Ebixa (Memantine)

What Is Ebixa and What Is It Used For?

Ebixa contains memantine hydrochloride and belongs to a group of medicines known as anti-dementia drugs. It is used to treat patients with moderate to severe Alzheimer’s disease. Memantine acts on NMDA receptors in the brain to improve nerve signal transmission involved in learning and memory.

Alzheimer’s disease is a progressive neurodegenerative disorder that causes memory loss, cognitive decline, and difficulty performing everyday activities. It is the most common cause of dementia, affecting an estimated 55 million people worldwide according to the World Health Organization (WHO). The disease is characterised by the accumulation of abnormal protein deposits in the brain, including amyloid plaques and neurofibrillary tangles, which lead to the death of nerve cells and a progressive shrinkage of brain tissue.

In a healthy brain, the neurotransmitter glutamate plays a crucial role in learning and memory by activating NMDA (N-methyl-D-aspartate) receptors on nerve cells. In Alzheimer’s disease, however, there is an abnormal and sustained increase in glutamate levels. This chronic overstimulation of NMDA receptors, known as excitotoxicity, damages nerve cells and impairs normal signal transmission. The result is a progressive loss of the brain’s ability to form new memories and process information.

Memantine is a voltage-dependent, moderate-affinity, uncompetitive NMDA receptor antagonist. It works by selectively blocking the excessive glutamate signalling that causes neuronal damage, while still allowing the normal, transient activation of NMDA receptors that is necessary for learning and memory. This dual action – blocking pathological overstimulation whilst preserving physiological signalling – is what distinguishes memantine from other NMDA receptor blockers such as ketamine, which block the receptor more completely and cannot be used therapeutically for dementia.

Ebixa is specifically approved for the treatment of moderate to severe Alzheimer’s disease. Clinical trials have demonstrated that memantine can improve cognition, global function, and the ability to perform activities of daily living in patients with moderate to severe disease. It is important to note that memantine does not cure Alzheimer’s disease or halt the underlying neurodegenerative process, but it may slow the rate of clinical deterioration and help patients maintain independence for longer.

What Should You Know Before Taking Ebixa?

Before starting Ebixa, tell your doctor about all your medical conditions, especially epilepsy, recent heart attack, heart failure, high blood pressure, or kidney problems. Inform your doctor about all other medications you are taking, as several drug interactions can occur.

Contraindications

You should not take Ebixa if you are allergic to memantine hydrochloride or any of the other ingredients in the medication. Signs of an allergic reaction may include skin rash, itching, swelling of the face or throat, or difficulty breathing. If you experience any of these symptoms, stop taking Ebixa and seek immediate medical attention.

Warnings and Precautions

Talk to your doctor or pharmacist before taking Ebixa if you have or have had any of the following conditions:

• Epilepsy or a history of seizures – memantine may lower the seizure threshold in susceptible individuals, and your doctor will need to weigh the benefits against the risks
• Recent myocardial infarction (heart attack) – extra monitoring may be needed during the initial phase of treatment
• Uncontrolled heart failure – your doctor should carefully monitor your cardiovascular status during treatment
• Uncontrolled hypertension (high blood pressure) – memantine may occasionally elevate blood pressure, so regular monitoring is advisable
• Kidney impairment – memantine is primarily excreted by the kidneys, and your doctor may need to adjust the dose or monitor kidney function at regular intervals if you have reduced kidney function
• Renal tubular acidosis (RTA) – an excess of acid-forming substances in the blood due to kidney dysfunction may require dose adjustment
• Severe urinary tract infections – conditions that significantly alter the pH of urine can affect how memantine is excreted, potentially requiring dose modification

In all of the above situations, treatment should be closely monitored and the clinical benefit of Ebixa should be regularly reassessed by your doctor. If there is no meaningful improvement or if symptoms worsen, your doctor may decide to discontinue the treatment.

Concurrent Use of Other NMDA Antagonists

The concurrent use of other medications that act on NMDA receptors should be avoided. These include:

• Amantadine – used to treat Parkinson’s disease and influenza
• Ketamine – a substance generally used as an anaesthetic
• Dextromethorphan – commonly found in over-the-counter cough medications

Using memantine alongside these drugs may increase the risk of central nervous system side effects, including confusion, hallucinations, dizziness, and psychomotor disturbances. Always inform your doctor about all medications you are taking, including over-the-counter products and herbal supplements.

Children and Adolescents

Ebixa 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

The use of memantine during pregnancy is not recommended unless clearly necessary. There are limited data on the use of memantine in pregnant women, and animal studies are insufficient to fully assess the potential risks to the developing foetus. If you are pregnant, think you might be pregnant, or are planning to become pregnant, you should consult your doctor before taking Ebixa.

Women taking Ebixa should not breastfeed. It is not known whether memantine passes into human breast milk, but based on the chemical properties of the drug (its lipophilicity), excretion into breast milk is considered likely. Your doctor will advise you on the best approach if you are breastfeeding or planning to breastfeed.

Driving and Operating Machinery

Your doctor will advise you whether your illness allows you to drive and operate machinery safely. Additionally, Ebixa itself may alter your reaction time, making driving or operating machinery potentially unsafe. Moderate to severe Alzheimer’s disease usually causes significant impairment of driving performance and these activities, so this should be discussed with your healthcare provider on a case-by-case basis.

Food, Drink, and Diet

Ebixa can be taken with or without food. However, you should tell your doctor if you have recently changed or intend to significantly change your diet (for example, from a regular diet to a strict vegetarian diet). Significant dietary changes can alter urinary pH, which may affect how memantine is excreted by the kidneys. Your doctor may need to adjust your dose accordingly.

Sodium Content

Ebixa film-coated tablets contain less than 1 mmol (23 mg) sodium per tablet, meaning they are essentially “sodium-free”. This is relevant for patients on a sodium-restricted diet.

How Does Ebixa Interact with Other Drugs?

Ebixa can interact with several medications, including other NMDA antagonists, dopaminergic agents, barbiturates, antiepileptics, and drugs that alter urinary pH. Always tell your doctor about all medications you are currently taking or have recently taken.

Memantine is not metabolised by the cytochrome P450 (CYP) enzyme system, which reduces its potential for interactions with drugs metabolised by these enzymes. However, memantine is primarily excreted unchanged by the kidneys, and drugs that share the same renal transport mechanisms or that alter urinary pH can affect memantine blood levels. The following tables summarise the most clinically important interactions.

Major Interactions

Moderate Interactions

Memantine can be safely combined with cholinesterase inhibitors such as donepezil, rivastigmine, and galantamine. In fact, combination therapy is commonly used and recommended in clinical guidelines for moderate to severe Alzheimer’s disease. There is no clinically significant pharmacokinetic interaction between memantine and these drugs.

If you are admitted to hospital for any reason, you should inform the medical team that you are taking Ebixa, as the medication may interact with anaesthetics or other drugs used during surgical or diagnostic procedures.

What Is the Correct Dosage of Ebixa?

The recommended maintenance dose is 20 mg once daily, reached through a gradual dose increase over the first 3 weeks. Treatment starts at 5 mg/day in week 1, increases to 10 mg/day in week 2, 15 mg/day in week 3, and 20 mg/day from week 4 onward. A starter pack is available to facilitate this titration.

Always take Ebixa exactly as your doctor has told you. Do not change your dose without consulting your doctor first. The dose must be increased gradually during the first weeks to reduce the risk of side effects. A special starter pack containing all four tablet strengths is available to simplify the titration process.

Adults – Standard Titration

Patients with Kidney Impairment

If you have kidney impairment, your doctor will decide on a dose suitable for your condition. Kidney function should be monitored at regular intervals throughout treatment. In patients with moderate renal impairment (creatinine clearance 30–49 ml/min), the maintenance dose is typically 10 mg once daily. If well tolerated after at least 7 days, the dose may be increased to 20 mg/day using the standard titration schedule. In severe renal impairment (creatinine clearance 5–29 ml/min), the recommended maintenance dose is 10 mg once daily.

How to Take Ebixa

Ebixa should be taken orally once daily, at the same time each day. The tablets should be swallowed with a glass of water. They can be taken with or without food. To get the full benefit of the medication, you must take it regularly every day. If using the oral solution, follow the instructions provided with the dosing pump – each pump actuation delivers 0.5 ml (5 mg memantine). The solution can be taken directly or mixed with a small amount of water.

Missed Dose

If you forget to take your dose of Ebixa, wait and take your next dose at the usual time. Do not take a double dose to make up for the forgotten one. If you are a caregiver administering the medication, it may be helpful to establish a consistent daily routine or use a pill organiser to ensure doses are not missed.

Overdose

Duration of Treatment

Continue taking Ebixa for as long as you benefit from it. Your doctor should regularly reassess your treatment, typically every 3–6 months, to determine whether continued use is appropriate. If there is no meaningful clinical benefit or if the disease has progressed to a point where treatment is no longer helpful, your doctor may decide to discontinue Ebixa. Do not stop taking the medication without consulting your doctor first.

What Are the Side Effects of Ebixa?

The most common side effects of Ebixa include headache, drowsiness, constipation, elevated liver function tests, dizziness, balance disorders, breathlessness, and high blood pressure. Most side effects are mild to moderate and tend to improve over time.

Like all medicines, Ebixa can cause side effects, although not everybody gets them. The observed side effects are generally mild to moderate in severity. If any side effects become severe or persistent, or if you notice any effects not listed here, please consult your doctor or pharmacist.

If you experience any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed above. Reporting suspected side effects after a medicine has been authorised is important, as it allows continuous monitoring of the medicine’s benefit-risk balance. You can report side effects through your national pharmacovigilance system.

How Should You Store Ebixa?

Store Ebixa at room temperature in its original packaging, out of the reach and sight of children. No special storage conditions are required. Do not use after the expiry date printed on the carton and blister.

Keep this medicine out of the sight and reach of children at all times. Do not use Ebixa after the expiry date which is stated on the carton and blister after “EXP”. The expiry date refers to the last day of that month. No special storage conditions are required for Ebixa tablets.

For the oral solution, once opened, the bottle should be used within 3 months. Check the product leaflet for specific storage instructions for the solution formulation.

Do not throw away medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. These measures will help protect the environment from pharmaceutical contamination.

What Does Ebixa Contain?

The active substance is memantine hydrochloride. Each tablet contains 5 mg, 10 mg, 15 mg, or 20 mg of memantine hydrochloride, corresponding to 4.15 mg, 8.31 mg, 12.46 mg, or 16.62 mg of memantine respectively. The oral solution contains 10 mg/ml memantine hydrochloride.

Active Ingredient

The active substance is memantine hydrochloride. The following table shows the memantine content per tablet strength:

Inactive Ingredients (Excipients)

5 mg, 15 mg, and 20 mg tablets (tablet core): microcrystalline cellulose, croscarmellose sodium, colloidal anhydrous silica, magnesium stearate. Film coating: hypromellose, macrogol 400, titanium dioxide (E 171), and for the 15 mg and 20 mg tablets additionally yellow and red iron oxide (E 172).

10 mg tablets (tablet core): microcrystalline cellulose, colloidal anhydrous silica, talc, magnesium stearate. Film coating: methacrylic acid – ethyl acrylate copolymer (1:1), sodium lauryl sulfate, polysorbate 80, talc, triacetin, and simethicone emulsion.

Tablet Appearance

• 5 mg: White to off-white, oblong, film-coated tablet marked “5” on one side and “MEM” on the other
• 10 mg: Pale yellow to yellow, oval, film-coated tablet with a breakline, marked “1 0” on one side and “M M” on the other. The tablet can be divided into two equal doses.
• 15 mg: Orange to grey-orange, oblong, film-coated tablet marked “15” on one side and “MEM” on the other
• 20 mg: Pale red to grey-red, oblong, film-coated tablet marked “20” on one side and “MEM” on the other

Starter Pack

A starter pack contains 28 tablets in 4 blisters: 7 tablets of 5 mg, 7 tablets of 10 mg, 7 tablets of 15 mg, and 7 tablets of 20 mg. This pack is designed to simplify the dose titration process during the first four weeks of treatment.

How Does Ebixa Work in the Body?

Memantine is a voltage-dependent, moderate-affinity, uncompetitive NMDA receptor antagonist. It blocks pathologically elevated glutamate signalling that damages neurons in Alzheimer’s disease, while allowing normal physiological NMDA receptor activation required for learning and memory.

The brain uses chemical messengers called neurotransmitters to transmit signals between nerve cells. Glutamate is the most abundant excitatory neurotransmitter in the brain and plays a critical role in learning, memory formation, and synaptic plasticity. Under normal conditions, glutamate briefly activates NMDA receptors to transmit information, then is rapidly cleared from the synaptic cleft.

In Alzheimer’s disease, the clearance of glutamate is impaired, leading to chronically elevated levels of this neurotransmitter in the brain. This persistent overstimulation of NMDA receptors – a process called excitotoxicity – causes a constant influx of calcium ions into nerve cells, disrupting normal signal processing and ultimately leading to cell death. This excitotoxic damage compounds the damage caused by amyloid plaques and tau tangles, accelerating cognitive decline.

Memantine addresses this problem by acting as an uncompetitive antagonist at the NMDA receptor. In its resting state, the NMDA receptor channel is blocked by magnesium ions. Under normal physiological conditions, when a nerve impulse arrives, glutamate and co-agonists briefly open the channel, displacing the magnesium block and allowing calcium to enter. Memantine mimics this magnesium block: under conditions of chronic, low-level glutamate overstimulation (the “noise”), memantine sits in the channel and blocks the pathological calcium influx. However, when a genuine, strong nerve signal arrives (the “signal”), the voltage change is sufficient to displace memantine from the channel, allowing normal signal transmission to occur.

This ability to distinguish between pathological noise and genuine signals is what makes memantine therapeutically useful. Unlike more potent NMDA antagonists such as ketamine, which block the receptor more completely and prevent all signalling (including normal learning), memantine selectively reduces the background excitotoxic damage while preserving the meaningful nerve signals needed for cognitive function.

Pharmacokinetic Profile

Memantine is well absorbed after oral administration with an absolute bioavailability of approximately 100%. Peak plasma concentrations are reached within 3–8 hours after dosing. Food does not affect absorption. The drug has a large volume of distribution (approximately 10 L/kg), indicating extensive tissue distribution.

Approximately 45% of memantine is bound to plasma proteins. The drug is partially metabolised in the liver, but not by cytochrome P450 enzymes, which significantly reduces the potential for drug-drug interactions compared to many other centrally acting medications. The primary metabolites have minimal NMDA receptor antagonist activity.

Memantine has a terminal elimination half-life of 60–100 hours, allowing for once-daily dosing. It is primarily excreted unchanged in the urine (approximately 48% as unchanged drug). Renal elimination is partly dependent on urinary pH – alkaline urine can reduce the excretion of memantine, potentially increasing its blood levels. This is why significant dietary changes that affect urinary pH should be reported to your doctor. Steady-state plasma concentrations are achieved within approximately 3 weeks of starting treatment.

Frequently Asked Questions About Ebixa