Health experts have been wondering about the increased prevalence of kidney stones (nephrolithiasis) in the general population in the last two to three decades.

Some report a 70 percent to almost double the prevalence of kidney stones, which may require surgery sometimes.

And this increased prevalence has been noted even in children!

Although many attribute it to the modern-day, high-protein, high-salt diet, a recently published study suggests that there might be a link between nephrolithiasis risk and five types of antibiotics commonly prescribed by doctors, or taken by some even without doctor’s advice.

The researchers reported the increased risk within a year after taking the antibiotics, and the risk of kidney stones persisted for years.

Individuals of all ages were at risk, but adolescents and children appeared to be at highest risk.

The antibiotics identified in the study were sulfas, cephalosporins, fluoroquinolones, nitrofurantoin and broad-spectrum penicillin.

The relatively highest risk was identified for the sulfa drugs.

The study was published online in the May issue of the Journal of the American Society of Nephrology.

According to Dr. Gregory Tasian, one of the authors of the study and an assistant professor of urology and epidemiology at the University of Pennsylvania Perelman School of Medicine, the increased risk appeared to persist for three to five years, and pediatric patients were the most vulnerable to developing the kidney stones.

He explained that these findings reinforce the findings in previous studies. The added knowledge was that prior studies “did not know which specific classes of antibiotics would be associated with an increased risk of stones and which ones would not.”

Symptoms

So parents of children who have taken the five antibiotics identified in this study should monitor in the next five years for signs and symptoms of kidney stones, which may include:

• Sharp pains in the back, side, lower abdomen or groin;

• Hematuria or unusual color of urine (pinkish, reddish or brownish);

• A constant urge to urinate;

• Dysuria or painful urination;

• Inability to urinate or urinating with small amount only, with the sensation that there’s more urine inside the bladder;

• Cloudy or bad-smelling urine;

• Generalized irritability or restlessness, especially in children.

The authors could not be certain as to why the five antibiotics seemed to promote the development of kidney stones. A hypothesis is that these antibiotics, particularly the sulfas, might induce changes in the microbiome (bacteria in the intestines and urinary tract), or in macronutrient metabolism.

Dr. Tasian clarified that this study should not prevent doctors from prescribing the antibiotics if they’re really strongly indicated to treat infections caused by susceptible bacteria.

C&S test

In some instances, doctors request first for a culture and sensitivity (C&S) test to make sure the culprit bacteria causing the infection is really susceptible to the antibiotic the doctor is going to prescribe.

But in some life-threatening cases, when one can no longer wait for the results of the C&S, the attending physician uses his or her best judgment which antibiotic to prescribe. If no satisfactory response is noted after 24 to 48 hours, the results of the C&S, which should already be available by this time, can guide a more appropriate use of antibiotic.

However, if the patient already shows remarkable clinical improvement—relief of fever and other signs and other symptoms of infection, the antibiotic, which was initially prescribed, is usually maintained regardless of the results of the C&S.

“Antibiotics have saved millions of lives and are needed to prevent death and serious harm from infections,” Dr. Tasian explained. “The benefits outweigh the potential harms.”

‘Appropriate use’

He emphasized, though, that doctors and patients must support “the judicious and appropriate use of antibiotics.”

Most hospitals now have antibiotic stewardship programs, usually managed by a committee of experts, to ensure that physicians are always conscious of the potential adverse effects of antibiotics and promote judicious antibiotic stewardship.

The findings in this study should discourage everyone from taking antibiotics inappropriately, even if they’re not indicated.

Many people self-medicate with antibiotics when they have fever, flu symptoms or sore throat. Most of these are caused by a viral infection, and antibiotics won’t really help. Self-medication and inappropriate intake of antibiotics would just promote resistance to antibiotics, and as shown in this study, also kidney stones.

With inappropriate use of antibiotics, the harm clearly outweighs the benefit. And it violates the cardinal rule in medicine, which is, “First, do no harm.”