4 Types of OTC Meds That May Cause Serious Side Effects

The body metabolizes many drugs differently when you’re older. Treat your symptoms and stay safe with this guide.

Most of us reach for over-the-counter (OTC) medication without giving it too much thought. When you have a throbbing headache, you pop a few Advil. When you’re feeling constipated, you chew on some Ex-Lax. And when you have a lousy cold, you grab whatever bottle promises the fastest relief.

While there’s nothing necessarily wrong with using these and other types of OTC drugs, it’s a mistake to think that there’s no downside. “OTC drugs are remarkably safe when used as directed, but they are not harmless,” says Eric P. Brass, M.D., Ph.D., professor emeritus of medicine at David Geffen School of Medicine at UCLA. “These are real drugs, many of which were available by prescription only in past years,” he says. “You must read the labels carefully and follow all the directions.” (If you need help understanding labels, check out the FDA’s guide.)

You should also check with your doctor or pharmacist before taking an OTC medication, even though you don’t need a prescription to get it. Many drugs are metabolized differently in seniors—meaning your body might process it more slowly or quickly than it did when you were younger—which could lead to side effects if you don’t adjust the dosage for your age.

Additionally, older people are often already taking one or more medications for a chronic condition, and adding an OTC med to the mix without getting an expert’s okay could cause you to have a dangerous interaction. In fact, research published in JAMA Internal Medicine found that this problem has increased substantially since 2005, and that 15 percent of older adults may be at risk for a major drug-drug interaction.

The main takeaway is that OTC doesn’t equal safe, and just as with prescription meds, you need to have a health care provider guide you based on your age, personal health history, and other medications (including supplements) that you’re taking. With that said, here are a few categories of OTC meds you should be especially cautious about.

Category #1: Pain Relievers

“In older patients, I tend to recommend acetaminophen [Tylenol] because it causes less stomach upset and kidney issues compared to NSAIDs like ibuprofen [Advil or Motrin] or aspirin,” says Preeti Malani, M.D., chief health officer at the University of Michigan and director of the National Poll on Healthy Aging. The catch is that acetaminophen isn’t without its own risks: Taking too much is the leading cause of liver failure in the United States.

Dr. Malani’s advice: If you have kidney disease or gastrointestinal issues, acetaminophen may be a safer bet. But if you have liver problems or are at risk for them, ibuprofen may be a better option—provided you don’t have a bleeding disorder and aren’t already taking a blood thinner like warfarin (Coumadin). And no matter what you choose, stick with the lowest possible dose to minimize the risk of side effects. “A little can go a long way,” Dr. Malani says. “People tend to underestimate how effective these drugs are.”

If you’re in chronic or severe pain, it’s smart to check in with your doctor for a proper diagnosis and treatment.

Category #2: Cold Medicine

These drugs are popular, but doctors remain wary. A major problem is that it’s easy to get too much by accidentally double-dosing yourself. Most cold formulas contain a combo of different active ingredients. If you don’t read the label carefully, you might not realize that the product contains a drug that you’re already taking separately, like aspirin for arthritis or heart disease.

Dr. Malani suggests that, whenever possible, older adults should avoid cold medication entirely and opt for non-drug remedies. Try using a saline nasal rinse, taking a hot shower, or running a humidifier to soothe sinuses and thin mucus. “None of the cold drugs work that well, and the cost, in terms of side effects, can be significant.”

If you’re really desperate for extra relief, buy a single-ingredient product. That way, you treat your most pressing problem without making yourself vulnerable to side effects of other drugs you don’t really need.

Which one should you choose? Decongestants like pseudoephedrine (Sudafed) may help if you’re super-stuffy, but they’re a bad choice for anyone with high blood pressure, irregular heartbeat, or a seizure disorder, says Thomas Weida, M.D., chief medical officer at the University of Alabama College of Community Health Sciences.

If you’re sneezing and your nose runneth over, you may benefit from an antihistamine like diphenhydramine (Benadryl) or brompheniramine (Dimetapp), but they can make you sleepy. This side effect can get worse as you get older, because you don’t metabolize them as quickly. “And if you also have sleep apnea, you’re really at risk of a car accident or a fall,” Dr. Weida says, so it’s best to avoid them. (Note: Non-sedating antihistamines that treat allergies, like Zyrtec and Claritin, generally don’t work well for colds.)

Category #3: Heartburn Drugs

Again, there’s no one medicine that’s perfect for everyone. While proton pump inhibitors (PPIs) like omeprazole (Prilosec), esomeprazole (Nexium), and lansoprazole (Prevacid) have come under recent scrutiny, thanks to studies linking them to bone fractures and dangerous infections, they may still be beneficial for people with severe reflux that can’t be remedied with lifestyle changes alone.

And while antacids like Tums are often thought of as safer options—and they’re certainly less potent—the selection must be individualized. Tums contain calcium carbonate, and if you’re taking thyroid medication or certain antibiotics, it could interfere with their absorption, Dr. Malani says.

Milk of Magnesia can also be problematic. “The mineral can impact the electrolyte balance in your body,” Dr. Malani says. Take too much of it, Dr. Weida adds, and you can end up with diarrhea.

Dr. Weida is also concerned that many people take heartburn drugs for a long time without consulting a doctor, and that they could be masking a more serious issue. “It could be an ulcer or even something like cancer,” he says, so don’t self-treat for too long without getting checked out.

Category #4: Laxatives

If you’re frequently backed up, you’re hardly alone. “Older people are prone to constipation, because over time the gut doesn’t have the same motility,” Dr. Malani says. While any sudden change in bowel habits warrants a trip to the doctor’s office, it’s not unusual to need some extra help to stay regular. But with so many options on the market, it can be hard to know what to choose.

Step one, Dr. Malani says, is to improve your diet by eating more fruits and vegetables. Fiber supplements, like Metamucil, also tend to be helpful without causing side effects.

If that’s not cutting it, you may be tempted to take a stimulant like Ex-Lax or Dulcolax, but doctors don’t recommend these for long-term use. “Once in a while it’s okay, but these drugs can be habit-forming because your gut gets used to them,” Dr. Malani says. They also have the potential to interact with heartburn drugs you may be taking.

The safest long-term option is Miralax, Dr. Malani says. It draws water from your body into the colon, which softens stool and makes it easier to go. It’s even safe for kids, she says.

Dealing with the opposite problem? Loperamide (Imodium) may do the trick for diarrhea, but side effects may include gas and bloating, Dr. Weida says.

The Bottom Line

Before you take any OTC meds, check with your doctor or pharmacist. They can help you figure out the best way to treat your symptoms without any unwanted or potentially dangerous side effects. Be sure to let them know all the medications you take, including prescriptions, other OTC drugs, and supplements.