June 14 (UPI) -- Researchers at Johns Hopkins Medicine found adverse side effects from prescribed antibiotics occurred in one-fifth of adult hospitalized patients.

The study consisted of 1,488 adults admitted to the general medicine services at The Johns Hopkins Hospital between September 2013 and June 2014 and received at least 24 hours of antibiotic treatment who were followed for 30 days after discharge to identify any adverse reactions to the antibiotics.


"Too often, clinicians prescribe antibiotics even if they have a low suspicion for a bacterial infection, thinking that even if antibiotics may not be necessary, they are probably not harmful," Dr. Pranita Tamma, an assistant professor of pediatrics and director of the Pediatric Antimicrobial Stewardship Program at The Johns Hopkins Hospital, said in a press release.

"But that is not always the case. Antibiotics have the potential to cause real harm to patients. Each time we think to prescribe an antibiotic, we need to pause and ask ourselves, Does this patient really need an antibiotic? If the patient develops an antibiotic-associated adverse reaction, even though that is, of course, unfortunate, we should be able to take some comfort in knowing that at least the antibiotic was truly necessary."

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The study, which was published June 12 in JAMA Internal Medicine, found 20 percent of patients who received antibiotics had one or more side effects and that each additional 10 days of antibiotics increased the risk of side effects by 3 percent.

Among the most common side effects, 42 percent of participants experienced gastrointestinal abnormalities, 24 percent experienced kidney abnormalities and 15 percent experienced blood abnormalities.

The participants were followed for up to 90 days for the development of Clostridium difficile infection and new multidrug-resistant infections. Researchers found 4 percent of patients developed C. difficile and 6 percent of patients developed multidrug-resistant organism infections.

The study found that 19 percent of antibiotics prescribed to patients were considered clinically unnecessary.

"In general, we would expect our hospital to have lower numbers of antibiotic-associated side effects than at hospitals without antibiotic stewardship programs because our stewardship team assists health care providers with optimizing the administration of antibiotics, and we tend to recommend targeted therapies for shorter periods of time," said Dr. Sara Cosgrove, a professor of medicine and director of the Antimicrobial Stewardship Program at The Johns Hopkins Hospital.