Namenda Tablets Titrationpak
It is used to treat dementia in people with Alzheimer's disease.
Drug Class
Agent for Alzheimer's Disease
Pharmacologic Class
N-methyl-D-aspartate (NMDA) receptor antagonist
Pregnancy Category
Category B
FDA Approved
Oct 2003
DEA Schedule
Not Controlled
Overview
What is this medicine?
Memantine is a medication used to treat moderate to severe Alzheimer's disease. It works by helping to restore the balance of certain natural substances in the brain, which can improve memory, awareness, and the ability to perform daily activities. It is not a cure for Alzheimer's, but it can help manage symptoms.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food. It's essential to continue taking your medication as prescribed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a safe place, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it 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 check if there are drug take-back programs available in your area.
What to Do If You Miss 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 to ensure it's safe to do so.
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription and follow the instructions closely. You can take this medication with or without food. It's essential to continue taking your medication as prescribed by your doctor or healthcare provider, even if you start feeling well.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a safe place, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it 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 check if there are drug take-back programs available in your area.
What to Do If You Miss 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 to ensure it's safe to do so.
Lifestyle & Tips
- Take the medication exactly as prescribed, following the titration schedule carefully.
- It can be taken with or without food.
- Do not crush, chew, or break tablets.
- Maintain a healthy lifestyle, including a balanced diet, regular exercise, and cognitive stimulation, as advised by your doctor.
- Inform your doctor about all other medications, supplements, and herbal products you are taking.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 5 mg once daily for 1 week. Week 2: 10 mg/day (5 mg twice daily). Week 3: 15 mg/day (5 mg and 10 mg once daily). Week 4 onwards: 20 mg/day (10 mg twice daily).
Dose Range:
5 - 20 mg
Condition-Specific Dosing:
Alzheimer's Disease (moderate to severe):
Titrate as described above to a target maintenance dose of 20 mg/day.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl 50-80 mL/min).
Moderate:
Maximum recommended dose is 10 mg/day (CrCl 30-49 mL/min).
Severe:
Maximum recommended dose is 5 mg/day (CrCl 5-29 mL/min).
Dialysis:
Not well studied; consider 5 mg/day with close monitoring.
Hepatic Impairment:
Mild:
No adjustment needed.
Moderate:
No adjustment needed.
Severe:
Not studied; use with caution.
Pharmacology
Mechanism of Action
Memantine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist. It binds to the NMDA receptor-operated cation channels with moderate affinity and uncompetitive kinetics, blocking the effects of abnormally high levels of glutamate, which is thought to contribute to the pathophysiology of Alzheimer's disease.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 100%
Tmax:
3-7 hours
FoodEffect:
Food does not affect the absorption of memantine.
Distribution:
Vd:
9-11 L/kg
ProteinBinding:
Approximately 45%
CnssPenetration:
Yes
Elimination:
HalfLife:
60-80 hours
Clearance:
Primarily renal clearance.
ExcretionRoute:
Urine
Unchanged:
75-80%
Pharmacodynamics
OnsetOfAction:
Gradual, due to titration schedule; clinical effects observed over weeks.
PeakEffect:
Steady-state plasma concentrations are reached within approximately 1 week of daily dosing.
DurationOfAction:
Due to long half-life, effects persist with daily dosing.
Safety & Warnings
Side Effects
Serious Side Effects: Seek Medical Help Immediately
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention right away:
- 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. Although many people do not experience side effects or only have mild 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 do not go away, contact your doctor:
- Dizziness
- Headache
- Diarrhea
- Constipation
Reporting Side Effects
This list does not include all possible side effects. If you have questions or concerns about side effects, consult your doctor for medical advice. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention right away:
- 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. Although many people do not experience side effects or only have mild 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 do not go away, contact your doctor:
- Dizziness
- Headache
- Diarrhea
- Constipation
Reporting Side Effects
This list does not include all possible side effects. If you have questions or concerns about side effects, consult your doctor for medical advice. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or lightheadedness
- Worsening confusion or agitation
- Hallucinations (seeing or hearing things that are not there)
- Seizures
- Severe skin rash or allergic reaction
- Difficulty urinating
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 identify potential interactions between this medication and other substances.
* Any existing health problems, as they may affect the safety and efficacy of this medication.
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 identify potential interactions between this medication and other substances.
* Any existing health problems, as they may affect the safety and efficacy of this medication.
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, 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:
- Agitation
- Confusion
- Hallucinations
- Stupor
- Seizures
- Coma
- Bradycardia
- Vomiting
- Hyperreflexia
- Ataxia
- Vertigo
- Aggression
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is symptomatic and supportive. Gastric lavage and activated charcoal may be considered.
Drug Interactions
Major Interactions
- Other NMDA antagonists (e.g., amantadine, ketamine, dextromethorphan): Increased risk of CNS toxicity (e.g., confusion, hallucinations, seizures).
- Drugs that increase urine pH (e.g., carbonic anhydrase inhibitors, sodium bicarbonate): Can decrease memantine renal clearance, leading to increased plasma levels and potential toxicity.
Moderate Interactions
- Anticholinergics: Potential for additive anticholinergic effects.
- Dopaminergic agonists (e.g., bromocriptine, levodopa): May enhance effects.
- Drugs eliminated by renal tubular secretion (e.g., cimetidine, ranitidine, quinidine, procainamide): May alter memantine excretion via competition for renal tubular secretion.
Monitoring
Baseline Monitoring
Renal function (e.g., serum creatinine, CrCl)
Rationale: To determine appropriate initial dosing and guide dose adjustments.
Timing: Prior to initiation of therapy.
Cognitive and functional assessment (e.g., MMSE, ADAS-Cog)
Rationale: To establish baseline cognitive status and monitor efficacy.
Timing: Prior to initiation of therapy.
Routine Monitoring
Cognitive and functional status
Frequency: Periodically (e.g., every 6-12 months or as clinically indicated)
Target: Improvement or stabilization of symptoms
Action Threshold: Significant decline in cognitive or functional status may warrant re-evaluation of therapy.
Adverse effects (e.g., dizziness, headache, confusion, constipation)
Frequency: Regularly, especially during titration and dose changes
Target: Tolerable side effect profile
Action Threshold: Persistent or severe adverse effects may require dose reduction or discontinuation.
Symptom Monitoring
- Dizziness
- Headache
- Confusion
- Constipation
- Hallucinations
- Agitation
- Fatigue
Special Patient Groups
Pregnancy
Memantine is classified as Pregnancy Category B. Animal studies have shown no evidence of teratogenicity. 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:
Risk appears low based on animal data, but human data are limited.
Second Trimester:
Risk appears low based on animal data, but human data are limited.
Third Trimester:
Risk appears low based on animal data, but human data are limited.
Lactation
Memantine is excreted in the milk of lactating rats. It is unknown whether memantine is excreted in human milk. Due to its long half-life and potential for CNS effects, caution should be exercised when memantine is administered to a nursing mother. The risk of adverse effects on the breastfed infant appears to be low.
Infant Risk:
Low risk; monitor for sedation or poor feeding.
Pediatric Use
Safety and efficacy have not been established in pediatric patients. Memantine is not indicated for use in children.
Geriatric Use
No specific dose adjustment is required based solely on age. However, dose adjustments are necessary for geriatric patients with renal impairment, as renal function commonly declines with age.
Clinical Information
Clinical Pearls
- Titration is essential to minimize common side effects like dizziness and confusion. The 'Titrationpak' is designed to facilitate this process.
- Memantine can be used as monotherapy or in combination with cholinesterase inhibitors (e.g., donepezil) for moderate to severe Alzheimer's disease.
- It is not a cure for Alzheimer's disease but may help slow the progression of symptoms and improve cognitive function.
- Patients and caregivers should be educated on the importance of adherence to the dosing schedule and monitoring for adverse effects.
- Renal function should be assessed before initiating therapy and periodically thereafter, especially in elderly patients.
Alternative Therapies
- Donepezil (Aricept)
- Rivastigmine (Exelon)
- Galantamine (Razadyne)
Cost & Coverage
Average Cost:
Varies widely; typically $50-$300 per 30 tablets (generic) or per titration pack (brand)
Generic Available:
Yes
Insurance Coverage:
Generic memantine is often covered as Tier 1 or Tier 2. Brand Namenda may be Tier 3 or higher, 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 this 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.