Millions of older Americans are taking prescription drugs in combinations that are extremely dangerous. Something as seemingly innocuous as taking a blood pressure medication with a statin…or taking a heart drug with an over-the-counter heartburn drug—even a nutritional supplement—could do irreversible harm.

What’s even more disturbing: The number of people taking these combos has nearly doubled in less than a decade, finds a new study. It’s now one in six—more than five million people.

Read on to learn the most dangerous drug combinations—and how to protect yourself or a loved one.


Between 2005 and 2006, University of Illinois researchers went into the homes, literally, of more than 2,000 adults between ages 62 and 85 (average age 71). They looked through their medicine cabinets to see what prescription medications, over-the-counter medications and dietary supplements they were taking. Five years later, they repeated the home drug inventory with a similarly representative group. The study was published in 2016.

Here’s what they found: We’re taking more drugs—and more supplements. The number of people taking more than five prescription medications—a threshold that makes adverse drug-drug reactions much more likely—went up from 31% to 36%. Use of supplements—especially omega-3 fish oil, vitamin D and coenzyme Q10—went up, too. Fish oil supplements alone went from 4.7% to 18.6%. These drugs and supplements may each play an important role in a patient’s treatment plan, but they open the door to adverse interactions.

To explore that, the researchers zeroed in on 15 specific combinations of prescription drugs with other drugs (both prescription and OTC) as well as with supplements. They were looking at combos that could cause serious, possibly life-threatening, adverse effects such as kidney failure, uncontrolled bleeding and heart attacks.

In 2005, the percentage taking such dangerous combinations was 8.4%. By 2011, it was 15.1%, a near doubling. The percentage taking two or more of these extremely dangerous combos nearly tripled—from 1.6% to 4.2%.


  • Most common dangerous drug-drug combo: Amlodipine (a calcium channel blocker for blood pressure) and simvastatin (a statin for cholesterol). When taken together, the result can be kidney failure, myopathy (severe muscle weakness) or rhabdomyolysis (a dangerous breakdown of muscle tissue). Over the course of the study, the percentage with this scary combo went up from 1% to 4%. Simvastatin or other statin medications taken with either niacin (to lower cholesterol) or warfarin (to prevent blood clots) also increases the same risks. While it’s possible to take both drugs together safely, it requires careful management of doses by a doctor, while keeping a close watch on possible side effects.
  • Another common dangerous combo: Many people were taking blood-thinning medications, such as clopidogrel (Plavix) or warfarin (Coumadin), and also taking other supplements or OTC drugs that can greatly increase the risk for uncontrolled bleeding or clotting. Major culprits: Omeprazole (Prilosec), a proton pump inhibitor for GERD…or aspirin…or naproxen (Aleve), an NSAID, for pain…or omega-3 fish oil…or garlic. Each of these can also “thin” the blood so the combination with Plavix can be dangerous.
  • Most common drugs and supplements involved in dangerous combos: Statins, blood thinners, NSAID painkillers and omega-3 fish oils. One contributor to the problem, according to the researchers—new guidelines that have led to more statins being prescribed to prevent heart attacks. More doctors are also prescribing fish oil supplements to patients, but many people also take these on their own—without realizing their interaction with other drugs they may be taking.
  • Frightening example: Plavix taken with Prilosec or an NSAID (aspirin, Advil, Aleve) is associated with increased risk for a heart attack or stroke—and death from cardiovascular causes. Despite this risk, nearly one million older adults now are regularly using Plavix in interacting combinations. In the five years of the study, Plavix use increased by 58% and aspirin use by 33%.

Don’t be a victim: Let your health-care provider know every drug—prescription or OTC—and every supplement that you’re taking. One key ally is your pharmacist, who is trained at spotting potential drug-drug or drug-supplement interactions.

Ask questions about every prescription you’re taking—is it really necessary? For example, there is a growing controversy over whether statins should be a first-line defense against heart attacks, and there is strong evidence that regular use of proton pump inhibitors (PPIs) is really bad for your heart. (For nonprescription alternatives to both statins and PPIs, see Bottom Line’s article, “When The Best Medicine Is Not a Drug.”) Be forthright about your supplements, too—fish oil supplements are natural blood thinners so combining them with prescription blood thinners is a really bad idea. Don’t let one of these drug interactions happen to you!