We are living in the age of prescription drugs. They can turn once-fatal diseases into manageable, chronic conditions. But especially for older adults, many of whom take five or more medications each day, they can cause illness or even death.

A new study by Judith Garber and Shannon Brownlee of the Lown Institute, estimate that as many as 10 million older adults—about one of every five seniors– had some kind of adverse drug reaction in 2018. They calculate that five million older adults were treated for a negative reaction to a medication and 280,000 were admitted to hospitals, at a cost of  $3.8 billion. More than half of those hospitalized were older adults. Over the next decade, 160,000 people will die from adverse reactions to prescription drugs.

The most at risk: Those taking five or more medications were nearly twice as likely to seek medical care than those taking one or two meds. Sometimes, these events are caused by the side effects of an individual drug. But often, they result from interactions among multiple drugs. Older adults taking many different pills are far less likely to take them as prescribed—either because they cannot manage them all or because they ration costly meds to save money.

Pharmaceutical drug use among seniors is a two-edged sword. On one hand, these medications can be extraordinarily beneficial. Statins, commonly prescribed for older adults, significantly reduce the risk of heart attacks and strokes by lowering cholesterol. Insulin and similar medications allow diabetics to live long and productive lives.

Yet diabetes medications are among the leading causes of adverse drug reactions. If they   lower blood sugar too much, they increase the risk of falls and confusion. Similarly, while blood thinners such as aspirin or warfarin can improve blood flow for patients with heart disease, they also increase risk of severe bleeding. Here is a list of medications that can be especially risky for older adults.

Unlike opiods, which often have been widely misused or inappropriately prescribed, many medications are appropriate. But they still come with risks.

There are many causes of excessive, and dangerous, prescription drug use among older adults.

Hyper-specialized doctors. The increasing specialization of medical care is a hallmark of modern medicine. The upside: your doctor may be a true expert in your condition. The downside: She may not know—or even care—about how the meds she prescribes interact with drugs ordered by other physicians. For instance, your cardiologist may see her job as only treating your heart disease. She may not think about how your heart medicine interacts with your arthritis drugs.

Prescription cascades. Many of us have seen this one: A doctor prescribes a drug for one condition. The drug itself creates a new problem, and the doctor’s solution is yet another medication.

The Lown study includes a tragic case study: A man was given steroids to treat Crohn’s disease, then given antibiotics to treat the effects of the steroids. The antibiotics caused nerve damage and pain so he was given multiple painkillers plus drugs to help him sleep. They caused diarrhea, which was treated with meds that damaged the patient’s kidneys, which raised his blood pressure, which required still more drugs. Before he died, the patient was taking 31 pills every day, most to treat the effects of others.

Poor research. The negative effects on older adults of individual drugs or interactions among multiple drugs are poorly researched. Because drug trials often are focused on young adults, physicians may be unaware for years of the effects on seniors. One solution may be better monitoring of prescriptions once they are ordered.

What can consumers do?

Before taking a new drug, ask your doctor about its side effects, especially for older adults. If he is not giving you clear or satisfactory answers, get another doctor.

If your health status changes after you begin taking a new drug, check to be sure the medication itself isn’t the cause. Family members should especially watch for symptoms of confusion. This can be especially important for people who already have some cognitive impairment. Physicians often mistake drug-related confusion or delirium for dementia. They are not the same.

If you are taking multiple medications (including over-the-counter drugs), insist that one of your doctors—probably your primary care doc—act as quarterback. And if you find yourself getting a cascade of drugs—each to treat the effects of another—call a time-out. Ask your doctors to think about addressing this issue by ending or changing the medication that started the cascade in the first place instead of merely prescribing more drugs.

Finally, consider talking to a board-certified geriatric pharmacist or a consulting pharmacist. They may know much more than many physicians about complex drug interactions.