Drugs address cognitive and behavioral function
No currently available treatments can cure or significantly alter the progression of AD, but two classes of medications are used in an attempt to improve cognitive function. One is cholinesterase inhibitors (ChEIs), which potentiate acetylcholine synaptic transmission. The other is N-methyl-D-aspartate (NMDA) glutamate receptor blockers. Other classes of drugs are sometimes used to treat behavioral symptoms, such as agitation, aggression, mood disorders, and psychosis (eg, delusions, hallucinations).
Cognitive function. Results from studies of pharmacologic management of MCI vary widely, but recent reviews have found no convincing evidence that either ChEIs or NMDA receptor blockers have an effect on progression from MCI to dementia.21,22 Neither class is FDA-approved for treatment of MCI.
In patients with dementia, the effects of ChEIs and NMDA receptor blockers on cognition are statistically significant but modest and often of questionable clinical relevance.23 Nonetheless, among ChEIs, donepezil is approved by the FDA for mild, moderate, and severe dementia, and galantamine and rivastigmine are approved for mild and moderate dementia. There is no evidence that one ChEI is more effective than another,24 and the choice is often guided by cost, adverse effects, and health plan formularies. Memantine, the only FDA-approved NMDA receptor blocker, is approved for moderate to severe dementia and can be used alone or in combination with a ChEI.
If these drugs are used in an attempt to improve cognition in AD, guidelines recommend the following approach for initial therapy: Prescribe a ChEI for the mild stage, a ChEI plus memantine for the moderate stage, and memantine (with or without a ChEI) for the severe stage.25 The recommendations also include monitoring every six months.
There is no consensus about when to discontinue medication. Various published recommendations call for continuing treatment until the patient has “lost all cognitive and functional abilities;”22 until the patient’s MMSE score falls below 10 and there is no indication that the drug is having a “worthwhile effect;”21 or until he or she has reached stage 7 on the Reisberg Functional Assessment Staging scale, indicating nonambulatory status with speech limited to one to five words a day.10
Behavioral function. A variety of drugs are used to treat behavioral symptoms in AD. While not FDA-approved for this use, the most widely prescribed agents are second-generation antipsychotics (aripiprazole, olanzapine, quetiapine, and risperidone). The main effect of these drugs is often nothing more than sedation, and one large multisite clinical trial concluded that the adverse effects offset the benefits for patients with AD.26 Indeed, the FDA has issued an advisory on the use of second-generation antipsychotics in AD patients, stating that they are associated with increased mortality risk.27 The recently updated Beers Criteria strongly recommend avoiding these drugs for treatment of behavioral disturbances in AD unless nonpharmacologic options have failed and the patient is a threat to self or others.28
Because of the black-box warning that antipsychotics increase the risk for death, some clinicians have advocated obtaining informed consent prior to prescribing such medications.29 At the very least, when family or guardians are involved, a conversation about risks versus benefits should take place and be documented in the medical record.
Other drug classes are also sometimes used in an attempt to improve behavioral function, including antiseizure medications (valproic acid, carbamazepine), antidepressants (trazodone and selective serotonin reuptake inhibitors), and anxiolytics (benzodiazepines and buspirone). Other than their sedating effects, there is no strong evidence that these drugs are effective for treating dementia-related behavioral disorders. If used, caution is required due to potential adverse effects.
NONPHARMACOLOGIC MANAGEMENT IS "PROMISING"
A recent systematic review of nonpharmacologic interventions for MCI evaluated exercise, training in compensatory strategies, and engagement in cognitively stimulating activities and found “promising but inconclusive” results. The researchers found that studies show mostly positive effects on cognition but have significant methodologic limitations.30 Importantly, there is no evidence of delayed or reduced conversion to dementia.
For patients who already have mild-to-moderate dementia, cognitive stimulation seems to help in the short term.31 There is also some evidence that exercise and occupational therapy may slow functional decline,32 but the effects are small to modest and their actual clinical significance (eg, the ability to delay institutionalization) is unclear. There is promising but preliminary evidence that cognitive rehabilitation (helping patients devise strategies to complete daily activities) may improve functioning in everyday life.33
While behavioral symptoms are often due to the dementia itself, it is important to identify and treat medical and environmental causes that may be contributing, such as infection, pain, and loud or unsafe environments. As noted before, nonpharmacologic treatments are generally preferred for behavioral problems and should be considered prior to drug therapy. Approaches that identify and modify both the antecedents and consequences of problem behaviors and increase pleasant events have empiric support for the management of behavioral symptoms.34 Interventions including massage therapy, aromatherapy, exercise, and music therapy may also be effective in the short term for agitated behavior.35
Caregivers should be encouraged to receive training in these strategies through organizations such as AA. Caregiver education and support can reduce caregivers’ distress and increase their self-efficacy and coping skills.36
Continue: Is it time for hospice? >>