Last month, Caryn Isaacs went to see her primary care doctor for her annual Medicare wellness visit. A patient advocate who lives in Manhattan, Ms. Isaacs, 68, felt perfectly fine and expected a clean bill of health.
But her doctor, who’d ordered a variety of blood and urine tests, said she had a urinary tract infection and prescribed an antibiotic.
“The nurse said, ‘Can you take Cipro?’” Ms. Isaacs recalled. “I didn’t have any reason not to, so I said yes.”
There are actually plenty of reasons for older people to avoid Cipro and other antibiotics known as fluoroquinolones, which have prompted warnings from the Food and Drug Administration about their risks of serious side effects.
And there are good reasons to avoid any antibiotic when bacteria is detected in a urine culture in a patient who has no other signs of infection. So-called asymptomatic bacteriuria increases with age, but these women are not sick and don’t need drugs, so medical guidelines recommend against routine screening or treatment.
Yet Ms. Isaac’s prescription was hardly unusual. Despite ongoing campaigns by the Centers for Disease Control and Prevention and other public health groups, older Americans still take too many antibiotics.
Patients over age 65 have the highest rate of outpatient prescribing of any age group. A new C.D.C. study, published in the Journal of the American Geriatrics Society, points out that doctors write enough antibiotic prescriptions annually — nearly 52 million in 2014 — for every older person to get at least one.
Because the researchers used a national pharmacy database that tracked only outpatients, the study likely underestimates the problem. “The volume would be higher if you included hospitals and nursing homes and other long-term care settings,” said Katherine Fleming-Dutra, deputy director of the C.D.C.’s Office of Antibiotic Stewardship.
Glass-half-full types might be pleased to see that after climbing 30 percent from 2000 to 2010, antibiotic prescriptions for older adults leveled off between 2011 and 2014. “That’s potentially good news,” said Dr. Sarah Kabbani, an infectious disease specialist at the C.D.C. and lead author of the study.
But what public health advocates want to see is a decline, as has happened with young children, once the group most likely to use antibiotics.
“It’s hard to feel heartened about a plateau when overuse remains so prevalent,” said Dr. Caleb Alexander, co-director of the Johns Hopkins Center for Drug Safety and Effectiveness. “It’s as perennial as the grass.”
Antibiotic overuse contributes to a serious public health threat by creating drug resistance, as infectious bacteria adapt to the medications. Drugs then lose their effectiveness, forcing doctors to resort to more toxic, less potent, often costlier options. Two million Americans get antibiotic-resistant infections annually, the C.D.C. has reported, and 23,000 die from them.
Moreover, antibiotics interact badly with many of the other drugs older adults take, including such widely used medications as statins, blood thinners, kidney and heart medications. “The number of potential drug-drug interactions with antibiotics are vast,” Dr. Alexander cautioned.
Some antibiotics also have dismaying, even alarming, side effects in themselves. In 2013, the F.D.A. issued a warning about azithromycin, which in rare cases leads to dangerous heart arrhythmias.
But for more than a decade, the agency’s most frequent target has been fluoroquinolones.
It has warned that this class of antibiotics (including Cipro and Levaquin) increases the risk of tendinitis and tendon rupture, particularly in older adults; that it can cause the nerve damage called peripheral neuropathy; and that it can lead to hypoglycemia (low blood sugar).