Mentixa (Memantine Hydrochloride)
NMDA receptor antagonist for moderate to severe Alzheimer's disease
Quick Facts About Mentixa
Key Takeaways About Mentixa
- Mentixa is an NMDA receptor antagonist: It works by regulating glutamate activity in the brain, helping to improve nerve signal transmission and memory in Alzheimer's disease
- Gradual dose increase is essential: The dose is increased weekly over 4 weeks from 5 mg to the target dose of 20 mg once daily to minimise side effects
- Used for moderate to severe Alzheimer's disease: Mentixa is specifically indicated for patients with moderate to severe stages of Alzheimer's disease, not mild dementia
- Common side effects are generally mild: Headache, drowsiness, constipation, and dizziness are the most frequently reported adverse effects
- Important drug interactions to be aware of: Avoid combining with other NMDA antagonists such as amantadine, ketamine, and dextromethorphan
What Is Mentixa and What Is It Used For?
Mentixa is a prescription medicine containing memantine hydrochloride, an NMDA receptor antagonist used for the treatment of moderate to severe Alzheimer's disease. It works by blocking excessive glutamate signalling at NMDA receptors in the brain, which helps improve nerve signal transmission and memory function.
Alzheimer's disease is a progressive neurodegenerative disorder that primarily affects memory, thinking, and behaviour. The memory loss associated with Alzheimer's disease is caused by a disturbance in message signals in the brain. The brain contains receptors known as N-methyl-D-aspartate (NMDA) receptors, which play a critical role in the transmission of nerve signals important for learning and memory. In Alzheimer's disease, there is excessive stimulation of these receptors by the neurotransmitter glutamate, which leads to nerve cell damage and cognitive decline.
Mentixa belongs to a group of medicines called NMDA receptor antagonists. It acts on these NMDA receptors by modulating the excessive glutamate activity, thereby helping to restore more normal nerve signal transmission. This mechanism of action distinguishes memantine from other Alzheimer's treatments such as cholinesterase inhibitors (donepezil, rivastigmine, galantamine), which work by a different pathway. In clinical practice, memantine may be used alone or in combination with a cholinesterase inhibitor for enhanced therapeutic benefit.
Clinical trials have demonstrated that memantine provides statistically significant benefits in cognition, global clinical impression, activities of daily living, and behaviour in patients with moderate to severe Alzheimer's disease. The European Medicines Agency (EMA) and regulatory authorities worldwide have approved memantine-based products for this indication. While Mentixa does not cure Alzheimer's disease or halt its underlying progression, it can help manage symptoms and may slow the rate of functional decline in some patients.
Memantine hydrochloride, the active ingredient in Mentixa, may also be approved for treating other conditions not mentioned in this guide. Always follow the instructions of your prescribing healthcare provider and consult them if you have any additional questions about the use of this medicine.
Memantine is one of only two classes of medication approved specifically for Alzheimer's disease. The other class, cholinesterase inhibitors, is typically used in mild to moderate disease. Memantine is the preferred choice for moderate to severe stages and may also be combined with cholinesterase inhibitors for a more comprehensive treatment approach.
What Should You Know Before Taking Mentixa?
Before starting Mentixa, your doctor needs to know about your complete medical history, including any history of epilepsy, heart disease, kidney problems, or other medications you are currently taking. Certain conditions and drug combinations require special monitoring or dose adjustments.
Contraindications
Do not use Mentixa if you are allergic (hypersensitive) to memantine hydrochloride or any of the other ingredients in this medicine. An allergic reaction may include skin rash, itching, swelling, difficulty breathing, or dizziness. If you experience any signs of an allergic reaction, stop taking the medicine and seek medical attention immediately.
You are allergic to memantine hydrochloride or any of the other ingredients listed in the composition section of this guide. If you are unsure whether you have an allergy to any of the components, consult your doctor or pharmacist before starting treatment.
Warnings and Precautions
Talk to your doctor, pharmacist, or nurse before taking Mentixa if any of the following apply to you:
- History of epileptic seizures: Memantine may lower the seizure threshold in some patients. If you have a history of epilepsy or seizures, your treatment should be carefully monitored by your doctor.
- Recent heart attack (myocardial infarction): If you have recently experienced a heart attack, your doctor will need to assess the risks and benefits of starting memantine therapy.
- Congestive heart failure: Patients with untreated or poorly controlled heart failure require close monitoring during memantine treatment.
- Uncontrolled hypertension (high blood pressure): Blood pressure should be adequately controlled before and during treatment with Mentixa.
- Kidney impairment: If you have reduced kidney function, your doctor should closely monitor your renal function and may need to adjust the dose of memantine accordingly. Significant dose reductions may be necessary in patients with moderate to severe renal impairment.
In all of the above situations, treatment should be closely supervised, and the clinical benefit of Mentixa should be regularly reassessed by your doctor. Your healthcare provider will determine the appropriate monitoring schedule based on your individual medical profile and risk factors.
The use of medicines containing amantadine (used for Parkinson's disease), ketamine (a substance generally used as an anaesthetic), dextromethorphan (generally used to treat cough), and other NMDA antagonists together with Mentixa should be avoided due to the risk of additive pharmacological effects and potential toxicity. If you are taking any of these medications, inform your doctor before starting Mentixa.
Children and Adolescents
Mentixa is not recommended for use in children and adolescents under 18 years of age. Alzheimer's disease does not occur in this age group, and the safety and efficacy of memantine have not been established in paediatric populations.
Pregnancy and Breastfeeding
If you are pregnant or breastfeeding, think you may be pregnant, or are planning to have a baby, ask your doctor for advice before taking this medicine. The use of memantine in pregnant women is not recommended due to insufficient data on its safety during pregnancy. Animal studies have provided limited information about the potential effects on fetal development, and the precautionary principle applies.
Women who are taking Mentixa should not breastfeed. It is not known whether memantine is excreted in human breast milk, but given its pharmacological properties, a risk to the nursing infant cannot be excluded. Your doctor will help you weigh the benefits of treatment against the potential risks to decide the best course of action.
Driving and Using Machines
Your doctor will advise you whether your condition allows you to drive safely and use machinery. Mentixa may also affect your reaction time, making it inadvisable to drive or operate machinery in some cases. Additionally, Alzheimer's disease itself commonly impairs the ability to drive and operate complex equipment. You are personally responsible for assessing whether you are in a fit condition to drive or perform tasks requiring mental alertness. The effects and side effects of this medicine are described in other sections of this guide and should be carefully considered.
Mentixa contains lactose. If you have been told by your doctor that you have an intolerance to certain sugars, contact your doctor before taking this medicine. This medicine also contains less than 1 mmol (23 mg) sodium per tablet, meaning it is essentially sodium-free.
How Does Mentixa Interact with Other Drugs?
Mentixa can interact with several types of medication, including other NMDA antagonists, muscle relaxants, urinary alkalising agents, and various central nervous system drugs. Always inform your doctor about all medicines you are taking, including over-the-counter products and herbal supplements.
Drug interactions can change the way your medicines work or increase the risk of serious side effects. Tell your doctor or pharmacist about all the medicines you are taking, have recently taken, or might take. This is especially important because memantine is primarily eliminated by the kidneys, and any medication that affects kidney function or urinary pH can potentially alter memantine levels in the body.
Major Interactions
The following medicines may particularly affect the effects of Mentixa, and their doses may need to be adjusted by your doctor:
| Drug / Drug Class | Interaction Type | Clinical Significance |
|---|---|---|
| Amantadine | Pharmacodynamic — both are NMDA antagonists | Avoid combination; risk of CNS adverse effects including psychosis and confusion |
| Ketamine | Pharmacodynamic — NMDA antagonist | Avoid combination; enhanced NMDA blockade may cause CNS toxicity |
| Dextromethorphan | Pharmacodynamic — NMDA antagonist activity | Avoid combination; found in many over-the-counter cough medicines |
| Dantrolene / Baclofen | Pharmacodynamic — CNS effects | Dose adjustment may be needed; monitor for enhanced sedation |
| Hydrochlorothiazide | Pharmacokinetic — reduced renal clearance of memantine | May increase memantine levels; monitor for adverse effects |
| Cimetidine / Ranitidine | Pharmacokinetic — renal tubular secretion | May increase memantine levels; clinical monitoring recommended |
| Anticholinergics | Pharmacodynamic — enhanced anticholinergic effects | Monitor for increased anticholinergic side effects (dry mouth, constipation, urinary retention) |
| Antiepileptics (barbiturates) | Pharmacodynamic — CNS depression | Dose adjustments may be necessary; enhanced sedation possible |
| Dopaminergic agonists (L-dopa, bromocriptine) | Pharmacodynamic — enhanced dopaminergic effects | Effects of dopaminergic agonists may be enhanced |
| Oral anticoagulants (warfarin) | Possible pharmacodynamic interaction | Monitor INR closely; dose adjustments of anticoagulant may be needed |
| Neuroleptics | Pharmacodynamic — altered CNS effects | Effects of neuroleptics may be altered; monitor for changes in efficacy or side effects |
| Procainamide / Quinidine / Quinine / Nicotine | Pharmacokinetic — share renal cationic transport system | May affect memantine plasma levels; clinical monitoring advised |
Dietary and Lifestyle Considerations
You should inform your doctor if you have recently changed or intend to significantly change your diet (for example, switching from a normal diet to a strict vegetarian diet), or if you suffer from conditions of renal tubular acidosis (RTA) or severe urinary tract infections. These situations can alter the pH of your urine, which in turn can affect how memantine is eliminated from your body. Your doctor may need to adjust your dose accordingly.
If you are admitted to hospital for any reason, make sure to tell the treating medical team that you are taking Mentixa. This information is important because memantine can interact with anaesthetics and other hospital medicines, and appropriate precautions may need to be taken during your care.
Mentixa tablets can be taken with or without food. However, significant dietary changes that alter urinary pH may affect how the medicine is processed by your body. Regarding alcohol, while no specific interaction studies have been conducted, patients with Alzheimer's disease are generally advised to limit alcohol consumption as it can worsen cognitive symptoms.
What Is the Correct Dosage of Mentixa?
The recommended target dose of Mentixa is 20 mg once daily. To reduce the risk of side effects, the dose is gradually increased over 4 weeks, starting at 5 mg daily in the first week and increasing by 5 mg each week until the maintenance dose of 20 mg daily is reached.
Always take this medicine exactly as your doctor has told you. Check with your doctor or pharmacist if you are not sure about the correct dose. Mentixa should be taken orally once a day at the same time each day. The tablets should be swallowed with some water and can be taken with or without food. The 10 mg tablet can be divided into two equal doses.
Adults and Elderly Patients
The recommended maintenance dose of Mentixa for adults and elderly patients is 20 mg once daily. To minimise the risk of adverse effects, this dose is achieved gradually through the following daily treatment schedule:
| Week | Daily Dose | How to Take |
|---|---|---|
| Week 1 | 5 mg | Half a 10 mg tablet once daily |
| Week 2 | 10 mg | One 10 mg tablet once daily |
| Week 3 | 15 mg | One and a half 10 mg tablets once daily |
| Week 4 onwards | 20 mg | Two 10 mg tablets or one 20 mg tablet once daily |
It is critical that the titration schedule is followed precisely. Jumping to the full dose too quickly can increase the risk of adverse effects such as dizziness, headache, and confusion. Your doctor may decide to keep you at a lower dose if you are experiencing significant side effects during the titration phase.
Children and Adolescents
Mentixa is not recommended for use in children and adolescents under 18 years of age. Alzheimer's disease does not occur in paediatric populations, and the safety and efficacy of memantine have not been studied in this age group.
Patients with Kidney Impairment
If you have impaired kidney function, your doctor will determine a dose that suits your condition. In cases of moderate renal impairment (creatinine clearance 30–49 mL/min), the maintenance dose is typically reduced to 10 mg once daily. In severe renal impairment (creatinine clearance 5–29 mL/min), the dose may be further reduced to 10 mg once daily, and your doctor should monitor your kidney function at specified intervals to ensure the medicine is being safely processed by your body.
Missed Dose
If you discover that you have forgotten to take your dose of Mentixa, wait and take your next dose at the usual time. Do not take a double dose to make up for a forgotten dose. Taking extra memantine will not provide additional benefit and may increase the risk of side effects. If you frequently forget to take your medicine, consider using a pill organiser or setting a daily alarm as a reminder.
Overdose
In general, taking too much Mentixa should not be harmful, but you may experience increased symptoms as described in the side effects section of this guide. If you take a large overdose of Mentixa, contact your doctor or seek medical advice immediately, as you may need medical care. Symptoms of significant overdose may include restlessness, psychosis, visual hallucinations, drowsiness, stupor, and loss of consciousness.
Continue taking Mentixa for as long as your doctor has instructed. Your doctor should regularly reassess the benefits of your treatment. Do not stop taking Mentixa without consulting your doctor first, as abrupt discontinuation may lead to a worsening of symptoms. Treatment duration is individualised and should be reviewed periodically to ensure continued clinical benefit.
What Are the Side Effects of Mentixa?
Like all medicines, Mentixa can cause side effects, although not everybody gets them. In general, the observed side effects are mild to moderate. The most commonly reported adverse effects include headache, drowsiness, constipation, dizziness, and elevated liver function tests.
Side effects are classified by how frequently they occur. Understanding these frequencies can help you and your healthcare provider make informed decisions about your treatment and know what to watch for during therapy.
Common
May affect up to 1 in 10 people
- Headache
- Drowsiness (somnolence)
- Constipation
- Elevated liver function tests
- Dizziness
- Balance disorders
- Shortness of breath (dyspnoea)
- High blood pressure (hypertension)
- Drug hypersensitivity
Uncommon
May affect up to 1 in 100 people
- Fatigue
- Fungal infections
- Confusion
- Hallucinations
- Vomiting
- Gait disturbances (abnormal walking)
- Heart failure
- Blood clots in veins (venous thrombosis/thromboembolism)
Very Rare
May affect up to 1 in 10,000 people
- Seizures (convulsions)
Frequency Not Known
Cannot be estimated from available data
- Pancreatitis (inflammation of the pancreas)
- Hepatitis (inflammation of the liver)
- Psychotic reactions
Alzheimer's disease has been associated with depression, suicidal thoughts, and suicide. These events have been reported in patients treated with memantine. If you or your caregiver notice any changes in mood, increased depression, or thoughts of self-harm, contact your doctor immediately. These symptoms should be taken seriously and assessed promptly regardless of whether they are thought to be related to the medication or the underlying disease.
Most side effects are mild to moderate in severity and tend to occur more frequently during the dose titration phase. If you experience any side effects that are bothersome, persistent, or concerning, talk to your doctor or pharmacist. They may be able to suggest strategies to manage the side effects or adjust your treatment accordingly.
It is important to report suspected side effects after a medicine has been authorised. This makes it possible to continuously monitor the benefit-risk balance of the medicine. Healthcare professionals and patients are encouraged to report any suspected adverse reactions to their national medicines regulatory authority.
How Should You Store Mentixa?
Keep Mentixa out of sight and reach of children. Do not use the medicine after the expiry date shown on the carton and blister pack. Blister-packed tablets have no special storage requirements. Bottles should be stored below 25°C after opening and used within 3 months.
Proper storage of medicines is important to ensure they remain effective and safe to use throughout their shelf life. The following storage guidelines apply to Mentixa:
- Keep out of sight and reach of children: Store all medicines in a secure location that children cannot access. Consider using a locked medicine cabinet if children are present in the household.
- Check the expiry date: Do not use this medicine after the expiry date (EXP) printed on the carton and blister pack. The expiry date refers to the last day of the stated month.
- Blister packs: No special storage conditions are required for Mentixa in blister packaging. Store at room temperature, away from excessive heat and moisture.
- Tablet bottles: After first opening the bottle, the contents should be used within 3 months. Store below 25°C (77°F). Keep the bottle tightly closed to protect from moisture.
- Disposal: Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. These measures help to protect the environment.
If you notice any changes in the appearance of the tablets (discolouration, crumbling, unusual odour), do not take them and consult your pharmacist. Always check that the packaging is intact before use, and never transfer tablets to containers that lack proper labelling.
What Does Mentixa Contain?
Mentixa film-coated tablets contain the active substance memantine hydrochloride. The 10 mg tablet contains 10 mg memantine hydrochloride (equivalent to 8.31 mg memantine), and the 20 mg tablet contains 20 mg memantine hydrochloride (equivalent to 16.62 mg memantine).
Active Ingredient
The active substance is memantine hydrochloride:
- 10 mg tablets: Each film-coated tablet contains 10 mg memantine hydrochloride, equivalent to 8.31 mg memantine base
- 20 mg tablets: Each film-coated tablet contains 20 mg memantine hydrochloride, equivalent to 16.62 mg memantine base
Inactive Ingredients (Excipients)
The other ingredients are:
- Tablet core: Lactose monohydrate, microcrystalline cellulose (E460), colloidal anhydrous silica, talc (E553b), and magnesium stearate (E470b)
- Film coating: Methacrylic acid-ethyl acrylate copolymer (1:1), sodium lauryl sulphate, polysorbate 80, talc (E553b), triacetin, and simethicone emulsion (containing dimethicone, colloidal hydrated silica, macrogol stearyl ether, hydrogen peroxide, sorbic acid, and water)
Appearance and Pack Sizes
10 mg tablets: White, oval, biconvex film-coated tablets with a score line on one side (tablet length: 12.2–12.9 mm, thickness: 3.5–4.5 mm). The tablets can be divided into two equal doses.
20 mg tablets: White, oval, biconvex film-coated tablets (tablet length: 15.7–16.4 mm, thickness: 4.7–5.7 mm).
Mentixa is available in blister packs of 14, 28, 30, 42, 50, 56, 60, 70, 84, 90, 98, 100, and 112 film-coated tablets, as well as in tablet bottles of 100 film-coated tablets with a tamper-evident seal. Not all pack sizes may be marketed in all countries.
Frequently Asked Questions About Mentixa
References and Sources
This article is based on international medical guidelines, regulatory documents, and peer-reviewed research. All medical claims are supported by evidence level 1A, the highest quality of evidence.
- European Medicines Agency (EMA). Memantine Summary of Product Characteristics. EMA, 2024. Available from the EMA product database.
- World Health Organization (WHO). WHO Model List of Essential Medicines — 23rd List. WHO, 2023.
- National Institute for Health and Care Excellence (NICE). Dementia: assessment, management and support for people living with dementia and their carers. NICE guideline [NG97], updated 2023.
- Reisberg B, Doody R, Stöffler A, Schmitt F, Ferris S, Möbius HJ. Memantine in moderate-to-severe Alzheimer's disease. N Engl J Med. 2003;348(14):1333–1341.
- McShane R, Westby MJ, Roberts E, et al. Memantine for dementia. Cochrane Database Syst Rev. 2019;3(3):CD003154.
- Cummings J, Lee G, Nahed P, et al. Alzheimer's disease drug development pipeline: 2024. Alzheimers Dement (N Y). 2024;10(1):e12465.
- British National Formulary (BNF). Memantine hydrochloride. NICE Evidence Services, 2024.
- Alzheimer's Association. Medications for Memory, Cognition and Dementia-Related Behaviors. Alzheimer's Association, 2024.
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