.

              • procainamide

                memantine will increase the level or effect of procainamide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • quinidine

                quinidine will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

              • sodium bicarbonate

                sodium bicarbonate will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

              • sodium citrate/citric acid

                sodium citrate/citric acid will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

              • sodium lactate

                sodium lactate will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

              • tenofovir DF

                tenofovir DF increases levels of memantine by decreasing renal clearance. Use Caution/Monitor. Potential for increased toxicity. .

              • vandetanib

                vandetanib increases levels of memantine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Vandetanib inhibits the uptake of substrates of organic cation transporter type 2 (OCT2).

              Minor (11)

              • hydrochlorothiazide

                hydrochlorothiazide will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • metformin

                memantine will increase the level or effect of metformin by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • methyclothiazide

                methyclothiazide will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • midodrine

                memantine will increase the level or effect of midodrine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • ofloxacin

                memantine will increase the level or effect of ofloxacin by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • pramipexole

                memantine will increase the level or effect of pramipexole by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • quinine

                memantine will increase the level or effect of quinine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • sulfamethoxazole

                sulfamethoxazole will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • triamterene

                memantine will increase the level or effect of triamterene by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • trimethoprim

                memantine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

              • verapamil

                memantine will increase the level or effect of verapamil by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

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              Adverse Effects

              1-10%

              Dizziness (7%)

              Confusion (6%)

              Headache (6%)

              Constipation (5%)

              Cough (4%)

              Hypertension (4%)

              Backache (3%)

              Pain (3%)

              Somnolence (3%)

              Syncope (3%)

              Vomiting (3%)

              Dyspnea (2%)

              Fatigue (2%)

              <1%

              Acute renal failure

              Cerebral infarction

              Cerebrovascular accident

              Deep venous thrombosis

              Hepatitis, liver failure

              Intracranial hemorrhage

              Neuroleptic malignant syndrome

              Seizure (including grand mal)

              Stevens-Johnson syndrome

              Transient ischemic attack

              Postmarketing Reports

              Blood and lymphatic system disorders: Agranulocytosis, leukopenia (including neutropenia), pancytopenia, thrombocytopenia, thrombotic thrombocytopenic purpura

              Cardiac disorders: Cardiac failure congestive

              Gastrointestinal disorders: Pancreatitis

              Hepatobiliary disorders: Hepatitis

              Psychiatric disorders: Suicidal ideation

              Renal and urinary disorders: Acute renal failure (including increased creatinine and renal insufficiency)

              Skin disorders: Stevens Johnson syndrome

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              Warnings

              Contraindications

              Hypersensitivity to memantine or components of the formulation

              Cautions

              Not evaluated in patients with seizure disorder; seizures occurred in 0.2% of patients

              Conditions that raise urine pH may decrease urinary elimination and increase plasma levels of memantine

              Use caution in cardiovascular disease, seizure disorder, ophthalmic disease, hepatic and/or renal impairment

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              Pregnancy & Lactation

              Pregnancy

              There are no adequate data on developmental risk associated with use; adverse developmental effects (decreased body weight, and skeletal ossification) observed in offspring of rats during pregnancy at doses associated with minimal maternal toxicity; doses are higher than used in humans at maximum recommended daily dose

              Animal data

              • Oral administration to rats during period of organogenesis resulted in decreased skeletal ossification in fetuses at highest dose tested; the higher no-effect dose (6 mg/kg/day) was approximately 3 times MRHD on a mg/m² basis
              • Oral administration of memantine to rabbits during period of organogenesis resulted in no adverse developmental effects; highest dose tested was approximately 30 times the MRHD on a mg/m² basis
              • Oral administration to rats from late gestation throughout lactation to weaning, resulted in decreased pup weights at highest dose tested; the higher no-effect dose (6 mg/kg/day) is approximately 3 times the MRHD on a mg/ m² basis

              Lactation

              There are no data on presence of drug in human milk, effects on breastfed infant, or on milk production

              Developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from drug or from underlying maternal condition

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

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              Pharmacology

              Mechanism of Action

              Low- to moderate-affinity uncompetitive N-methyl-D-aspartate (NMDA) receptor (NMDAR) antagonist that binds preferentially to NMDAR-operated cation channels, blocking receptor only under conditions of excessive stimulation, with no effect on normal neurotransmission

              Absorption

              Peak plasma time: 3-7 hr (immediate release); 9-12 hr (extended release)

              Distribution

              Protein bound: 45%

              Vd: 9-11 L/kg

              Metabolism

              Metabolites: 3 polar metabolites (minimally active)

              Elimination

              Half-life: 60-80 hr

              Excretion: Urine (74%)

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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              Namenda Titration Pak oral
              -
              5-10 mg tablet
              memantine oral
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              14 mg capsule
              memantine oral
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              7 mg capsule
              memantine oral
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              5 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              28 mg capsule
              memantine oral
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              21 mg capsule
              memantine oral
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              14 mg capsule
              memantine oral
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              7 mg capsule
              memantine oral
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              5 mg tablet
              memantine oral
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              2 mg/mL solution
              memantine oral
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              5 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
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              28 mg capsule
              memantine oral
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              21 mg capsule
              memantine oral
              -
              14 mg capsule
              memantine oral
              -
              7 mg capsule
              memantine oral
              -
              21 mg capsule
              memantine oral
              -
              14 mg capsule
              memantine oral
              -
              5 mg tablet
              memantine oral
              -
              21 mg capsule
              memantine oral
              -
              10 mg tablet
              memantine oral
              -
              2 mg/mL solution
              memantine oral
              -
              7 mg capsule
              memantine oral
              -
              14 mg capsule
              memantine oral
              -
              28 mg capsule
              memantine oral
              -
              28 mg capsule
              memantine oral
              -
              7 mg capsule
              memantine oral
              -
              28 mg capsule
              memantine oral
              -
              10 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
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              10 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
              -
              2 mg/mL solution
              memantine oral
              -
              2 mg/mL solution
              memantine oral
              -
              28 mg capsule
              memantine oral
              -
              14 mg capsule
              memantine oral
              -
              10 mg tablet
              memantine oral
              -
              5 mg tablet
              memantine oral
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              7 mg capsule
              memantine oral
              -
              5 mg tablet
              memantine oral
              -
              5-10 mg tablet
              memantine oral
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              5 mg tablet
              memantine oral
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              10 mg tablet
              Namenda oral
              -
              10 mg tablet
              Namenda oral
              -
              5 mg tablet
              Namenda XR oral
              -
              28 mg capsule
              Namenda XR oral
              -
              21 mg capsule
              Namenda XR oral
              -
              14 mg capsule
              Namenda XR oral
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              7 mg capsule
              Namenda XR oral
              -
              7-14-21-28 mg capsule

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Patient Education
              memantine oral

              MEMANTINE EXTENDED-RELEASE - ORAL

              (MEM-an-teen)

              COMMON BRAND NAME(S): Namenda XR

              USES: Memantine is used to treat moderate to severe confusion (dementia) related to Alzheimer's disease. It does not cure Alzheimer's disease, but it may improve memory, awareness, and the ability to perform daily functions. This medication works by blocking the action of a certain natural substance in the brain (glutamate) that is believed to be linked to symptoms of Alzheimer's disease.

              HOW TO USE: Read the Patient Information Leaflet if available from your pharmacist before you start taking memantine and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Take this medication by mouth with or without food as directed by your doctor, usually once daily. Swallow the capsules whole. Do not crush or chew the capsules. Doing so can release all of the drug at once, increasing the risk of side effects. If you have trouble swallowing the capsules whole, the capsule may be opened and the contents may be sprinkled on applesauce. Swallow all of the drug/food mixture right away without chewing. Do not prepare a supply in advance.The dosage is based on your medical condition and response to treatment. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully.If switching from another form of memantine to the extended-release form, follow your doctor's instructions carefully. Do not switch forms of memantine without talking to your doctor first.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.Tell your doctor if your condition worsens.

              SIDE EFFECTS: Back pain, dizziness, drowsiness, constipation, increased weight, stomach pain, vomiting, and loss of bladder control may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as depression, aggression).A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Before taking memantine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, severe urinary tract infections, recent dietary change (from a high-protein diet to a vegetarian diet).This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.

              DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: carbonic anhydrase inhibitors (such as acetazolamide, methazolamide), sodium bicarbonate.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: restlessness, personality change, hallucinations, loss of consciousness.

              NOTES: Do not share this medication with others.

              MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.If you forget to take memantine for several days, talk to your doctor before your next dose. You may need to start at a lower dose again and slowly increase it.

              STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

              Information last revised October 2018. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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              Formulary

              FormularyPatient Discounts

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              The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
              2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
              3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
              4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
              5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
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              NC NOT COVERED – Drugs that are not covered by the plan.
              Code Definition
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              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.