Namenda XR 14mg Capsules
It is used to treat dementia in people with Alzheimer's disease.
Drug Class
N-methyl-D-aspartate (NMDA) receptor antagonist
Pharmacologic Class
NMDA receptor antagonist
Pregnancy Category
Category B
FDA Approved
Oct 2010
DEA Schedule
Not Controlled
Overview
What is this medicine?
Namenda XR is a medicine 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, or at least slow down the worsening of these symptoms.
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 damaged or abnormal-looking capsules, do not take them.
If you have difficulty swallowing the medication whole, you can sprinkle the contents on 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 place, avoiding the bathroom. Keep all medications in a safe location, out of the 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 damaged or abnormal-looking capsules, do not take them.
If you have difficulty swallowing the medication whole, you can sprinkle the contents on 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 place, avoiding the bathroom. Keep all medications in a safe location, out of the 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 once daily at the same time each day, with or without food.
- Swallow the capsule whole. Do not chew, crush, or divide the capsule.
- If you have trouble swallowing the capsule, you can open it and sprinkle the entire contents onto a small amount of applesauce. Swallow the mixture immediately without chewing.
- Do not stop taking this medication suddenly without talking to your doctor.
- Inform your doctor about all other medications you are taking, including over-the-counter drugs, supplements, and herbal products, especially those that make your urine more alkaline (e.g., antacids containing sodium bicarbonate).
- Be aware of potential side effects like dizziness, headache, confusion, and constipation. Avoid driving or operating machinery until you know how this medication affects you.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial 7 mg once daily, titrated weekly in 7 mg increments to a target maintenance dose of 28 mg once daily.
Dose Range:
7 - 28 mg
Condition-Specific Dosing:
moderateToSevereAlzheimersDisease:
Initial 7 mg once daily, titrated weekly in 7 mg increments to a target maintenance dose of 28 mg once daily. Doses should be taken at the same time each day, with or without food. Capsules should be swallowed whole and not chewed or crushed. Alternatively, the capsule can be opened and the entire contents sprinkled on a small amount of applesauce and swallowed immediately without chewing.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment is needed (CrCl 50-80 mL/min).
Moderate:
Dosage should be reduced to 14 mg once daily (CrCl 5-29 mL/min).
Severe:
Use is not recommended (CrCl <5 mL/min) due to insufficient data.
Dialysis:
Not recommended due to insufficient data; memantine is not significantly removed by dialysis.
Hepatic Impairment:
Mild:
No dosage adjustment is needed.
Moderate:
No dosage adjustment is needed.
Severe:
Use with caution; not studied in patients with severe hepatic impairment.
Pharmacology
Mechanism of Action
Memantine is a low to moderate affinity uncompetitive (open-channel) N-methyl-D-aspartate (NMDA) receptor antagonist. It binds to the NMDA receptor-operated cation channels, blocking the effects of abnormal excitatory glutamate, which is thought to contribute to the pathophysiology of Alzheimer's disease. It does not interfere with the physiological activation of NMDA receptors required for memory formation and learning.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 100%
Tmax:
9-12 hours (extended-release capsules)
FoodEffect:
Food does not affect the absorption of memantine extended-release capsules.
Distribution:
Vd:
9-11 L/kg
ProteinBinding:
Approximately 45%
CnssPenetration:
Yes
Elimination:
HalfLife:
60-80 hours
Clearance:
Primarily renal clearance, influenced by urine pH.
ExcretionRoute:
Renal
Unchanged:
Approximately 48% (unchanged in urine)
Pharmacodynamics
OnsetOfAction:
Weeks (gradual titration)
PeakEffect:
Weeks (after reaching maintenance dose)
DurationOfAction:
24 hours (due to extended-release formulation and long half-life)
Confidence:
Medium
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 immediately or seek emergency 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
+ Difficulty 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 unusual symptoms that bother you or persist, contact your doctor for guidance:
Dizziness or headache
Diarrhea or constipation
Important 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, don't hesitate to reach out to 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 is available to provide medical advice and guidance 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 immediately or seek emergency 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
+ Difficulty 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 unusual symptoms that bother you or persist, contact your doctor for guidance:
Dizziness or headache
Diarrhea or constipation
Important 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, don't hesitate to reach out to 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 is available to provide medical advice and guidance on managing side effects.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or lightheadedness
- Severe headache
- Increased confusion or agitation
- Hallucinations (seeing or hearing things that are not there)
- Difficulty urinating or changes in urine output
- Unusual weakness or tiredness
- Seizures (rare)
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 assess potential interactions between this medication and other substances you are taking.
* Any existing health problems, 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 current medications and health conditions. Never start, stop, or adjust the dosage 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 assess potential interactions between this medication and other substances you are taking.
* Any existing health problems, 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 current medications and health conditions. Never start, stop, or adjust the dosage 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 breastfeeding, notify your doctor immediately. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby to make an informed decision.
Overdose Information
Overdose Symptoms:
- Severe dizziness
- Agitation
- Confusion
- Hallucinations
- Restlessness
- Slowed heart rate
- Weakness
- Vomiting
- Diarrhea
- Seizures
- Coma
What to Do:
Seek immediate medical attention or call a poison control center (1-800-222-1222). Treatment is generally supportive and symptomatic.
Drug Interactions
Moderate Interactions
- Drugs that alkalinize urine (e.g., carbonic anhydrase inhibitors, sodium bicarbonate): May decrease memantine renal clearance, leading to increased plasma levels and potential toxicity.
- NMDA antagonists (e.g., amantadine, ketamine, dextromethorphan): Co-administration may lead to increased incidence and severity of adverse reactions due to additive pharmacodynamic effects.
Minor Interactions
- Drugs eliminated by renal tubular secretion (e.g., cimetidine, ranitidine, quinidine, nicotine): Memantine is partially eliminated by tubular secretion, so co-administration with drugs that use the same renal cationic transport system could theoretically alter the plasma levels of either or both drugs.
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: To determine appropriate starting and maintenance doses, especially in patients with impaired renal function.
Timing: Prior to initiation of therapy.
Cognitive and functional assessment
Rationale: To establish baseline severity of Alzheimer's disease and monitor therapeutic response.
Timing: Prior to initiation of therapy.
Routine Monitoring
Cognitive and functional status (e.g., ADAS-Cog, MMSE, CDR-SB)
Frequency: Periodically (e.g., every 6-12 months or as clinically indicated)
Target: Stabilization or slowing of decline
Action Threshold: Significant decline or lack of benefit may warrant re-evaluation of therapy.
Adverse effects (e.g., dizziness, headache, confusion, constipation, hallucinations)
Frequency: Regularly, especially during dose titration and initiation of therapy.
Target: Tolerable side effect profile
Action Threshold: Intolerable or severe adverse effects may require dose reduction or discontinuation.
Renal function (CrCl)
Frequency: As clinically indicated, especially if there are changes in patient's renal status or concomitant medications.
Target: Stable renal function
Action Threshold: Significant decline in renal function may necessitate dose adjustment.
Symptom Monitoring
- Dizziness
- Headache
- Confusion
- Constipation
- Diarrhea
- Hallucinations
- Hypertension
- Somnolence
- Vomiting
- Agitation
Special Patient Groups
Pregnancy
Memantine is Pregnancy Category B. Animal studies have not shown evidence of teratogenicity, but there are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if clearly needed.
Trimester-Specific Risks:
First Trimester:
No increased risk of congenital anomalies observed in animal studies.
Second Trimester:
No specific risks identified.
Third Trimester:
No specific risks identified.
Lactation
It is not known whether memantine is excreted in human milk. Caution should be exercised when memantine is administered to a nursing mother. The decision to breastfeed during therapy should consider the potential for infant exposure, the benefits of breastfeeding to the infant, and the benefits of treatment to the mother.
Infant Risk:
Unknown; potential for infant exposure and adverse effects. Monitor for sedation, poor feeding, or developmental delay.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Not indicated for use in children.
Geriatric Use
No dosage adjustment is necessary based on age alone. However, dose adjustments are required for elderly patients with moderate to severe renal impairment, as renal function often declines with age.
Clinical Information
Clinical Pearls
- Memantine XR is an extended-release formulation, allowing for once-daily dosing, which can improve patient adherence compared to immediate-release formulations.
- Titration is crucial to minimize adverse effects, especially dizziness and confusion. Patients should be started on 7 mg once daily and increased weekly.
- It can be used as monotherapy or in combination with cholinesterase inhibitors (e.g., donepezil) for moderate to severe Alzheimer's disease.
- Patients should be advised not to crush or chew the capsules, as this will release the drug too quickly and could lead to higher peak plasma concentrations and increased side effects.
- Monitor for changes in urine pH, as alkaline urine can significantly reduce memantine clearance, potentially leading to toxicity. Avoid concomitant use with drugs that alkalinize urine if possible.
Alternative Therapies
- Cholinesterase inhibitors (e.g., Donepezil, Rivastigmine, Galantamine) for mild to moderate Alzheimer's disease, or in combination with memantine for moderate to severe disease.
Cost & Coverage
Average Cost:
Varies widely, typically $100-$300+ per 30 capsules (brand)
Generic Available:
Yes
Insurance Coverage:
Often Tier 2 or 3 for brand, Tier 1 for generic. Coverage varies by insurance plan.
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea 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 happened.