Memantine ER 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 ER 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 learning. It may help improve memory, awareness, and the ability to perform daily activities.
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 capsules that appear abnormal or are damaged, 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 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 with your pharmacist for guidance on the best disposal method. You may also want to explore drug take-back programs in your area.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take 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 capsules that appear abnormal or are damaged, 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 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 with your pharmacist for guidance on the best disposal method. You may also want to explore drug take-back programs in your area.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take 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. It can be taken with or without food.
- If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take two doses at once.
- Store at room temperature, away from moisture and heat.
- Continue with other prescribed treatments and therapies for Alzheimer's disease as directed by your doctor.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
28 mg once daily
Dose Range:
7 - 28 mg
Condition-Specific Dosing:
Alzheimer's Disease (moderate to severe):
Initial: 7 mg once daily. Titrate weekly by 7 mg increments to target dose of 28 mg once daily. Swallow capsule whole; do not chew or crush. Can be taken with or without food.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No dose adjustment necessary (CrCl 50-80 mL/min)
Moderate:
Maximum dose 14 mg once daily (CrCl 30-49 mL/min)
Severe:
Maximum dose 14 mg once daily (CrCl 5-29 mL/min)
Dialysis:
Not recommended due to limited data; if used, consider maximum 7 mg once daily with close monitoring.
Hepatic Impairment:
Mild:
No dose adjustment necessary
Moderate:
No dose adjustment necessary
Severe:
Use with caution; not studied in severe hepatic impairment.
Pharmacology
Mechanism of Action
Memantine is a non-competitive antagonist of N-methyl-D-aspartate (NMDA) receptors. It binds to the NMDA receptor-operated cation channels with moderate affinity and voltage-dependency. It is thought to protect neurons from excitotoxic damage caused by pathologically elevated tonic levels of glutamate, which may contribute to the symptoms of Alzheimer's disease, without interfering with the physiological activation of NMDA receptors essential for normal neuronal function.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 100%
Tmax:
9-12 hours (for extended-release formulation)
FoodEffect:
No significant effect of food on absorption.
Distribution:
Vd:
9-11 L/kg
ProteinBinding:
Approximately 45%
CnssPenetration:
Yes
Elimination:
HalfLife:
60-80 hours (for extended-release formulation)
Clearance:
Renal clearance is the primary route of elimination.
ExcretionRoute:
Renal (urine)
Unchanged:
75-90%
Pharmacodynamics
OnsetOfAction:
Not precisely defined for clinical effect in Alzheimer's; therapeutic effects are gradual.
PeakEffect:
Not precisely defined for clinical effect; steady-state concentrations are reached within approximately 7-14 days.
DurationOfAction:
Due to long half-life, once-daily dosing provides sustained therapeutic levels.
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. Immediately contact your doctor or seek medical attention if you experience any of the following symptoms, which may indicate a serious allergic reaction:
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
Confusion
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they persist or bother you:
Dizziness
Headache
Diarrhea
Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. 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.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. Immediately contact your doctor or seek medical attention if you experience any of the following symptoms, which may indicate a serious allergic reaction:
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
Confusion
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they persist or bother you:
Dizziness
Headache
Diarrhea
Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. 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 lightheadedness
- New or worsening confusion or hallucinations
- Difficulty urinating or changes in urination
- Unusual tiredness or weakness
- Severe headache
- 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.
Potential interactions with other medications or health conditions. This medication may affect or be affected by other drugs or health problems, so it is crucial to disclose all relevant information.
To ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products, such as herbal supplements
Vitamins
Any existing health problems
Carefully review your medication regimen and health status with your doctor to confirm that it is safe to take this medication in combination with your other drugs and health conditions. Do not initiate, discontinue, or modify 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.
Potential interactions with other medications or health conditions. This medication may affect or be affected by other drugs or health problems, so it is crucial to disclose all relevant information.
To ensure safe treatment, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products, such as herbal supplements
Vitamins
Any existing health problems
Carefully review your medication regimen and health status with your doctor to confirm that it is safe to take this medication in combination with your other drugs and health conditions. Do not initiate, discontinue, or modify 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, you must discuss this with your doctor. This conversation will help you understand the potential benefits and risks of this medication to both you and your baby, allowing you to make an informed decision.
Overdose Information
Overdose Symptoms:
- Severe dizziness
- Agitation
- Confusion
- Hallucinations
- Seizures
- Slowed heart rate
- Vomiting
- Unconsciousness
What to Do:
Seek immediate medical attention or call a Poison Control Center (1-800-222-1222). Treatment is supportive and symptomatic.
Drug Interactions
Major Interactions
- Other NMDA antagonists (e.g., amantadine, ketamine, dextromethorphan): Concomitant use may increase the frequency and severity of adverse reactions, primarily CNS-related (e.g., confusion, hallucinations, dizziness).
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.
- Hydrochlorothiazide (HCTZ): Co-administration may lead to a reduction in memantine plasma levels.
- Cimetidine, Ranitidine, Quinidine, Nicotine: May affect memantine excretion, though clinical significance is generally minor.
Minor Interactions
- Anticholinergics: Potential for increased anticholinergic effects.
- Dopaminergic agonists (e.g., bromocriptine, levodopa): Potential for decreased effects of dopaminergic agonists.
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: Memantine is primarily renally eliminated; dose adjustment is required in patients with moderate to severe renal impairment.
Timing: Prior to initiation of therapy.
Routine Monitoring
Cognitive and functional status
Frequency: Periodically, as clinically indicated (e.g., every 3-6 months)
Target: Stabilization or improvement in symptoms of Alzheimer's disease.
Action Threshold: Significant decline or lack of benefit may warrant re-evaluation of therapy.
Blood pressure
Frequency: Periodically, as clinically indicated
Target: Within normal limits for the patient.
Action Threshold: Significant or persistent hypertension may require intervention or re-evaluation of therapy.
Symptom Monitoring
- Dizziness
- Headache
- Confusion
- Hallucinations
- Constipation
- Diarrhea
- Hypertension
- Somnolence
- Agitation
Special Patient Groups
Pregnancy
Memantine is Pregnancy Category B. Animal studies have not shown evidence of harm to the fetus. There are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if clearly needed.
Trimester-Specific Risks:
First Trimester:
Low risk based on animal data; human data limited.
Second Trimester:
Low risk based on animal data; human data limited.
Third Trimester:
Low risk based on animal data; human data limited.
Lactation
Memantine is excreted in breast milk. The amount of memantine transferred to breast milk is unknown, but due to its long half-life and potential for CNS effects in the infant, caution is advised. The decision to breastfeed should consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for memantine and any potential adverse effects on the breastfed infant.
Infant Risk:
L3 (Moderate risk) - Potential for CNS effects (e.g., sedation, irritability) in the infant. Monitor infant for adverse effects.
Pediatric Use
Safety and effectiveness have not been established in pediatric patients. Not indicated for use in this population.
Geriatric Use
No specific dose adjustment is required based on age alone. However, elderly patients are more likely to have decreased renal function, which necessitates dose adjustment based on creatinine clearance.
Clinical Information
Clinical Pearls
- Memantine ER is typically initiated at a low dose and gradually titrated up to the target dose to improve tolerability and minimize side effects like dizziness.
- It can be taken with or without food, but consistency in administration (e.g., always with breakfast) may help adherence.
- Unlike cholinesterase inhibitors, memantine is an NMDA receptor antagonist and can be used alone or in combination with cholinesterase inhibitors for moderate to severe Alzheimer's disease.
- Patients or caregivers should be educated on the importance of swallowing the capsule whole and not crushing or chewing it, as this would alter the extended-release properties.
- Monitor for changes in behavior, mood, or cognitive function, as well as common side effects like dizziness, headache, and confusion.
Alternative Therapies
- Donepezil (Aricept)
- Rivastigmine (Exelon)
- Galantamine (Razadyne)
Cost & Coverage
Average Cost:
Varies widely, typically $100-$300 per 30 capsules (28mg)
Generic Available:
Yes
Insurance Coverage:
Most insurance plans cover generic memantine ER, often as a Tier 1 or Tier 2 medication. Brand-name Namenda XR may be Tier 3 or require 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 happened.