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
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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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            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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            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.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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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.