What medication is recommended for an elderly patient experiencing short-term memory loss, possibly due to age-related cognitive decline, trauma, or substance abuse?

Medication for Short-Term Memory Loss in Elderly Patients

For elderly patients with short-term memory loss, initiate donepezil 5 mg once daily as first-line pharmacologic treatment if the cognitive impairment is due to Alzheimer's disease or mild cognitive impairment (MCI) due to AD, but first rule out reversible causes including trauma, substance abuse, metabolic disturbances, and delirium. 1, 2

Critical First Step: Establish the Underlying Cause

Before prescribing any medication for memory loss, you must differentiate between reversible and irreversible causes:

• Rule out delirium and acute confusional states, which are highly prevalent in elderly patients and may be caused by physical illness, drug intoxication, or psychosocial stress—these require prompt medical attention and are potentially reversible 3
• Evaluate for trauma-related memory impairment: If the patient has head trauma with short-term memory deficits (persistent anterograde amnesia), this is a predictor of intracranial injury requiring neuroimaging, not cholinesterase inhibitors 1
• Screen for substance abuse and metabolic disturbances, as these represent causes of cognitive impairment that are not dementia (CIND) and require different management than AD 1
• Obtain comprehensive metabolic panel, complete blood count, thyroid function tests, vitamin B12, and folate levels to identify toxic-metabolic causes or medication effects 4

When Alzheimer's Disease or MCI Due to AD is Confirmed

First-Line Treatment: Donepezil

Start donepezil 5 mg once daily, taken with food to minimize gastrointestinal side effects, and continue for at least 4-6 weeks before considering dose escalation. 2

• Donepezil is the optimal first-line agent due to once-daily dosing, no hepatotoxicity, straightforward titration, milder adverse effects, and lower discontinuation rates compared to other cholinesterase inhibitors 2
• After 4-6 weeks, increase to 10 mg daily if the 5 mg dose is well-tolerated 2, 5
• Cholinesterase inhibitors produce approximately 1-3 point improvements on cognitive scales, equivalent to delaying decline by roughly one year 2

Monitoring and Response Assessment

• Evaluate response over 6-12 months using physician's global assessment, caregiver reports, mental status questionnaires, and functional observations 2
• Beneficial response is defined as stabilization or delayed deterioration, not necessarily improvement 2
• Discontinue donepezil if side effects develop, poor adherence persists, or deterioration continues at the pretreatment rate after 6-12 months 2

Special Considerations for Lower Weight Patients

• Patients weighing less than 55 kg experience more nausea, vomiting, decreased weight, and higher withdrawal rates on donepezil, likely due to higher plasma exposure 5

Alternative and Adjunctive Medications

For Moderate to Severe Dementia

Consider memantine for moderate to severe dementia, which can be used in combination with cholinesterase inhibitors. 2, 6

• Memantine is an NMDA receptor antagonist that works through a different mechanism than cholinesterase inhibitors 6
• Avoid tacrine due to hepatotoxicity risk and complex dosing 2

For Rapid Cognitive Decline

If the patient demonstrates rapid cognitive decline (loss of ≥3 points on MMSE per year), rivastigmine may offer particular benefit, especially in patients with vascular risk factors. 1, 4

• Patients with rapid decline achieve greater benefits from rivastigmine and galantamine compared to other cholinesterase inhibitors 1
• Vascular risk factors should be systematically controlled in these patients 4

For Suspected Dementia with Lewy Bodies

If the patient presents with hallucinations, profound anxiety, psychosis, or personality changes alongside memory loss, suspect dementia with Lewy bodies and refer urgently to a specialist before initiating treatment. 4

• Rivastigmine may offer particular benefit in dementia with Lewy bodies 4
• Never prescribe typical antipsychotics (haloperidol) or atypical antipsychotics without specialist guidance if DLB is suspected, as these can cause severe neuroleptic sensitivity reactions with increased mortality risk 4

What NOT to Prescribe

• No evidence supports aspirin, statins, NSAIDs, hormones, or dietary supplements for cognitive benefit in Alzheimer's disease 2
• Gonadal steroids provide no benefit in global cognitive or physical function in persons with mild to moderate dementia or MCI 7

Essential Non-Pharmacologic Interventions

Caregiver education and support should accompany all pharmacologic treatment. 2

• Exercise, group cognitive stimulation therapy, and psychoeducational interventions for caregivers are recommended 7
• Evaluate for safety risks including wandering, falls, medication management, driving ability, and ability to live independently 4

Critical Pitfalls to Avoid

• Do not assume all short-term memory loss in elderly patients is Alzheimer's disease—trauma, substance abuse, metabolic disturbances, and delirium are common and require different management 1, 3
• Do not prescribe cholinesterase inhibitors for delirium or acute confusional states, which are transient and potentially reversible 3
• Do not use memantine as first-line treatment for mild dementia—it is indicated for moderate to severe disease 2, 6
• Do not continue donepezil indefinitely without reassessing response—if deterioration continues at the pretreatment rate after 6-12 months, discontinue and consider alternatives 2