Alzheimer's Disease Medications

• Alzheimer's disease (AD) is the most common cause of dementia in industrialized nations.
• Dementia is a brain disorder that interferes with a person's ability to carryout everyday activities.
• Alzheimer's disease usually affects the parts of the brain that control cognitive (intellectual) functions such as thought, memory, and language.

• Aging is a risk factor for developing Alzheimer's disease (AD), but most experts believe that Alzheimer's disease is not a normal part of aging.
• Family history or genetics may be linked to the cause of Alzheimer's disease, but much research is currently in progress to better understand the cause.
• This research will also assist us in knowing more about how to best prevent and treat Alzheimer's disease.

• Alzheimer's disease begins with subtle symptoms, but gradually becomes worse. Over time, the ability to think and reason clearly, judge situations, solve problems, concentrate, and remember useful information is lost.
• Eventually, people with Alzheimer's disease are unable to take care of their basic needs, or they loose mobility or the ability to speak. Behavior and personality changes are common.
• As Alzheimer's disease progresses, constant supervision becomes essential.

Individuals with Alzheimer's disease should remain physically, mentally, and socially active as long as they are able. It is believed that mental activity can slow the progression of the disease. Puzzles, games, reading, and safe hobbies and crafts are good choices. These activities should ideally be interactive. They should be of an appropriate level of difficulty so that the person does not become overly frustrated.

Behavior disorders such as agitation and aggression may improve with various interventions. Some interventions focus on helping the individual adjust or control his or her behavior. Others focus on helping caregivers and other family members change the person's behavior. These approaches sometimes work better when combined with drug treatment for depression, mood stabilization, or psychosis.

Alzheimer's disease symptoms can sometimes be relieved, at least temporarily, by medication. Many different types of medications have been or are being studied in the treatment of dementia. Currently, the drugs used for Alzheimer's disease are not a cure, but they help slow down the rate of decline in some people. In many people, the effect is modest, and in others, the effect is not noticeable.

Certain drugs, such as anti-inflammatory drugs (ibuprofen), vitamin E, and hormone therapy (estrogen) have been used on a trial basis in people with Alzheimer's disease. Experts think these drugs might help based on what we know from research about Alzheimer's disease. None of these drugs have yet achieved widespread acceptance as treatment for the disease.

The following sections discuss cholinesterase inhibitors and NMDA inhibitors, which have been approved by the US Food and Drug Administration (FDA) for the treatment of moderate to severe Alzheimer's disease.

There is no cure for Alzheimer's, but number of different drugs are in use to treat the disease's symptoms. They target a couple different mechanisms in the brain and nervous system that lead to Alzheimer's-related dementia. Some drugs reduce the amount of enzyme that breaks down a crucial neurotransmitter chemical, while other drugs target the nerve cell receptors themselves.

A number of existing medications and supplements are also under study. Scientists hope these substances can someday prove useful in combating Alzheimers.

Cholinesterase inhibitors include donepezil (Aricept), galantamine (Reminyl), rivastigmine (Exelon), and tacrine (Cognex).

• How cholinesterase inhibitors work: Cholinesterase is an enzyme that breaks down a chemical in the brain called acetylcholine. Acetylcholine acts as an important messaging system in the brain. Brain acetylcholine levels are low in most people with Alzheimer's disease. Cholinesterase inhibitors improve acetylcholine levels by inhibiting the enzyme that breaks down acetylcholine. The first cholinesterase inhibitor, tacrine, has largely been replaced by newer drugs with low risk of liver toxicity.
• Who should not use these medications: Individuals with the following conditions should not take cholinesterase inhibitors.
  • Allergy to cholinesterase inhibitors
  • Allergy to carbamates (rivastigmine)
  • Liver impairment (should not use tacrine or galantamine)
  • Severe kidney impairment (galantamine)
• Use: Administered orally (by mouth)
  • Donepezil may be taken with or without food.
  • Galantamine and rivastigmine should be taken with food or milk.
  • Tacrine should be taken on an empty stomach at least 1 hour before meals (if stomach upset occurs it may be taken with food, although with food in the stomach, less of the drug may be absorbed).
• Drug or food interactions: Additive effects may occur when administered with succinyl choline, other cholinesterase inhibitors, or cholinergic blockers. Quinidine or ketoconazole increase cholinesterase accumulation in the body and cause toxicity. When taken with aspirin, ibuprofen, or arthritis medicine, it may increase the risk of stomach ulcers. Avoid drugs that counteract acetylcholine's effects, such as scopolamine (Transderm-Scop), tolterodine (Detrol), oxybutynin (Ditropan), or benztropine (Cogentin). If taking tacrine, avoid other drugs or herbal products that may increase liver toxicity, such as atorvastatin, estrogen, or acetaminophen.
• Side effects:
  • Common side effects include the following:
    • Dizziness
    • Nausea
    • Vomiting
    • Diarrhea
    • Loss of appetite
    • Abdominal pain
    • Salivation
  • Contact the doctor immediately if the following occur:
    • Fainting
    • Abnormal heart rate
    • Bloody or black, tarry stools
    • Vomiting blood or substance that looks like coffee grounds
    • Seizures
    • Severe stomach pain
  • Use caution if experiencing any of the following:
    • History of seizures
    • Asthma or chronic obstructive pulmonary disease (COPD)
    • Abnormal heart rhythm
    • Active peptic ulcer disease
    • Anesthesia for surgery
    • Liver disease (tacrine)
    • Parkinson's disease
    • High or low blood pressure

NMDA inhibitors include memantine (Namenda).

• How NMDA inhibitors work: Inhibits N-methyl-D-aspartate (NMDA) receptors in the brain. NMDA receptor action is theorized to contribute to Alzheimer's symptoms.
• Who should not use these medications: Individuals with an allergy to NMDA inhibitors, such as memantine or amantadine, should not take them.
• Use: Administered orally (by mouth) with or without food.
• Drug or food interactions:
  • Drugs that increase urine pH (make the urine more alkaline), such as sodium bicarbonate or acetazolamide (Diamox) may increase accumulation of memantine in the body and cause toxicity.
  • Other NMDA inhibitors may increase toxicity, such as amantadine (Symmetrel) or dextromethorphan (Robitussin).
  • Hydrochlorothiazide (HydroDiuril), triamterene (Dyrenium, Maxzide), cimetidine (Tagamet), ranitidine (Zantac), quinidine (Quinaglute), or nicotine may alter the levels of memantine in the body.
• Side effects:
  • Common adverse effects include the following:
    • Dizziness
    • Headache
    • Constipation
    • Increased blood pressure
  • Contact a doctor immediately if the following occur:
    • Increased heart rate
    • Fainting
    • Allergic reaction (itching, hives, swelling of face, hands, tongue, or throat)
  • Use caution with kidney impairment

Various trials are in progress to find other treatments for Alzheimer's disease. The following list includes some drugs that have been studied or are currently being studied. Some of these drugs are already on the market and used for other diseases or indications, while others are investigational drugs not yet available.

• Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs, such as naproxen (Aleve), have been studied to determine if their anti-inflammatory action slows the brain damage caused by Alzheimer's disease.
• Nutritional and herbal drugs: Vitamin E is being studied to see if it decreases brain damage and ginkgo biloba is being studied to see if it helps decrease symptoms.
• Estrogen: Formal trials have been disappointing; one study showed no effect on Alzheimer's disease progression, another showed women older than 65 years taking estrogen and progesterone had twice the rate of dementia, including Alzheimer's disease.
• Drugs used to decrease heart disease risk: Statin drugs, folic acid, and vitamins B-6 and B-12 are also being studied to see if Alzheimer's disease is decreased when taking these for prevention of heart disease.
• Acetylcholinesterase inhibitors: Ganstigmine (CHF2819), phenserine, zanapezil (TAK-147) are newer cholinesterase inhibitors that have additional protective actions in Alzheimer's disease.
• A-beta production inhibitors: Gamma-secretase inhibitor
• ATP production stimulator: Nicotinamide adenine dinucleotide (NADH, Memex) in theory helps regain normal cellular energy production in Alzheimer's disease to slow progression and alleviate symptoms.