Review Article |
Corresponding author: Hany Akeel Al_hussaniy ( hany_akeel2000@yahoo.com ) Academic editor: Plamen Peikov
© 2023 Hany Akeel Al_hussaniy, Zahraa Alkhafaje, Zahraa S. Altamimi, Amjad I. Oraibi, Aboalhassan Hayder Abdalhassan, Hayder M. Abdulhamza, Mohammed J AL-Zobaidy.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Al_hussaniy HA, Alkhafaje Z, Altamimi ZS, Oraibi AI, Abdalhassan AH, Abdulhamza HM, AL-Zobaidy MJ (2023) Memantine and its role in parkinsonism, seizure, depression, migraine headache, and Alzheimer’s disease. Pharmacia 70(2): 291-297. https://doi.org/10.3897/pharmacia.70.e99311
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Alzheimer’s disease (AD) is a neurological disorder characterized by mental and behavioral changes that develop progressively with a decline in brain function. Dysfunctions in glutamatergic and cholinergic pathways, along with an increased concentration of beta-amyloid protein (Aβ), lead to synapses that are full of phosphorylated protein. These changes result in several pathological, biochemical, cellular, and molecular alterations that increase neural excitation directly or indirectly at the neural level, affecting the synapse, axons, signal transmission, and all parts of neurons. All these alterations, with continuous excitatory effects, eventually lead to neural loss and degradation due to stimulation of the immune response.
However, memantine is a non-competitive antagonist of N-methyl-D-aspartic acid (NMDA) glutamatergic receptors of moderate affinity and voltage-dependent that blocks the effects of pathologically elevated glutamate tonic levels, which can lead to neuronal dysfunction. Memantine has shown improvement in cognition, global clinical status, activities of daily living, and behavioral disturbances in moderate and severe AD.
In this review, we will discuss the effects of memantine use and side effects, as well as its application in treating other diseases or pathological conditions with the prospective use of memantine or an alternative. Memantine is generally well-tolerated, and the most common adverse reactions are vertigo, headache, and hallucinations, which are usually mild.
N-Methyl aspartate, Alzheimer Disease, Cholinergic Agents, Glutamates, Memantine
Worldwide, Alzheimer’s disease is a significant health concern that is associated with symptoms and diseases of aging (
The increase in the prevalence of Alzheimer’s disease is also associated with a rise in high socio-health costs at the national level, which is expected to become even more significant in the future (
However, early diagnosis and treatment of Alzheimer’s disease could reduce the socioeconomic cost of the disease. The goal of treatment is to delay the appearance of disease symptoms, reduce functional deterioration, improve patients’ quality of life, and relieve the burden on family members and caregivers (Sonkusare 2005).
The impact of antidementia drugs, such as memantine, on cost-effectiveness can be measured through various parameters, including economic factors such as hospital admissions, delay in institutionalization, emergency care costs, need for more continuous care, and use of psychotropic drugs. Other factors are more related to the quality of life of the patient and caregiver (
This review highlights the role of memantine in Alzheimer’s disease, ranging from its indications and contraindications to its ability to improve cognitive, behavioral, and functional symptoms, as well as the quality of life of patients.
In 1966, memantine was discovered as a drug for treating hyperglycemia to treat high blood glucose. It has been shown not to have a significant effect on decreasing blood glucose. However, after this drug was developed in the enter clinical phases due to the prospect of an effect on the treatment of parkinsonism, seizure, depression, margin headache, and finally, Alzheimer’s disease (
As the only non-competitive NMDA receptor antagonist currently in clinical practice, memantine can inhibit the excessive activation of NMDA receptors to reduce excitotoxicity and protect neurons without affecting the physiological activation of NMDA receptors required for cognition (
Many countries and institutions have decided to use memantine to treat Alzheimer’s and reduce its symptoms. According to studies, some preferred memantine anti-acetylcholine esterase drugs, while others decided to leave it alone to treat Alzheimer’s and reduce symptoms. For example, not loss, both the Behavioral Neurology and Dementia Study Group and the Neuropharmacology Group recommend memantine treatment in patients with probable or possible moderate or severe AD according to the NINCDS-ADRA criteria (National Institute of Neurologic, Communicative Disorders and Stroke-Alzheimer’s Disease and Related Disorders Association) (level of evidence I, grade of recommendation A). It is also commented that combined use with a cholinesterase inhibitor (ACEI) in these phases is more beneficial than monotherapy with acetylcholine esterase inhibitors (level of evidence II, grade of recommendation B) (
The National Institute of Health and Care Excellence (NICE) guidelines in the United Kingdom recommend memantine monotherapy in patients with moderate AD who are intolerant or have a contraindication to using acetylcholine inhibitors in patients with AD in the severe phase of the disease (
For patients with an established diagnosis of AD who are taking acetylcholine inhibitors, the following is included:
Its prescription must be made under the following conditions: a) prescriptions made by specialists such as neurologists, geriatricians, and psychiatrists; b) other health professionals, such as primary care physicians, if they have an expert degree in the diagnosis and treatment of AD; and c) do not suspend treatment with acetylcholine inhibitors in people with AD solely based on advanced disease.
Memantine benefits patients with moderate to severe AD, and this benefit affects cognition, functionality, and psychological and behavioral symptoms. The association of memantine and acetylcholine inhibitors produces less deterioration than a placebo. However, memantine is probably not better in patients with mild AD than in a placebo.
Overall, the evidence for memantine for AD is of high quality, coming from many trials in thousands of patients. We can be confident in the AD results, but this is not the case in patients with other types of dementia (
Memantine is a non-competitive antagonist of NMDA (N-methyl-D-aspartate acid) glutamatergic receptors. These receptors are calcium channels, and through their action, high levels of glutamate are regulated, ultimately responsible for neuronal dysfunction and death (
Several studies are trying to understand the mechanism of action of memantine and its neuroprotective effects that decrease the level of excitatory neurotransmitters. So the use of memantine is not limited to Alzheimer’s only. In the Straathof et al. study, memantine could help treat obsessive-convulsive disorder (OCD) and reduce abnormalities in dopaminergic neurons (
Physiologically, memantine and magnesium occupy the same NMDA receptor and are mutually exclusive as long as the channel is not blocked in the presence of both compounds (
Illustrates the mechanism of action of memantine and the against an antagonist of NMDA receptors. (A) Show the site of binding of the agonist and co-agonist to the receptor site, which results in an increase in intracellular Ca and a neuroexcitatory, (B) Show the NMDA receptor antagonist or block the entry of Ca, which results in neuroprotection.
Memantine has been shown to improve cognition, global clinical status, activities of daily living, and behavioral changes in moderate and severe AD. Like acetylcholine inhibitors, although the overall benefit is modest, the interindividual response to memantine is variable (level of evidence I, grade of recommendation A) (
The dose of memantine is well tolerated, reaching a maximum dose of about 28 mg daily. However, the dose can gradually increase every week to reach the maintenance dose to produce a better-tolerated effect with minimal side effects, and this can be achieved by gradually increasing the dose to 5 mg each week for the first three weeks as follows: memantine 5 mg at breakfast in the first week followed by 10 mg in the second, 15 mg for the third week, then the maintenance dose can be achieved in week four. The recommended maintenance dose is 20 mg per day. An equivalent liquid formulation can be adjusted easily and is suitable for patients that cannot tolerate tablet formulation (
The memantine tablet can be administered with or without food. However, the dose of memantine must be adjusted in patients with renal impermeant, especially when creatinine clearance reaches approximately (50 ml/minute / 1.73 m2) in this case, the daily dose of memantine is approximately 10 mg per day (Table
Presentations | Posology |
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– Tablets 10 and 20 mg – Tablets 5, 10, 15, and 20 mg (initiator pack) – Or dispersible tablets 10 and 20 mg – Oral solution 5 mg/actuation | 5 mg/day in the first week, increasing by 5 mg every week, up to 20 mg/day in 1 or 2 doses (10 mg in renal failure) |
There are no evidence-based guidelines on when to withdraw this drug. It is recommended to evaluate its effect after six months of treatment. It is recommended to stop treatment if agitation, akathisia, or other neuropsychiatric symptoms appear and if the patient worsens globally faster than without treatment (Reeve et al. 2021).
It is generally a well-tolerated drug, with adverse effects similar to placebo in some studies. The most frequent adverse effects are dizziness, constipation, drowsiness, headache, hypertension, and agitation. In patients with severe renal insufficiency, the dose should be reduced. It has no absolute contraindications, but caution must be exercised in epilepsy, renal failure, or urinary retention (Table
Elevated liver function | Vertigo, balance, and epilepsy |
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Fungal infections | Heart failure |
Drug hypersensitivity | Hypertension Venous thrombosis/thromboembolism |
Drowsiness, confusion, hallucinations* psychotic reactions† | Dyspnea |
Headache fatigue | Constipation vomiting pancreatitis |
Psychological and behavioral symptoms associated with dementia are very common throughout the disease, appearing in up to 80% of patients during its evolution. A meta-analysis showed a significant improvement in agitation, illusions, disinhibition, and sleep-wake rhythm disorders compared to controls, slightly superior in managing hallucinations and irritability. In contrast, it presents similar results to controls in managing negative symptoms (dysphoria, anxiety/phobia, apathy, aberrant motor behavior, and eating behavior disorders) (
Regarding cognitive symptoms, a recent study revealed that the best drug to combat cognitive deterioration was memantine, followed by galantamine.
The main objective of patients with dementia is to maintain functional autonomy. Evidence-based medicine recommends memantine, ACE inhibitors, physical exercise, and dyadic intervention to prolong functional autonomy and delay institutionalization. In patients treated with memantine monotherapy or biotherapy, post hoc analysis shows maintenance of daily activities compared to placebo, with consequent delay in institutionalization (
On the other hand, memantine treatment has been shown to reduce caregiver stress and caregiver care time. In the few studies in this regard, combined therapy further enhances the concept of quality of life. The appropriate choice of treatment and therapeutic expectations is crucial, with real goals for the patient and the caregiver.
In the multicenter DOMINO-AD study (“Donepezil and Memantine in Moderate to Severe Alzheimer’s Disease study”), variables related to the interruption of donepezil treatment or the start of memantine treatment were collected. Both patients who continued taking donepezil and those who started memantine showed less deterioration on the standardized Mini-Mental Test (SMMSE; p < 0.001) and on the Bristol Activities of Daily Living Scale (BADLS; p < 0.001) than those who discontinued donepezil or did not take memantine. Combination therapy (donepezil and memantine) was not significantly superior to donepezil monotherapy for primary or secondary endpoints. The post-analysis of the study data showed that abrupt discontinuation of donepezil increased the risk of worsening the condition within a few weeks of discontinuation and increased hospital admissions during the research period. Taken together, this is the most stressful moment associated with the poor quality of life that their caregivers envision. It is the most conflictive moment related to a worse quality of life perceived by their caregivers (
Talking about dementia in economic terms is always undesirable. However, the reality is that it is one of the clinical entities that cause the most direct and indirect spending at the socio-health level. Combined therapy (ACEI and memantine) continues to be the most cost-effective approach from a health and social perspective, superior to treatment in monotherapy with ACE inhibitors. Studies show the real economic benefits of anti-AD therapies, both in favor of changing ACE inhibitors for memantine and continuing with ACE inhibitors (donepezil) (
There are few studies concerning drug prescription in patients admitted to nursing homes. In indirect analyzes of health costs focused on drugs, it has been observed that the combination of therapies (ACE inhibitors and memantine) is the most cost-effective in reducing the costs derived from institutionalization in a residential center; therefore, its impact is not only economic but also in terms of health standards (
Reviewing publications on the possibility of implementing symptomatic treatment in frontotemporal dementia (FTD) with memantine, a study published in 2018 brings together the results of clinical trials and case studies. The first, published in 2008, includes a family case of FTD, a behavioral variant, treated with memantine 10 mg twice daily. In this case, with a pathogenic mutation (R406W) in the MAPT gene (microtubule-associated protein tau), the author suggests that memantine could stabilize the progression of the symptoms of the disease.
However, the multicenter, randomized, double-blind, placebo-controlled clinical trial NCT00545974 evaluated the efficacy of memantine in mild to moderate FTD. It was concluded that memantine did not reduce symptoms in this type of dementia (
The latest Cochrane publication on the role of memantine in dementias addresses its potential use in FTD. It concludes that there is significantly little certainty in the evidence of its beneficial clinical effect on the GCR (global clinical rating) and behavioral symptoms compared to placebo. Similarly, there are no differences in cognitive function. However, for all results in efficacy, there is uncertainty, and the confidence interval is consistent with more than one conclusion. On the other hand, they consider a great deal of discontinuity in the memantine group regarding therapeutic compliance (compared to placebo), which may be a source of confusion (
Although memantine has been a consolidated drug in the symptomatic treatment of dementia for decades, basic research, essential in translational science, continues to focus on this molecule, revealing promising and interesting results in animal models and opening the possibility of a different clinical approval from the current one (
In a very recent article from 2021, this ability to impact the biological bases of AD is revealed, which, until now, is an enigma. In this work, a benefit is evidenced in the preclinical transgenic mouse model (homozygous Tg4–42) subjected to chronic treatment for four months with memantine at the level of cognitive performance (learning and memory tasks), behavioral symptomatology and pathological correlate, observing a reduction in loss of neurons in CA1 of the hippocampus, as well as decreasing neurogenesis impairment in the dentate gyrus. This effect, key in the mechanisms of neurodegeneration, reopens the debate on the potential usefulness of memantine in earlier phases of Alzheimer’s disease, not only because of the clinical benefit described but also because of its action on the biology of the disease itself, making it a more than symptomatic treatment (
In the past, memantine was suggested to treat migraine headaches; However, the researchers show that some migraine sufferers have benefited from using memantine to treat migraine headaches (
Memantine has also been found useful in treating depression; however, there are debates regarding its effectiveness for this purpose. Major depressive illness, bipolar disorder, postpartum depression, and seasonal affective disorder are just a few examples of the various forms of depression (
The indications for the use of memantine have been reviewed according to different clinical guidelines. The positive impact of the prescription of this drug in monotherapy and dual therapy in patients with Alzheimer’s disease, according to the classic parameters of behavioral neurology, is highlighted. Possible indications in other entities, such as frontal lobe type dementia (DFT), have been discussed. It ends by opening the debate on its potential beneficial effect in earlier phases, both clinically and biologically, thanks to current basic science.