High-risk medications (also called high-alert medications) are drugs that carry a heightened risk of causing serious harm or death when something goes wrong with their use. Errors with these drugs aren’t necessarily more common than with other medications, but the consequences are far more severe. A systematic review found that medication errors involving high-alert drugs resulted in outcomes classified as serious in up to 15.4% of cases and lethal in up to 1.9%.
The Institute for Safe Medication Practices (ISMP) maintains the most widely referenced list of these drugs, and separate criteria exist for older adults. Understanding which medications fall into this category, and why, can help you stay safer whether you’re managing your own prescriptions or helping a family member.
What Makes a Medication “High-Risk”
The defining feature isn’t that mistakes happen more often with these drugs. It’s that when a mistake does happen, the margin for harm is razor-thin. A tenfold dosing error with a blood thinner or insulin can be fatal, while the same type of error with a vitamin supplement likely causes no harm at all. High-risk medications tend to share certain traits: a narrow window between a dose that helps and a dose that hurts, complex dosing that depends on multiple patient factors, or effects that are difficult or impossible to reverse once they take hold.
Blood Thinners
Anticoagulants like warfarin and the newer direct oral anticoagulants (often called DOACs) are among the most commonly cited high-risk medications. Their entire purpose is to prevent blood clots, but too much anticoagulation causes dangerous bleeding, and too little lets clots form. Getting the dose right is particularly challenging with DOACs because the optimal amount depends on the reason you’re taking it, your kidney function, body weight, and age.
Warfarin requires regular blood tests to check how well it’s working, giving doctors a measurable number to adjust. DOACs don’t have that kind of routine monitoring, which means patients need to be especially vigilant about taking doses on time. Because DOACs leave your system quickly, even missing a single dose can leave you unprotected against clots. Interruptions from skipped doses, insurance gaps, or upcoming medical procedures all create windows of risk that need careful management.
Insulin
All forms of insulin, whether injected or given intravenously, are classified as high-alert medications. More than half of reported insulin errors involve a patient receiving the wrong dose or no dose at all, directly threatening blood sugar control. About 10% of overdose events reported to one state safety authority involved a tenfold overdose, often caused by sloppy handwriting or confusing abbreviations (the letter “U” for “units” being misread as the number “0,” turning 8 units into 80).
Concentrated insulin creates additional danger. A patient using high-strength insulin with a standard syringe might tell a healthcare provider they take “40 units” because that’s what the syringe markings show, when they’re actually administering 200 units due to the higher concentration. Repeated injections can also “stack” insulin’s effect, causing prolonged and dangerous drops in blood sugar that are harder to correct than a single episode.
Opioid Pain Medications
Opioids suppress pain signals in the brain, but they also suppress the drive to breathe. This is the primary cause of death in opioid overdoses: the brain essentially forgets to send breathing signals to the lungs. Opioids also impair the upper airway, making obstructive breathing pauses more likely even at lower doses.
Fentanyl is roughly ten times more potent than morphine, meaning a tiny miscalculation in dosing produces outsized effects. The introduction of fentanyl and similar ultra-potent opioids into both medical settings and the illicit drug supply has driven a sharp rise in fatal overdoses from respiratory depression. In hospitals, combining opioids with sedatives or giving them to patients with existing breathing problems compounds the risk significantly.
Chemotherapy Drugs
Cancer-fighting medications are inherently toxic by design. They work by attacking rapidly dividing cells, which means they damage healthy tissue alongside tumors. The dosing calculations are complex, often based on body surface area and adjusted for organ function, and even small errors can cause devastating harm to the immune system, kidneys, liver, or heart. These drugs require special handling protocols to protect not just patients but also the healthcare workers who prepare and administer them. The CDC’s National Institute for Occupational Safety and Health maintains a dedicated list of hazardous drugs in healthcare settings, and the 2024 edition includes hundreds of agents requiring special precautions.
High-Risk Medications for Older Adults
People over 65 metabolize drugs differently. Slower kidney and liver function means medications stay in the body longer, and aging brains are more sensitive to drugs that cause sedation or confusion. The American Geriatrics Society publishes the Beers Criteria, a detailed list of medications that pose outsized risks specifically for older adults. Several major categories stand out.
Sedatives and Sleep Aids
Benzodiazepines like alprazolam, diazepam, and lorazepam carry increased risks of cognitive impairment, delirium, falls, fractures, and car accidents in older adults. The body breaks these drugs down more slowly with age, intensifying and prolonging their effects. Prescription sleep medications like zolpidem and eszopiclone (the “Z-drugs”) have a similar risk profile, including delirium and fractures, while providing only minimal improvements in how quickly someone falls asleep or how long they stay asleep.
Drugs With Anticholinergic Effects
A surprisingly large number of common medications block a chemical messenger called acetylcholine, producing side effects that hit older adults especially hard: confusion, dry mouth, constipation, blurred vision, and increased fall risk. This group includes first-generation allergy medications like diphenhydramine (the active ingredient in Benadryl), older antidepressants like amitriptyline, muscle relaxants like cyclobenzaprine, and certain bladder medications. Long-term use has been linked to higher rates of dementia.
NSAIDs
Over-the-counter pain relievers like ibuprofen and naproxen are familiar and seem harmless, but chronic use in older adults significantly raises the risk of gastrointestinal bleeding, stomach ulcers, and kidney damage. These risks climb further when combined with blood thinners or in people with existing kidney problems.
Other Flagged Medications
Several other drug classes appear on the Beers Criteria list for specific reasons:
- Sulfonylureas (diabetes pills like glimepiride and glyburide) can cause severe, prolonged drops in blood sugar and are linked to higher rates of cardiovascular events compared to newer diabetes medications.
- Proton pump inhibitors (heartburn drugs like omeprazole) should not be used for more than eight weeks in most cases due to risks of bone fractures, bone loss, and serious intestinal infections.
- Antipsychotics increase the risk of stroke, faster cognitive decline, and death in people with dementia.
- Digoxin, once a go-to heart medication, is no longer recommended as a first-line treatment because toxicity develops easily and safer options exist.
- Alpha-1 blockers like doxazosin and prazosin cause dangerous drops in blood pressure upon standing, leading to falls.
Staying Safer With High-Risk Medications
If you take any of these medications, the single most important thing you can do is understand exactly what you’re taking, why, and what the warning signs of a problem look like. For blood thinners, that means recognizing unusual bruising, blood in your urine or stool, or prolonged bleeding from cuts. For insulin, it means knowing the symptoms of low blood sugar: shakiness, sweating, confusion, and rapid heartbeat. For opioids, anyone in your household should know the signs of respiratory depression: slow or shallow breathing, bluish lips, and difficulty waking someone up.
Keep an accurate, complete medication list and bring it to every medical appointment. Many high-risk drug interactions happen when different doctors prescribe medications without knowing the full picture. For older adults taking multiple prescriptions, a pharmacist-led medication review can identify drugs that should be tapered, switched, or stopped entirely. These reviews have consistently been shown to reduce the number of inappropriate high-risk medications older adults take.