Medications for Older Adults: Safety & Special Considerations

Adults aged 65 and older take more medications than any other age group — roughly 90% take at least one prescription drug, and more than one-third take five or more [1]. Aging changes how the body processes drugs, making older adults more vulnerable to side effects, drug interactions, and adverse reactions [2]. Understanding these changes is key to safe medication use in later life. How Aging Changes Drug Response The body undergoes several changes with age that affect how medications work [2][3]. Kidney function declines — by age 75, many people have lost 25-50% of their kidney function, meaning drugs cleared by the kidneys accumulate to higher levels [3]. Liver metabolism slows, reducing the first-pass effect and the rate at which many drugs are broken down. Body composition shifts — increased body fat and decreased lean muscle mass and total body water alter how drugs distribute throughout the body [2]. Fat-soluble drugs (like diazepam) have longer durations of action because they accumulate in fatty tissue. Water-soluble drugs (like lithium) may reach higher blood concentrations because of reduced water volume. The brain also becomes more sensitive to certain drugs, especially CNS depressants, increasing fall risk and cognitive effects [2][3]. Polypharmacy and Its Risks Polypharmacy — taking five or more medications simultaneously — is common in older adults and is one of the leading risk factors for adverse drug reactions [1][4]. Each additional medication increases the risk of drug interactions exponentially. Older adults taking 5-9 medications have a 50% chance of experiencing an adverse interaction, and those taking 20+ medications have a near-certain risk [4]. Polypharmacy also increases the risk of prescribing cascades — where a side effect is treated with another medication, whose side effects are treated with yet another [1]. The Beers Criteria: Drugs to Avoid in Older Adults The American Geriatrics Society maintains the Beers Criteria, a list of medications that are potentially inappropriate for older adults [5]. Key categories include: first-generation antihistamines (diphenhydramine, chlorpheniramine) — strong anticholinergic effects increase confusion and fall risk. Benzodiazepines (alprazolam, diazepam, lorazepam) — increased risk of falls, fractures, cognitive impairment, and paradoxical agitation. Long-acting sulfonylureas (glyburide) — increased hypoglycemia risk. NSAIDs (ibuprofen, naproxen) used chronically — increased GI bleeding and kidney injury risk. Muscle relaxants (cyclobenzaprine, methocarbamol) — poor efficacy in older adults with high anticholinergic burden [5]. Preventing Medication Problems Schedule regular "brown bag" medication reviews — bring all medications (including OTC and supplements) to your doctor or pharmacist in a bag for comprehensive review [1][4]. Ask about deprescribing — the systematic process of reducing or stopping medications that may no longer be needed or that pose more risk than benefit [4]. Use one pharmacy for all medications to enable automatic interaction screening. Use a pill organizer or medication management app to prevent missed or double doses. Stay hydrated and maintain regular kidney function monitoring if taking drugs cleared by the kidneys [3].