Older adults with dementia process medications differently due to age-related physiological changes and the specific effects of dementia on the brain and body. These differences affect how drugs are absorbed, distributed, metabolized, and excreted, often leading to increased sensitivity to medications and a higher risk of adverse effects compared to younger adults or older adults without dementia[1].
As people age, several key pharmacokinetic processes change:
– **Absorption:** While gastrointestinal absorption is generally less affected by age, changes in gastric pH, motility, and blood flow can alter the rate at which some drugs enter the bloodstream.
– **Distribution:** Aging typically leads to decreased total body water and lean body mass, with increased body fat. This alters the volume of distribution for hydrophilic and lipophilic drugs, potentially increasing the concentration and duration of action of certain medications.
– **Metabolism:** Hepatic metabolism slows with age due to reduced liver size and blood flow, especially affecting phase I metabolic reactions (oxidation, reduction). This can prolong the half-life of drugs metabolized by the liver, increasing the risk of accumulation and toxicity.
– **Excretion:** Renal function declines with age, reducing clearance of renally excreted drugs. This is particularly important for medications with narrow therapeutic windows.
In dementia, these changes are compounded by disease-specific factors. For example, dementia can impair blood-brain barrier function and alter neurotransmitter systems, which may affect drug sensitivity and response, especially for central nervous system (CNS) active drugs like antipsychotics, sedatives, and cholinesterase inhibitors[1][2].
Older adults with dementia are often prescribed multiple medications (polypharmacy) to manage cognitive symptoms, behavioral and psychological symptoms of dementia (BPSD), and comorbid conditions. Polypharmacy increases the risk of drug-drug interactions and adverse drug reactions, which can worsen cognitive impairment or cause other complications such as falls, sedation, or cardiovascular events[1][2].
Antipsychotic medications, commonly used to manage BPSD such as agitation, aggression, hallucinations, and sleep disturbances, illustrate these challenges. Although they can be effective, antipsychotics carry significant risks in dementia patients, including increased chances of stroke, pneumonia, worsening cognition, and mortality. Clinical guidelines recommend using the lowest effective dose for the shortest duration possible, ideally 1 to 3 months, and only for severe symptoms that pose harm. However, studies show many dementia patients remain on these drugs longer and at higher doses than recommended, increasing their risk of adverse effects[2].
Emerging treatments and considerations also highlight the complexity of medication processing in dementia. For instance, new anti-amyloid therapies aim to slow Alzheimer’s disease progression but carry risks such as brain swelling and microbleeds, requiring careful patient selection and monitoring[4]. Additionally, research into metabolic dysfunction in dementia has led to interest in GLP-1 receptor agonists (used in diabetes) as potential agents to protect brain health by improving insulin signaling in the brain, which is often impaired in Alzheimer’s disease[3].
Effective medication management in older adults with dementia requires personalized approaches that consider altered pharmacokinetics, increased drug sensitivity, polypharmacy risks, and the unique challenges of dementia symptoms. Caregivers play a crucial role in managing complex medication regimens, often employing diverse strategies that blend technology and physical methods to ensure adherence and safety[5].
In clinical practice, this means starting medications at low doses, titrating slowly, regularly monitoring organ function (especially liver and kidney), and closely observing for side effects. Nonpharmacological interventions should be prioritized when possible to minimize medication burden and adverse effects[1].
—
**Sources:**
[1] Navigating Medication Management for Psychiatric Conditions in Seniors, The Supportive Care
[2] UK dementia patients may be taking antipsychotics for too long, UCL / Lancet Psychiatry
[3] Prevention of Dementia with GLP-1 Medications: Benefits & Insights, Stages of Life Medical Institute
[4] Controversial New Alzheimer’s Drugs Offer Hope—But at a High Cost, Nature
[5] Caregiver personas offer insights for improving dementia medication management, News Medical
