Namenda XR 28mg Capsules
It is used to treat dementia in people with Alzheimer's disease.
Drug Class
Agents for Alzheimer's Disease
Pharmacologic Class
N-methyl-D-aspartate (NMDA) Receptor Antagonist
Pregnancy Category
Category B
FDA Approved
Jun 2010
DEA Schedule
Not Controlled
Overview
What is this medicine?
Memantine extended-release is a medication used to treat moderate to severe Alzheimer's disease. It works by affecting certain chemicals in the brain that are involved in memory and thinking. It may help improve memory, awareness, and the ability to perform daily activities, but it is not a cure for Alzheimer's disease.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food, and continue taking it even if you feel well. It's essential to swallow the medication whole; do not chew or crush it. If you notice any unusual appearance or damage to the capsules, do not take them.
If you have difficulty swallowing the medication whole, you can sprinkle the contents onto applesauce. However, be sure to swallow the mixture immediately without chewing.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding bathrooms. Keep all medications in a safe place, out of reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless instructed to do so. Instead, consult your pharmacist for guidance on the best disposal method or explore local drug take-back programs.
Missing a Dose
If you miss a dose, skip it and resume your regular schedule. Do not take two doses at the same time or extra doses. If you miss taking your medication for several days in a row, contact your doctor before restarting your medication regimen.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food, and continue taking it even if you feel well. It's essential to swallow the medication whole; do not chew or crush it. If you notice any unusual appearance or damage to the capsules, do not take them.
If you have difficulty swallowing the medication whole, you can sprinkle the contents onto applesauce. However, be sure to swallow the mixture immediately without chewing.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding bathrooms. Keep all medications in a safe place, out of reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless instructed to do so. Instead, consult your pharmacist for guidance on the best disposal method or explore local drug take-back programs.
Missing a Dose
If you miss a dose, skip it and resume your regular schedule. Do not take two doses at the same time or extra doses. If you miss taking your medication for several days in a row, contact your doctor before restarting your medication regimen.
Lifestyle & Tips
- Take the capsule whole; do not chew, crush, or divide it.
- Can be taken with or without food.
- If you miss a dose, take it as soon as you remember, unless it's almost time for your next dose. Do not take two doses at once.
- Store at room temperature, away from moisture and heat.
- Continue other prescribed treatments and follow your doctor's recommendations for managing Alzheimer's disease.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 7 mg once daily. Titrate weekly by 7 mg increments to a target maintenance dose of 28 mg once daily.
Dose Range:
7 - 28 mg
Condition-Specific Dosing:
Alzheimer's Disease (moderate to severe):
Start 7 mg once daily, increase to 14 mg/day (Week 2), 21 mg/day (Week 3), and 28 mg/day (Week 4 and beyond).
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment necessary (CrCl 50-80 mL/min).
Moderate:
No dosage adjustment necessary (CrCl 30-49 mL/min).
Severe:
Maximum recommended dose is 14 mg once daily (CrCl 5-29 mL/min).
Dialysis:
Maximum recommended dose is 14 mg once daily. Memantine is not significantly removed by hemodialysis.
Hepatic Impairment:
Mild:
No dosage adjustment necessary.
Moderate:
No dosage adjustment necessary.
Severe:
Use with caution; dosage adjustment may be considered, but specific recommendations are not available due to limited data.
Pharmacology
Mechanism of Action
Memantine is a low to moderate affinity uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. It binds to the NMDA receptor-operated cation channels with a voltage-dependent affinity and blocks the effects of abnormally elevated tonic levels of glutamate, which may lead to neuronal dysfunction. It does not interfere with the physiological activation of NMDA receptors required for memory formation and learning.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 100%
Tmax:
Approximately 9-12 hours (extended-release)
FoodEffect:
Food does not affect the absorption of memantine extended-release capsules.
Distribution:
Vd:
Approximately 9-11 L/kg
ProteinBinding:
Approximately 45%
CnssPenetration:
Yes
Elimination:
HalfLife:
Approximately 60-80 hours
Clearance:
Approximately 105 mL/min
ExcretionRoute:
Primarily renal (75-90% unchanged)
Unchanged:
Approximately 75-90%
Pharmacodynamics
OnsetOfAction:
Gradual, over weeks with titration
PeakEffect:
Achieved at steady-state concentrations, typically after 2-3 weeks of consistent dosing.
DurationOfAction:
Maintained with once-daily dosing due to long half-life.
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Feeling confused
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or persist, contact your doctor for guidance:
Dizziness or headache
Diarrhea or constipation
Note: This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor can provide medical advice on managing side effects.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Feeling confused
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or persist, contact your doctor for guidance:
Dizziness or headache
Diarrhea or constipation
Note: This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor can provide medical advice on managing side effects.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or fainting
- Severe headache
- New or worsening confusion or hallucinations
- Difficulty urinating or changes in urination
- Unusual weakness or tiredness
- Signs of an allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This information will help your doctor and pharmacist identify potential interactions between this medication and other substances.
* Any health problems you have, as this medication may interact with certain conditions.
To ensure your safety, it is crucial to verify that this medication can be taken with all your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This information will help your doctor and pharmacist identify potential interactions between this medication and other substances.
* Any health problems you have, as this medication may interact with certain conditions.
To ensure your safety, it is crucial to verify that this medication can be taken with all your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are pregnant, planning to become pregnant, or are breast-feeding, be sure to discuss this with your doctor. You and your doctor will need to carefully weigh the benefits and risks of using this medication to ensure the best possible outcome for both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe dizziness
- Agitation
- Confusion
- Hallucinations
- Seizures
- Slowed heart rate
- Vomiting
- Unconsciousness
What to Do:
Seek immediate medical attention or call Poison Control at 1-800-222-1222. Bring the medication bottle with you.
Drug Interactions
Major Interactions
- Other NMDA antagonists (e.g., amantadine, ketamine, dextromethorphan): Concomitant use may increase the frequency and severity of adverse reactions due to additive pharmacodynamic effects.
- Drugs that alkalinize urine (e.g., carbonic anhydrase inhibitors, sodium bicarbonate): May decrease renal elimination of memantine, leading to increased plasma levels and potential toxicity.
Moderate Interactions
- Cimetidine, ranitidine, quinidine, nicotine: May alter memantine excretion by competing for renal tubular secretion.
- Hydrochlorothiazide: May reduce memantine clearance.
Monitoring
Baseline Monitoring
Cognitive and functional assessment (e.g., MMSE, ADAS-Cog)
Rationale: To establish baseline severity of Alzheimer's disease and guide treatment initiation.
Timing: Prior to initiation of therapy.
Renal function (CrCl)
Rationale: To determine appropriate dosing, especially in patients with renal impairment.
Timing: Prior to initiation of therapy.
Routine Monitoring
Clinical response (cognitive and functional status)
Frequency: Periodically (e.g., every 3-6 months or as clinically indicated)
Target: Stabilization or improvement in symptoms
Action Threshold: Lack of benefit or worsening symptoms may warrant re-evaluation of therapy.
Adverse effects (e.g., dizziness, headache, confusion, constipation)
Frequency: Regularly, especially during dose titration and initiation
Target: Minimization of side effects
Action Threshold: Persistent or severe adverse effects may require dose reduction or discontinuation.
Symptom Monitoring
- Dizziness
- Headache
- Confusion
- Constipation
- Diarrhea
- Hallucinations
- Cough
- Hypertension
- Somnolence
Special Patient Groups
Pregnancy
Memantine is classified as Pregnancy Category B. Animal studies have shown no evidence of teratogenicity at clinically relevant doses. However, there are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Limited human data; animal studies suggest no increased risk of major birth defects.
Second Trimester:
Limited human data.
Third Trimester:
Limited human data.
Lactation
It is not known whether memantine is excreted in human milk. Due to the potential for serious adverse reactions in breastfed infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
Risk L3 (Moderate Concern) - No human data, but high molecular weight and long half-life suggest potential for accumulation in infant. Monitor for sedation, poor feeding, or other adverse effects.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Not indicated for use in children.
Geriatric Use
No specific dosage adjustment is required based solely on age. However, geriatric patients are more likely to have renal impairment, which may necessitate dose adjustment. Closely monitor for adverse effects, particularly dizziness and confusion.
Clinical Information
Clinical Pearls
- Memantine extended-release is typically initiated at a low dose and gradually titrated up to the target maintenance dose over several weeks to improve tolerability and minimize side effects like dizziness.
- It can be taken with or without food. The capsules should be swallowed whole and not chewed, crushed, or divided.
- Memantine is often used in combination with cholinesterase inhibitors (e.g., donepezil) for moderate to severe Alzheimer's disease.
- Patients should be advised to maintain adequate hydration, as dehydration can affect renal function and memantine clearance.
- Monitor for changes in mental status, particularly confusion or hallucinations, which can be side effects or signs of disease progression.
Alternative Therapies
- Donepezil (Aricept)
- Rivastigmine (Exelon)
- Galantamine (Razadyne)
Cost & Coverage
Average Cost:
Varies widely, typically $100-$400+ per 30 capsules
Generic Available:
Yes
Insurance Coverage:
Most prescription drug plans (Medicare Part D, commercial insurance) typically cover generic memantine. Brand-name Namenda XR may be Tier 2 or 3, requiring higher co-pays or prior authorization.
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it occurred.