Memantine 2mg/ml Solution
It is used to treat dementia in people with Alzheimer's disease.
Drug Class
Anti-Alzheimer's agent
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 affecting certain chemicals in the brain that are involved in memory and learning, helping to improve thinking, memory, and the ability to perform daily activities.
How to Use This Medicine
Taking Your Medication Correctly
To ensure you get the most benefit from your medication, follow these steps:
Take your medication exactly as directed by your doctor. Read all the information provided with your medication and follow the instructions carefully.
You can take this medication with or without food.
Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel well.
When taking the liquid form of this medication, measure your dose carefully using the measuring device provided with the medication. Do not mix the medication with any other liquid.
Storing and Disposing of Your Medication
To keep your medication safe and effective:
Store your medication at room temperature in a dry place, away from the bathroom.
Keep all medications in a secure location, out of the reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. Check with your pharmacist for guidance on the best way to dispose of your medication. You may also want to explore drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose of your medication:
Skip the missed dose 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 you get the most benefit from your medication, follow these steps:
Take your medication exactly as directed by your doctor. Read all the information provided with your medication and follow the instructions carefully.
You can take this medication with or without food.
Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel well.
When taking the liquid form of this medication, measure your dose carefully using the measuring device provided with the medication. Do not mix the medication with any other liquid.
Storing and Disposing of Your Medication
To keep your medication safe and effective:
Store your medication at room temperature in a dry place, away from the bathroom.
Keep all medications in a secure location, out of the reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. Check with your pharmacist for guidance on the best way to dispose of your medication. You may also want to explore drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose of your medication:
Skip the missed dose 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.
Lifestyle & Tips
- Take exactly as prescribed, usually once or twice daily.
- Do not stop taking memantine suddenly without consulting your doctor, as this may worsen symptoms.
- Maintain adequate hydration.
- Report any new or worsening side effects to your healthcare provider.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 5 mg once daily. Increase by 5 mg/day weekly to a target dose of 10 mg twice daily (20 mg/day total).
Dose Range:
5 - 20 mg
Condition-Specific Dosing:
moderateToSevereAlzheimersDisease:
Initial: 5 mg once daily. Titrate weekly by 5 mg/day increments to a target dose of 10 mg twice daily (20 mg/day total).
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No dosage 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; generally, a maximum of 5 mg/day is recommended, or avoid use if possible.
Hepatic Impairment:
Mild:
No dosage adjustment needed.
Moderate:
No dosage adjustment needed.
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 blocks the effects of pathologically elevated tonic levels of glutamate, which may lead to neuronal dysfunction.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 100%
Tmax:
3-7 hours
FoodEffect:
Minimal effect on absorption
Distribution:
Vd:
9-11 L/kg
ProteinBinding:
Approximately 45%
CnssPenetration:
Yes
Elimination:
HalfLife:
60-80 hours
Clearance:
Primarily renal clearance
ExcretionRoute:
Renal
Unchanged:
Approximately 48% (renal excretion)
Pharmacodynamics
OnsetOfAction:
Days to weeks (due to slow titration and long half-life)
PeakEffect:
Weeks (after reaching target dose)
DurationOfAction:
Continuous with daily dosing due to long half-life
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
If you experience any of the following symptoms, call your doctor or seek medical attention immediately, as they may be signs of a severe and potentially life-threatening reaction:
- 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, or 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. Contact your doctor if you experience any of the following side effects or if they persist or bother you:
- Dizziness or headache
- Diarrhea or 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 about side effects, you can also contact your doctor. Additionally, you can report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
If you experience any of the following symptoms, call your doctor or seek medical attention immediately, as they may be signs of a severe and potentially life-threatening reaction:
- 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, or 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. Contact your doctor if you experience any of the following side effects or if they persist or bother you:
- Dizziness or headache
- Diarrhea or 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 about side effects, you can also contact your doctor. Additionally, you can 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
- New or worsening confusion or agitation
- Seizures
- Severe skin rash or allergic reaction
- Difficulty breathing or swallowing
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.
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.
* Any existing health problems, as this medication may interact with them.
To ensure your safety, carefully review all your medications and health conditions with your doctor and pharmacist. Do not start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm it is safe to do so.
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.
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.
* Any existing health problems, as this medication may interact with them.
To ensure your safety, carefully review all your medications and health conditions with your doctor and pharmacist. Do not start, stop, or adjust the dosage of any medication without first consulting your doctor to confirm it is safe to do so.
Precautions & Cautions
It is essential to inform all of 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, 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
- Dizziness
- Stupor
- Seizures
- Coma
- Bradycardia
- Vertigo
- Vomiting
- Diarrhea
What to Do:
Seek immediate medical attention. Call 911 or a poison control center (1-800-222-1222). Treatment is supportive and symptomatic. There is no specific antidote.
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.
- NMDA antagonists (e.g., amantadine, ketamine, dextromethorphan): Concomitant use may lead to increased incidence or severity of CNS adverse reactions.
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: To determine appropriate initial and maintenance dosing, especially in patients with impaired renal function.
Timing: Prior to initiation of therapy
Routine Monitoring
Clinical response (cognitive and functional status)
Frequency: Periodically, as clinically indicated
Target: Improvement or stabilization of symptoms of Alzheimer's disease
Action Threshold: Lack of efficacy or worsening symptoms may warrant re-evaluation of treatment plan.
Adverse effects (e.g., dizziness, headache, confusion, constipation, hallucinations)
Frequency: Regularly, especially during dose titration
Target: Tolerable side effect profile
Action Threshold: Intolerable side effects may require dose reduction or discontinuation.
Symptom Monitoring
- Dizziness
- Headache
- Confusion
- Constipation
- Hallucinations
- Agitation
- Fatigue
- Vomiting
Special Patient Groups
Pregnancy
Category B. Animal studies have not shown harm to the fetus, but there are no adequate and well-controlled studies in pregnant women. Use only if clearly needed.
Trimester-Specific Risks:
First Trimester:
Limited human data, animal studies show no evidence of teratogenicity.
Second Trimester:
Limited human data.
Third Trimester:
Limited human data.
Lactation
Memantine is excreted in breast milk. Due to the potential for serious adverse reactions in the breastfed infant, 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:
Moderate risk (L3). Potential for CNS effects in the infant due to long half-life and excretion into milk.
Pediatric Use
Safety and effectiveness have not been established in pediatric patients. Not indicated for use in children.
Geriatric Use
Memantine is primarily used in the geriatric population. Dosage adjustments are necessary for elderly patients with renal impairment.
Clinical Information
Clinical Pearls
- Titrate the dose slowly over several weeks to minimize gastrointestinal and CNS side effects (e.g., dizziness, confusion).
- Can be administered with or without food.
- Memantine can be used concomitantly with cholinesterase inhibitors (e.g., donepezil) for moderate to severe Alzheimer's disease.
- Patients should be advised not to abruptly discontinue memantine, as this may lead to worsening of symptoms.
- The oral solution can be administered directly or mixed with a small amount of food (e.g., applesauce, yogurt).
Alternative Therapies
- Donepezil (Aricept) - Cholinesterase inhibitor
- Rivastigmine (Exelon) - Cholinesterase inhibitor
- Galantamine (Razadyne) - Cholinesterase inhibitor
Cost & Coverage
Average Cost:
$30-$100 per 30 ml (2mg/ml) bottle
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is 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 it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with 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 detailed information about the overdose, including the medication taken, the amount, and the time it occurred.