TREATMENTS FOR ALZHEIMER’S DISEASE
CHOLINESTERASE INHIBITORS
In Alzheimer’s Disease (AD), especially in advanced stages, some neurons in the brain become less excitable. This means they do not send signals efficiently, causing slower communication between neurons.
Cholinesterase inhibitors are medications used to improve this communication. They work by increasing neurotransmission (signal transfer) between nerve cells, which helps reduce some symptoms of Alzheimer’s disease.
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Donepezil (Aricept)
Donepezil is a first-line treatment for AD because it helps improve cognitive function such as memory and thinking.
High-dose donepezil improved cognitive function more effectively than the standard dose.
However, high-dose donepezil increased the risk of heart-related problems. Patients with heart disease should be careful while using donepezil.
Donepezil may temporarily improve cognitive performance in Mild Cognitive Impairment (MCI), but it does not effectively prevent progression to Alzheimer’s disease. Donepezil increased the risk of side effects such as nausea, vomiting, and diarrhea.
Rivastigmine (Exelon)
Rivastigmine is mainly used to treat mild to moderate dementia in Alzheimer’s and Parkinson’s patients.
Recent studies also suggest that rivastigmine may improve gait stability, which can reduce the risk of falls in Parkinson’s patients. It improved cognitive function (memory and thinking), better ability to perform daily activities, and improved overall clinical assessment by doctors.
Galantamine (Razadyne)
Galantamine is a natural alkaloid compound found in plants such as Galanthus nivalis (snowdrop).
Galantamine inhibits the enzyme acetylcholinesterase, which helps increase the level of acetylcholine in the brain. This neurotransmitter is important for memory and learning.
It is used to treat mild to moderate Alzheimer’s disease.
Galantamine use should be carefully monitored because it has potential side effects.
Tacrine (Cognex)
Tacrine was developed to improve cognitive symptoms such as memory and thinking in Alzheimer’s patients.
It improved cognitive performance and small improvements in behavioral symptoms. However, the improvement was modest and did not cure the disease.
Although tacrine showed some benefits, the drug caused significant side effects, especially liver toxicity.
Because of these safety concerns and the development of safer cholinesterase inhibitors drugs, tacrine use gradually declined. Today, it is rarely used in clinical practice.
Combination therapy with memantine and cholinesterase inhibitors may provide short-term cognitive benefits, but more research is needed.
NMDA RECEPTOR ANTAGONISTS IN ALZHEIMER’S DISEASE
NMDA receptors help control calcium (Ca²⁺) entry into neurons. Calcium is essential for learning, memory, synaptic plasticity.
In AD, Aβ disrupts NMDA receptor function. This causes excess calcium influx (calcium dysregulation) and excess calcium damages neurons and contributes to disease progression
Memantine
Memantine is effective for moderate to severe Alzheimer’s disease, improving cognition, behavior, and daily functioning.
It works by blocking excessive NMDA receptor activity, protecting neurons.
Combination therapy with cholinesterase inhibitors may improve cognition, behavior, and daily functioning, although the strength of evidence varies.
Clinical studies suggest that memantine can reduce disease worsening and improve overall symptoms in Alzheimer’s patients.
Side effects
Possible side effects include dizziness and headache (possible). However no increased risk of falls was reported.
Ketamine (Ketalar)
Ketamine is a drug used mainly for anesthesia. It is both water-soluble and fat-soluble, which allows it to act quickly in the body.
Role of Ketamine
- It is metabolized in the liver.
- It can cause bronchodilation, meaning it opens the airways.
- It stimulates the cardiovascular system.
- It produces a unique type of anesthesia called “dissociative anesthesia,” where patients feel detached from their surroundings.
Clinically, ketamine is used during different stages of anesthesia in medical procedures.
Studies showed that ketamine can rapidly reduce symptoms of depression. It has relatively fewer side effects compared with some treatments. It may help treat several neurological disorders including Parkinson’s diseases, multiple sclerosis and stroke.
Recent research suggests that ketamine may protect brain function. It reduces depression associated with AD and improve some symptoms related to neurodegeneration.
However, more research is needed before ketamine can be widely used as a treatment for Alzheimer’s disease.
Dextromethorphan
For many decades, dextromethorphan has been a common ingredient in over-the-counter cough medicines used to relieve dry cough.
Neurodegenerative diseases such as Alzheimer’s disease are associated with chronic inflammation in the brain.
Long-term inflammation in these cells can damage neurons and contribute to neurodegeneration.
Researchers found that reducing this inflammation could slow neuronal loss.
Studies suggest that dextromethorphan may help reduce neuroinflammation because it can inhibit neurotoxicity and significantly protect neurons from damage
ANTIDEPRESSANTS IN ALZHEIMER’S DISEASE
Although antidepressants are mainly used to treat mood disorders like depression, recent studies suggest they may also help manage neuropsychiatric symptoms in Alzheimer’s disease patients, such as depression, agitation and anxiety.
SSRIs as antidepressants
Among antidepressants, Selective Serotonin Reuptake Inhibitors (SSRIs) are often preferred over other antidepressants.
SSRIs work by increasing serotonin activity in the brain (about 90%). Higher serotonin levels help improve mood, emotional stability, and cognitive function.
Research suggests antidepressants may have neuroprotective benefits, such as increasing serotonin levels, cognitive function and long-term memory improvement. It reduce brain inflammation and maintain neurotransmitter balance. These effects may delay the onset of Alzheimer’s disease.
Antidepressants can also improve mood, reduce anxiety, and enhance quality of life in AD patients.
Another class of antidepressants is Serotonin–Norepinephrine Reuptake Inhibitors (SNRIs) such as Duloxetine (Cymbalta), Venlafaxine (Effexor).
Both neurotransmitters are important for mood regulation and relief of depressive symptoms.
ANXIOLYTICS IN ALZHEIMER’S DISEASE
Benzodiazepines
Lorazepam (Ativan) and Alprazolam (Xanax) are benzodiazepines, a group of medications used to treat anxiety, panic disorders, and sleep problems.
These drugs work by acting on GABA-A receptors in the brain, which increase the effect of GABA, a neurotransmitter that calms brain activity.
Benzodiazepines are sometimes prescribed for anxiety or sleep disturbances in AD patients. However, their use in older adults with dementia is controversial and generally discouraged.
Side effects
Benzodiazepines can cause several problems in elderly AD patients, such as increased confusion, slower thinking and mental processing
It also causes sedation or excessive drowsiness and higher risk of falls and injuries.
Because of these risks, doctors usually avoid benzodiazepines in AD patients and prefers alternative treatments.
Buspirone (Buspar)
Buspirone is an anti-anxiety medication that reduces anxiety without the strong sedative effects seen with benzodiazepines.
Research suggests that buspirone may help control anxiety symptoms in people with Alzheimer’s disease.
Unlike benzodiazepines, it is less likely to cause sedation, confusion, or cognitive slowing, which makes it a safer option for elderly patients with dementia.
Studies indicate that buspirone can also help manage behavioral problems in dementia patients, such as agitation, irritability and anxiety-related behavioral disturbances.
Hydroxyzine (Vistaril)
Hydroxyzine is an antihistamine drug that also has sedative (calming and sleep-inducing) effects. It can be used to reduce anxiety in patients with AD.
Studies suggest that hydroxyzine can be as effective as other anti-anxiety drugs such as buspirone and benzodiazepines. It is generally well tolerated by patients.
Side Effects
However, hydroxyzine may cause more sedation than other anxiety medications, including sleepiness and drowsiness
Hydroxyzine blocks acetylcholine activity (anticholinergic effects). Since acetylcholine is already reduced in Alzheimer’s disease, these effects may worsen cognitive decline and increase confusion.
Gabapentin (Neurontin)
Gabapentin is not usually the first medication used to treat anxiety in AD. However, doctors may consider it when other anxiety treatments do not work or are not tolerated.
Gabapentin may help control anxiety in AD by reducing excitatory brain activity and increasing inhibitory signaling, but because evidence is limited, it is usually used only when first-line treatments are ineffective.
MONOCLONAL ANTIBODIES
Aducanumab
Aducanumab is a monoclonal antibody drug developed to treat AD by targeting the underlying pathology rather than just symptoms.
It is help patients with mild cognitive impairment due to Alzheimer’s disease or early-stage Alzheimer’s dementia.
Aducanumab specifically binds to β-amyloid (Aβ) proteins. By binding to these forms, it helps clear amyloid plaques from the brain.
Aducanumab is able to remove amyloid plaques, not on clear proof that it improves memory or slows cognitive decline.
Its approval is controversial because clear evidence that it improves cognitive function is still lacking, and further studies are underway to confirm its effectiveness.
Lecanemab
Lecanemab is used to treat early-stage Alzheimer’s disease. It works by targeting amyloid-beta (Aβ) proteins that accumulate in the brain.
Lecanemab reduced amyloid plaque levels in the brain and slowed cognitive decline compared with placebo.
Side effects
Treatment may carry significant risks, such as brain swelling or bleeding (commonly referred to as ARIA in clinical discussions).
The medication may have very high treatment costs, raising concerns about accessibility and healthcare burden.
Donanemab
Donanemab is works by targeting and removing amyloid-β (Aβ) plaques from the brain.
This indicates donanemab significantly slowed clinical progression of Alzheimer’s disease in these patients.
Side effects
Many patients developed Amyloid‑Related Imaging Abnormalities (ARIA), which includes brain swelling or microbleeds. It occurred in 26–30% of participants in trials. Because of this, the overall clinical benefit and safety balance is still being evaluated.
Studies suggest that both Donanemab and Lecanemab work better in early stages of Alzheimer’s disease.
Patients with lower amyloid levels at the start of treatment showed greater benefits, while those with advanced disease had less improvement.
Non-pharmacological management strategies
Cognitive stimulation therapy (CST)
It includes structured mental activities and discussions, such as:
Reminiscence therapy (talking about past experiences)
Reality orientation (helping patients stay aware of time, place, and person)
Cognitive stimulation is non-drug therapy that can be as effective as cholinesterase inhibitors in slowing cognitive decline, especially in mild-to-moderate dementia.
Cognitive stimulation therapy aims to maintain and improve thinking abilities, slow down disease progression. This therapy support memory and reasoning , social interaction , independence (daily activities), self-esteem, emotional stability, and quality of life (for both patients and caregivers)
Reality Orientation Therapy (ROT)
It is a non-drug intervention used for people with memory loss (amnesia), confusion and difficulty understanding time, place, and surroundings. These problems are very common in Alzheimer’s patients.
The main aim of ROT is to reconnect patients with reality by repeatedly reminding them about who they are (personal history), where they are (environment) and what time/date it is. This is done using multisensory cues (visual, verbal, environmental reminders).
ROT is not a replacement for medication but works alongside it. For example, when ROT combined with Acetylcholinesterase inhibitors, patients showed better cognitive improvement as compared to medication alone.
ROT helps AD patients by reducing confusion and improving awareness of their surroundings, especially when combined with medication. It is a structured, supportive approach that enhances cognitive outcomes over time.
Music therapy
It is a non-drug treatment that uses music to reduce stress and emotional distress, improve mood and behavior and help patients cope with psychological symptoms. It can also distract patients from confusion and improve overall well-being.
Music can trigger MEAMs (music-evoked autobiographical memories). These are personal memories from the past often very vivid and emotional and sometimes recalled even when general memory is impaired.
Music activates areas like the anterior hippocampus which links emotion and memory recall.
Limitation: Music therapy benefits may last only up to ~3 months.
Physical exercise
Many studies (both RCTs and non-RCTs) show that physical exercise can improve cognitive function (memory, thinking), help with daily activities, reduce neuropsychiatric symptoms (e.g., anxiety, agitation), and enhance overall physical health and mobility
When compared to drugs like Cholinesterase inhibitors, exercise may be more effective in some aspects and patients are more likely to stick with (better adherence) exercise programs than long-term medication use.
Occupational therapy (OT)
Occupational therapy focuses on helping patients maintain independence in daily life.
It also teaches caregivers practical strategies to handle cognitive decline. The main benefits of OT id to improves patients’ ability to perform daily activities, stay engaged in meaningful tasks, and cope with memory and thinking problems
In OT patients are guided to identify personally meaningful activities, simplify tasks for better participation and reduce distractions and stress in their environment.
These therapies show positive effects, especially in engagement and quality of life. However, more research is still needed to fully confirm their long-term effectiveness.
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