Dementia Medication Overview

Can Dementia Be Treated with Medication?

Most diseases that cause dementia are progressive, which means that persons with the disease get worse over time. Unfortunately, no curative treatment for dementia is currently available. Some medications, however, can temporarily improve symptoms and functioning and may slow the progression of the basic disease process. Efforts to find effective drug therapy for dementia have frustrated scientists.

Can Dementia Be Treated with Medication?

Many drugs used for dementia are limited by side effects, short duration of action, and the need for frequent monitoring of blood levels or other laboratory values to prevent toxicity. Many assessment tools have been used to measure the effectiveness of dementia drugs, but effectiveness remains difficult to evaluate. Additionally, an enormous amount of dementia-related treatment information from a wide variety of sources is directed to consumers, including information on medications, herbal products, diet, exercise, and nutrition. The vast amount of material and its sometimes-questionable reliability make it difficult to distinguish fact from rumor. Despite these difficulties, researchers continue to search for drugs with improved effectiveness and better tolerability.

Medical treatment is directed toward treating dementia, improving coexisting behavioral changes (for example, psychosis, anxiety, depression), and evaluating the benefit of other therapeutic interventions.

Acetylcholinesterase inhibitors

Acetylcholinesterase (AChE) inhibitors like tacrine (Cognex), donepezil (Aricept), galantamine/ galanthamine (Reminyl), and rivastigmine (Exelon) are approved by the United States Food and Drug Administration (FDA) for treatment of Alzheimer disease. They may be useful for other similar diseases causing dementia (for example, Parkinson disease). Unfortunately, improvement is neither dramatic nor permanent.

• How AChE inhibitors work: AChE inhibitors delay the breakdown of acetylcholine, a brain chemical needed for nerve cells to communicate. They may be useful for mild-to-moderate Alzheimer disease. Once AChE inhibitors are started, they should be continued indefinitely. Stopping the medication may cause an abrupt, and possibly severe, cognitive and behavioral decline that may not be resolved by restarting the AChE inhibitor. The cause for this potentially catastrophic decline with the discontinuation of the AChE inhibitors is not known.
• Who should not use these medications: People with the following conditions should not use AChE inhibitors:
  • Allergy to AChE inhibitors
  • Liver disease (avoid tacrine
    • Use: AChE inhibitors come in tablets or capsules. The daily dose depends on the particular drug prescribed.
    • Drug or food interactions: Certain drugs like cimetidine (Tagamet), ketoconazole (Nizoral), ritonavir (Norvir), paroxetine (Paxil), and erythromycin (E-Mycin) may increase AChE inhibitor toxicity. Certain drugs known as anticholinergics (antihistamines, bladder-control drugs) may decrease AChE inhibitors’ effectiveness. Other AChE inhibitors (often used during surgery) may increase effects.
    • Side effects: AChE inhibitors may cause nausea, vomiting, diarrhea, muscle cramps, headaches, dizziness, fainting, appetite loss, and skin reddening. These effects can be lessened if the drugs are started at low doses then slowly increased until the desired maintenance dose is reached. Tacrine has a higher incidence of nausea, vomiting, and diarrhea, and persons taking tacrine must have their blood drawn on a regular basis to monitor for liver toxicity. Donepezil can cause abnormal dreams. Patients with heart rhythm disturbances (donepezil) or history of seizures (galantamine/galanthamine) are advised to use AChE inhibitors with caution.

Drugs within the class known as N-methyl-D-aspartate (NMDA) blockers include memantine (Namenda), which has been approved by the FDA for the treatment of moderate-to-severe Alzheimer disease. After NMDA blockers are started, a notable improvement in basic activities of daily living (for example, eating, grooming, dressing) is noted. This drug can be used in combination with existing AChE inhibitors. Although observed effects will be modest, these improvements significantly aid caregivers, such as nursing home personnel or family members, in their interactions with these patients.

• How NMDA blockers work: NMDA blockers guard against overexcitement of NMDA receptors by the brain chemical glutamate. Overexcitement of NMDA receptors by abnormally high brain levels of glutamate is thought to be responsible for decreased nerve cell function and, eventually, nerve cell death. NMDA blockers may also be helpful in other neurodegenerative conditions, such as Huntington disease, AIDS-related dementia, and vascular dementia.
• Who should not use these medications: People with allergy to NMDA blockers should not take them.
• Use: Tablets may be swallowed with or without food.
• Drug or food interactions: Drugs that alter urine acidity, like sodium bicarbonate or acetazolamide (Diamox), may cause memantine to accumulate in the body.
• Side effects: Common adverse effects include dizziness, headache, and constipation.

• Amyloid deposit inhibitors: Clioquinoline, an antibiotic, may help reduce amyloid deposits in the brains of persons with Alzheimer disease.

• Antipsychotic drugs: Haloperidol (Haldol), risperidone (Risperdal), olanzapine (Zyprexa), and quetiapine (Seroquel) are frequently prescribed to help manage psychosis and agitation. Treatment of dementia-associated psychosis or agitation is intended to decrease psychotic symptoms (for example, paranoia, delusions, hallucinations), screaming, combativeness, and/or violence. The therapeutic goal is increased comfort and safety of patients, families, and caregivers.
• Antidepressant drugs: Depression is frequently associated with dementia and generally worsens the degree of cognitive and behavioral impairment.
• Antianxiety drugs: Many patients with dementia experience anxiety symptoms. Although benzodiazepines like diazepam (Valium) have been used for treating anxiety in other situations, they are often avoided because they may increase agitation in persons with dementia or are too sedating. Buspirone (Buspar) is often initially tried for mild-to-moderate anxiety.

Data continue to emerge regarding other potential interventions that may treat dementia or decrease the risk of developing it. Observations of the following interventions are preliminary and are considered uncertain regarding their benefit in preventing or delaying disease progression.

• Selegiline (Eldepryl): Some studies have reported that selegiline, a drug used in the treatment of Parkinson disease, may improve behavior, functional performance, and cognitive function. Mood enhancement may play a role in the apparent improvement in cognition.
• Estrogens: In women, estrogens may enhance nerve cell function after menopause.
• Antioxidants: High doses of vitamin E (1000 units twice daily) may be beneficial in delaying functional deterioration in vascular dementia. Such high doses of vitamin E can cause bleeding problems in some people. The addition of vitamin C may enhance the beneficial effects.
• Anti-inflammatory agents: Nonsteroidal anti-inflammatory drugs (NSAIDs) include agents like ibuprofen (Motrin, Advil) and naproxen (Aleve). NSAIDs may decrease inflammatory changes that are common in Alzheimer disease, or they may inhibit platelets, thereby protecting blood flow in the brain.
• Statins: The Canadian Study of Health and Aging noticed that people using statins (for example, atorvastatin [Lipitor], pravastatin [Pravachol], or simvastatin [Zocor]) to lower cholesterol showed lower odds of developing Alzheimer disease.