What is the most common adverse drug effect seen in the elderly?

Oct 5, 2025 3 min read •

Geriatrics Pharmacology Patient Safety

According to the American Academy of Family Physicians, falls are one of the most common and serious manifestations of adverse drug events in older adults, accounting for 24% of such events in a study cited. Addressing the question, "What is the most common adverse drug effect seen in the elderly?" requires understanding how age-related physiological changes increase vulnerability to adverse reactions and recognizing that several common drug effects pose significant, widespread risks to this population.

Quick Summary

Falls, cognitive decline, and oversedation are frequent and significant adverse drug effects in older adults due to age-related physiological changes and polypharmacy. Common medications affecting the central nervous system, like benzodiazepines and certain antidepressants, often contribute to these issues. Risk management includes regular medication reviews and deprescribing strategies.

Key Points

Falls and Orthostatic Hypotension: Falls are a prevalent and serious adverse drug event, often triggered by medication side effects like dizziness, sedation, and sudden drops in blood pressure.
Cognitive Impairment and Delirium: Medications can cause confusion, memory loss, and acute delirium, which can be misattributed to dementia.
Oversedation and Drowsiness: Many medications, particularly those affecting the central nervous system, cause excessive drowsiness and reduced alertness, increasing the risk of accidents.
Gastrointestinal Issues: Common and sometimes severe adverse effects include constipation, nausea, and an increased risk of serious gastrointestinal bleeding, especially with NSAIDs and anticoagulants.
Polypharmacy is a Key Risk Factor: The concurrent use of multiple medications (polypharmacy) is highly common in older adults and exponentially increases the risk of drug-drug interactions and adverse effects.
Age-Related Physiological Changes: The aging process itself changes how the body handles medications, affecting drug distribution, metabolism, and elimination, which can lead to dangerously high drug levels.
Prevention through Deprescribing: Regular medication review and the process of safely reducing or stopping unnecessary medications (deprescribing) is a crucial strategy for mitigating adverse drug effects.
Psychotropic Medications Are Common Culprits: Medications used for anxiety, depression, and insomnia, such as benzodiazepines and antidepressants, are frequently implicated in falls and cognitive issues.

Age-Related Changes Exacerbate Medication Risks

Older adults are uniquely susceptible to adverse drug effects due to several factors related to the aging process. The body's pharmacokinetics—the way it absorbs, distributes, metabolizes, and excretes drugs—changes significantly with age. A decrease in total body water and an increase in body fat alter drug distribution, potentially leading to higher concentrations of water-soluble drugs and longer half-lives for fat-soluble drugs. Additionally, declining kidney and liver function can reduce drug clearance, causing medications to accumulate to toxic levels. These physiological changes, combined with a higher prevalence of multiple chronic conditions and polypharmacy (the use of multiple medications), create a perfect storm for adverse drug reactions.

The Most Common Adverse Drug Effects

While a variety of side effects can occur, several stand out as particularly common and problematic in the elderly population due to their severity and impact on quality of life. Falls, cognitive impairment, and oversedation are frequently cited as the most common adverse drug effects.

1. Falls and Orthostatic Hypotension

Falls are arguably the most common and dangerous adverse drug event among the elderly, often leading to serious injuries like fractures. Medications contributing to falls include psychotropics (antidepressants, benzodiazepines), cardiovascular drugs causing orthostatic hypotension, opioids, and anticholinergics.

2. Cognitive Impairment and Delirium

Medication-induced cognitive issues are often misdiagnosed. Delirium, acute confusion, and memory problems are frequent adverse effects, particularly with anticholinergics, benzodiazepines, and opioids.

3. Oversedation

Excessive drowsiness from medications is common, increasing accident risk. Common culprits include benzodiazepines, opioids, and antihistamines.

4. Gastrointestinal Issues

Gastrointestinal side effects such as constipation (from opioids, anticholinergics) and serious bleeding (from NSAIDs, anticoagulants) are common.

Comparison of Common Adverse Drug Effects

A table comparing common adverse drug effects including causes for concern, common culprit medications, and prevention strategies can be found on {Link: NCBI https://pmc.ncbi.nlm.nih.gov/articles/PMC4594722/}. This table details information on falls, cognitive impairment, oversedation, and gastrointestinal bleeding.

Managing and Preventing Adverse Drug Effects

Managing and preventing adverse drug effects in older adults is crucial for patient safety and quality of life. Strategies include:

Regular Medication Reviews: Healthcare providers should regularly review all of a patient's medications to identify potential interactions and inappropriate prescriptions. This is especially critical during transitions of care.
Deprescribing: Carefully tapering or discontinuing medications that are no longer beneficial can significantly reduce adverse reactions. A team-based approach can facilitate this.
Using the Beers Criteria: Clinicians can use tools like the American Geriatrics Society's Beers Criteria to guide prescribing decisions and minimize risks.
Patient and Caregiver Education: Educating patients and their caregivers on potential side effects is vital for early detection. Lack of awareness can lead to medication errors or delayed reporting of symptoms.
Monitoring and Communication: Careful monitoring of a patient's functional and cognitive status is essential. Healthcare providers should have a low threshold for considering an adverse reaction as the cause of new symptoms like confusion, dizziness, or falls. Strong communication among healthcare providers, patients, and families is key.

Conclusion

While no single adverse drug effect can be definitively labeled the "most common" without context, falls, cognitive impairment, and oversedation are consistently identified as the most frequent and impactful in the elderly population. These issues stem from a combination of age-related physiological changes, multiple chronic conditions, and the high prevalence of polypharmacy. Proactive strategies, including regular medication reviews, deprescribing, and patient education, are critical for mitigating these risks and improving the safety and quality of life for older adults on medication. Open communication among all members of the care team is essential for successfully navigating the complexities of geriatric pharmacology.

Disclaimer: This information is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional for personalized medical guidance.

Additional resources

HealthInAging.org: This resource from the American Geriatrics Society offers information on medications and their effects on older adults.
National Institute on Aging: The NIA website provides information on medication safety for older adults and covers topics like the dangers of polypharmacy.

Frequently Asked Questions

Medications frequently causing adverse effects in older adults include sedatives like benzodiazepines, opioids for pain, anticholinergics for bladder control, antidepressants, and some cardiovascular drugs.

It can be difficult to differentiate, as drug side effects often mimic other age-related conditions like confusion, dizziness, and fatigue. Any new or worsened symptom following a medication change should be discussed with a doctor, as clinicians should have a high suspicion for adverse reactions.

Medications are a significant contributor to falls because many common drugs cause side effects that impair balance and stability. These include dizziness, sedation, and a drop in blood pressure (orthostatic hypotension), which are common effects of psychotropic and cardiovascular drugs.

Polypharmacy refers to the use of multiple medications, often five or more, which is common in older adults with multiple health conditions. This significantly increases the likelihood of harmful drug-drug interactions and cumulative adverse effects.

Yes, through a process called deprescribing, in which a healthcare provider systematically reduces or discontinues medications that are no longer necessary or beneficial. You should never stop taking medication without a doctor's supervision.

The Beers Criteria, developed by the American Geriatrics Society, is a guideline that lists medications considered potentially inappropriate for use in older adults. It helps healthcare providers minimize risks by highlighting drugs with adverse side effects or those where safer alternatives exist.

Aging leads to changes in pharmacokinetics, altering how drugs are absorbed, distributed, metabolized, and eliminated. A decrease in body water, increase in body fat, and reduced kidney and liver function can lead to higher, longer-lasting drug concentrations in the body.

Yes. Over-the-counter (OTC) drugs, such as certain antihistamines, can have significant anticholinergic and sedative effects that increase the risk of confusion and falls in older adults. It is important to discuss all medications, including OTCs, with a healthcare provider.

References

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.