What are potentially inappropriate medications (PIMs)?
Potentially inappropriate medications (PIMs) are drugs that pose an increased risk of adverse events, particularly in specific patient populations such as older adults. The risk of harm from these medications often outweighs the potential clinical benefit, especially when safer or more effective alternatives are available. This is largely due to age-related physiological changes that alter how drugs are absorbed, distributed, metabolized, and eliminated by the body.
For example, older adults often experience a decrease in kidney function and muscle mass, as well as an increase in body fat. These changes can lead to higher concentrations of certain drugs in the body and a prolonged half-life, increasing the risk of toxicity and side effects. This issue is further compounded by polypharmacy, where patients take multiple medications simultaneously, leading to complex drug-drug interactions.
Several criteria have been developed by medical experts to help healthcare providers identify and avoid PIMs. The most prominent of these are the AGS Beers Criteria®, developed by the American Geriatrics Society (AGS), and the STOPP (Screening Tool of Older Person's Prescriptions) criteria, often used in Europe. These regularly updated guidelines are crucial resources for promoting safe prescribing practices, although they do not replace individual clinical judgment.
Common examples of PIMs
PIMs span many drug classes, with central nervous system drugs, cardiovascular medications, and nonsteroidal anti-inflammatory drugs (NSAIDs) being among the most common. Below are some common examples of PIMs and their associated risks, particularly for older adults:
- Anticholinergics: First-generation antihistamines (like diphenhydramine) and some antidepressants (like amitriptyline) have strong anticholinergic properties. They can cause confusion, sedation, constipation, and dry mouth.
- Benzodiazepines: These drugs, used for anxiety and insomnia, increase the risk of falls, fractures, and cognitive impairment in older adults due to increased sensitivity and slower metabolism.
- “Z-drugs” (non-benzodiazepine hypnotics): Medications like zolpidem are used for sleep but carry risks similar to benzodiazepines, including confusion, falls, and delirium.
- NSAIDs: Long-term use of NSAIDs, such as indomethacin, can increase the risk of gastrointestinal bleeding, ulcers, and kidney damage, especially in older adults.
- Muscle Relaxants: Drugs like carisoprodol and cyclobenzaprine can cause sedation and confusion, raising the risk of falls and other injuries.
- Antipsychotics: In older adults with dementia, these medications can increase the risk of stroke, cognitive decline, and death, and should be avoided for behavioral problems unless non-pharmacologic interventions have failed.
- Peripheral Alpha-1 Blockers: Often used for hypertension, these drugs can cause orthostatic hypotension (a sudden drop in blood pressure when standing), leading to dizziness and falls.
- Sliding-Scale Insulin: This regimen, where insulin is dosed based on current blood sugar levels without long-acting insulin, poses a higher risk of hypoglycemia (low blood sugar).
Why are PIMs a major concern in geriatric care?
Because older adults frequently have multiple chronic conditions (multimorbidity) and take several medications (polypharmacy), they are disproportionately affected by PIMs. The side effects and adverse events from PIMs, such as falls and cognitive decline, can lead to increased hospitalizations, reduced quality of life, and higher healthcare costs.
Furthermore, the prescribing of PIMs can be a sign of systemic issues, such as a lack of communication between different healthcare providers or insufficient training in geriatric pharmacology. Deprescribing, the process of reducing or stopping medications that are potentially inappropriate, is increasingly recognized as a strategy to mitigate these risks and improve outcomes.
PIM Comparison: Beers Criteria vs. STOPP/START
Two widely used tools, the American Geriatrics Society (AGS) Beers Criteria® and the STOPP/START criteria, guide healthcare providers in identifying inappropriate medication use, especially in older patients. While both aim to improve patient safety, they differ in their scope and focus.
| Feature | AGS Beers Criteria® | STOPP/START Criteria |
|---|---|---|
| Primary Focus | Explicit list of medications to be avoided or used with caution in older adults, based on risks that outweigh benefits. | Identifies both potentially inappropriate prescriptions (STOPP) and potential prescribing omissions (START). |
| Geographic Origin | Developed in the United States and widely used there. | Developed in Europe and commonly used there and elsewhere internationally. |
| Content Scope | Categorizes PIMs based on drugs to avoid, drugs to use with caution, drug-drug interactions, and drug-disease interactions. Includes dosage adjustments for kidney function. | Addresses a wider range of prescribing issues beyond just high-risk drugs, including duplicate therapy and drug-disease interactions. Includes START criteria for medication omissions. |
| Level of Detail | Lists specific drugs or drug classes to avoid, often with specific dosing or duration limits. | Arranged by physiological system (e.g., cardiovascular, respiratory) and identifies problems within those categories. |
| Key Strength | Provides clear, specific guidance on high-risk medications and their associated adverse effects (e.g., sedation, falls). | Offers a more comprehensive approach by identifying both overprescribing and underprescribing, providing a more holistic medication review. |
| Limitations | Primarily focused on avoiding medications, with less emphasis on medications that may be missing. Explicit criteria may not fit every individual patient case. | While comprehensive, it may be more complex for providers to apply and requires a thorough review of the patient's entire medication list. |
How to reduce the risk of potentially inappropriate medications
Patients and caregivers can take several proactive steps to minimize the risks associated with PIMs:
- Maintain an up-to-date medication list: Keep a current list of all prescription medications, over-the-counter drugs, vitamins, and supplements. Share this list with all healthcare providers to help them identify potential interactions and duplications.
- Ask questions: When a new medication is prescribed, ask your healthcare provider if it is on a list of potentially inappropriate medications (like the Beers Criteria) and whether safer or more effective alternatives are available.
- Discuss deprescribing: If you or a loved one takes multiple medications, discuss deprescribing with your doctor. This process involves a systematic review to identify and safely stop medications that are no longer necessary or may cause harm.
- Communicate side effects: Be vigilant in monitoring for new symptoms or side effects, such as confusion, dizziness, or stomach problems. Report any concerns to your healthcare provider promptly.
- Collaborate with pharmacists: Pharmacists are medication experts and can be valuable partners in reviewing your medications for potential issues. They can check for drug interactions and help ensure appropriate dosages.
Conclusion
Potentially inappropriate medications are a significant concern, particularly for older adults, as they increase the risk of serious health problems like falls, cognitive decline, and hospitalization. Tools such as the Beers Criteria and STOPP/START criteria serve as essential guides for healthcare professionals to identify and mitigate these risks. However, patients and caregivers also play a vital role in preventing harm through active participation in their medication management. By maintaining comprehensive medication records, engaging in open communication with healthcare providers, and considering deprescribing when appropriate, patients can significantly reduce their exposure to these harmful drugs and improve their overall health outcomes.
