To stay on top of a couple nagging health problems you take a few maintenance meds, and maybe even pop some supplements to fill in any nutritional gaps. You're the picture of health, right?

Kinda. Unfortunately, even the healthiest among us seem to forget that mixing meds, supplements, and over-the-counter products without talking it over with a doc or a pharmacist can lead to potentially deadly drug interactions. And apparently, the number of older adults getting themselves into these risky situations is on the rise. The number of adults ages 62 to 85 using potentially dangerous combinations of prescription meds, OTC pills, and supplements doubled between 2005 and 2011, according to research published in JAMA Internal Medicine. (Tired of feeling miserably out of shape? Get your body back in just 10 minutes a day with this reader-tested strategy!

Prescription drugs in general have become more accessible for patients in this age group in recent years, said study author Dima Qato, PharmD, MPH, PhD, an assistant professor at the University of Illinois's College of Pharmacy. Guidelines promoting the use of certain drugs have also expanded to include a broader range of patients, she says. And there's been a dramatic increase in the use of supplements during this time period, too, without a whole lot of education about supplement safety. And that's a problem, because those supplements can change how your prescription med works, said Papatya Tankut, RPh, vice president of pharmacy affairs for CVS Health. (If you’re exhausted more often than not, check out these 7 reasons you’re tired all the time.)

Qato and her team identified a number of combinations that need to be considered carefully. Here are a few you should be aware of. (And you know this, but be sure to read the label on any Rx you take, and chat up your pharmacist about known drug interactions.)

Prescription drug: Warfarin
Doesn't mix well with: Garlic supplements, omega-3 supplements, naproxen, aspirin (See which kind of milk has 50 percent more omega-3s.)

The prescription blood thinner reduces your risk of clots, but garlic and omega-3 supplements as well as OTC pain pills containing naproxen (the active ingredient in Aleve) or aspirin have a similar effect, leading to an increased risk of bleeding. People sometimes think adding another med with the same powers will simply boost the effects of their Rx med, but prescription doses are carefully calculated, so taking anything extra can overdo it, said Madelyn Fernstrom, PhD, CNS, health and diet editor at NBC News and the author of “Don't Eat This If You're Taking That: The Hidden Risks Of Mixing Food And Medicine.”

"You can have internal bleeding if you don't have enough clotting activity," she said. "Every little bit of damage within your body will take longer to repair."

Don't stress too much about eating garlic or fish, though, as the concentrated amounts of the active ingredients in supplements are gigantic compared to what's found in actual foods, she said. (See your abs again with these 9 proven ways to lose belly fat.)

Prescription drug: Lisinopri
Doesn't mix well with: Potassium supplements
This blood pressure med is known as an ACE inhibitor, and it works by relaxing blood vessels to allow for better flow. Often, people with high blood pressure hear that potassium can help regulate BP and think they must not be getting enough, Fernstrom says. (Eat down your BP with these 13 power foods that lower blood pressure naturally.) However, supplementing can interfere with the action of your blood pressure 'script, which already retains some potassium in the process, she says. Too much potassium building up in your blood can result in muscle fatigue, an abnormal heartbeat, and even paralysis.

Prescription drug: Statins
Don't mix well with: Vitamin B3, warfarin, amlodipine
Statins and B3, also known as niacin, used to be recommended together if you had high cholesterol, but it turns out that taking statins and large doses of niacin can lead to muscle tissue disease or even kidney failure. (And those super-large doses of niacin could lower your cholesterol too much.) Recently, the FDA decided to take back its recommendation to use these two together anyway. Some heart patients may benefit from taking prescription blood-thinners alongside statins, Tankut said, but this combo may also cause muscle pain or weakness, as well as kidney failure.

"When your dose is adjusted, however, the benefits can outweigh the risks if your physician is monitoring you," she said.

Prescription drug: Clopidogrel bisulfate
Doesn't mix well with: Aspirin, naproxen
This prescription med keeps blood clots at bay, but what happens if you, say, have a headache, and want to pick up an OTC painkiller like aspirin or naproxen? Combining the two, because they're both anti-inflammatories and essentially mimic the same process, Tankut said, can increase your risk for internal bleeding. Luckily, most people are aware of that risk if they're on any kind of blood thinner, even if it's just a daily aspirin, Tankut said—but it's worth a friendly reminder.

This article originally appeared on Prevention.com.