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Illustration: Dan Page

When you’re thinking about taking a new medicine, the list of possible side effects can look endless—and scary. Drug labels list an average of 70 (and as many as 525), according to one study.

“The more medications a person takes, the greater the chance at least one will cause an adverse effect,” says Michael Steinman, M.D., a professor of medicine in the geriatrics division at the University of California, San Francisco, School of Medicine. “Plus, medicines can interact with each other such that the combination causes problems.”

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How likely are you to experience side effects? In the U.S., about 750 people 65 and older are hospitalized each day because of them, according to a 2019 report from the Lown Institute, a nonpartisan think tank. Other research has found that almost 80 percent of people 70 and older experience at least one drug side effect in a six-month period.

What’s more, many people may not recognize problems such as muscle weakness, dizziness, lightheadedness, and unsteadiness as a side effect. “Sometimes, people think that these symptoms are just a sign of getting old,” Steinman says.

Here’s what you need to know to reduce the chance of harm.

Do Some Drugs Cause More Side Effects?

Yes. In a 2016 JAMA study, three types—blood thinners, diabetes medication, and opioid pain drugs—were responsible for an estimated 60 percent of emergency room visits by people 65 and older. If you take any of those, ask your doctor how to recognize and report the most serious side effects, and how you should be monitored to minimize risks.

What About Drugs That Are Brand New?

Drug ads often push the newest, most expensive products. But they usually don’t work better than older options—and may be less safe, says Joseph T. Hanlon, Pharm.D., M.S., a professor emeritus of geriatrics at the University of Pittsburgh. Before coming to market, new drugs are usually studied in short-term trials involving a narrow group of subjects. But serious side effects might not show up until a wider range of people have taken a drug for a longer time.

Years after their approval, new safety issues were detected in almost one-third of drugs approved by the Food and Drug Administration between 2001 and 2010, according to a 2017 study by researchers at Yale University. Except in rare cases, Hanlon says, “If a drug hasn’t been on the market for at least seven years, I don’t recommend it.”

Should You Worry About Side Effects Mentioned in Drug Ads?

Not really. Those ads—as well as the documents with tiny print that come with your prescription—list all of a drug’s major risks, and often many more minor effects, too. Most are unlikely to affect you, Steinman says. Instead of focusing on the ads, talk with your doctor and pharmacist about the side effects that concern you based on your medical history, he advises.

Can OTC Drugs Cause Side Effects Too?

Absolutely. For instance, regular long-term use of nonsteroidal anti-inflammatory drugs such as ibuprofen (Advil, Motrin) and naproxen (Aleve) can cause bleeding stomach ulcers, raise blood pressure, and increase the risk of a heart attack.

And dietary supplements can cause side effects on their own as well as interact with medications. So keep your pharmacist and other healthcare providers informed about any over-the-counter drugs or supplements you take regularly, says Paula Rochon, M.D., M.P.H., a professor of geriatric medicine at the University of Toronto.

Do Your Age and Gender Affect Your Risk?

Yes. People tend to take more medications as they get older, which puts them at a higher risk for side effects.

As you age, your liver and kidneys become less efficient at breaking down and removing medication from your body, Hanlon says. Even medication you’ve taken for a long time can start to cause problems.

In addition, women tend to be smaller than men. This means they may need a lower dose than men their age for certain medications, such as the sleep drug zolpidem (Ambien) and the blood thinner warfarin (Coumadin).

What Should You Do If You Think You Are Having a Side Effect?

First, notify your doctor. (Abruptly stopping some drugs can be harmful, so don’t quit without your doctor’s okay.) Some milder side effects are expected and may go away after a while.

For example, the feeling of fatigue some people get when starting medication for high blood pressure usually wears off over time, Hanlon says. But don’t endure discomfort long-term. “In most cases,” he says, “there are so many alternatives that you shouldn’t have to.”

It can be difficult to figure out whether a symptom is caused by a drug, an interaction between two or more drugs, an underlying health condition, or another medical problem. You may need to work with your healthcare provider to make several adjustments to your medication regimen to find what works for you.

The best experts for this kind of detective work, Hanlon says, are geriatricians and board-certified geriatric pharmacists, who have advanced training and experience in managing medication for seniors. The American Society of Consultant Pharmacists lists them by state on its Find a Senior Care Pharmacist page.

How Can You Reduce Your Risk of Side Effects?

Communicating with your healthcare providers is key, Steinman says. “I encourage my patients to ask questions, speak up, and let them know about any problems,” he says. And keep the following in mind.

Take fewer drugs if possible. Before starting a new one, ask about nondrug options. Some measures, such as psychological counseling for insomnia and physical therapy for back pain, can work as well as drugs—with far less risk.

Simplify your drug regimen. Making a mistake with timing or the dose can lead to serious adverse reactions. If you have trouble keeping track of what to take and when, ask your doctor or pharmacist to help you streamline your drug regimen.

Review your drugs regularly. At least once or twice a year, make an appointment with your doctor or pharmacist to go over everything you take or use, including prescription and over-the-counter medications, ointments, ophthalmic preparations, herbal preparations, and vitamins. Ask about possible drug reactions and whether there’s medication you no longer need.

Avoid “prescribing cascades.” That happens when doctors prescribe drugs to treat side effects of other drugs. “People should always ask the provider ‘Could this problem I’m experiencing be related to a drug I’m taking?’ ” Rochon says.

Can Side Effects Ever Have an Upside?

Drugs often affect the body in unexpected ways. Some of those unintended effects can even be beneficial.

For example, the blood pressure drug propranolol (Inderal) can help ease symptoms associated with stage fright. The diabetes drug metformin may lower LDL “bad” cholesterol. And some research suggests that getting a flu shot can also reduce your risk of a heart attack or stroke.

In many instances, researchers discover new uses for medication once they’ve been on the market for a while. Beta blockers, originally used to treat chest pain and high blood pressure, have become part of the standard treatment for heart failure. And different types of antidepressants may help treat certain forms of chronic pain.

Still, you should be cautious about taking a drug “off label”—that is, for a use not approved by the FDA. According to some research, people taking a drug off-label are more likely to have adverse effects.

When considering medication, ask your doctor whether the FDA has approved it for your condition and, if not, whether there’s good evidence that the drug will help and is safe.

Editor’s Note: This article also appeared in the May 2020 issue of Consumer Reports On Health