New labeling requirements from the U.S. Food and Drug Administration will require stronger warnings about fluoroquinolone antibiotics side effects.

The FDA announced formal approval of the new labeling in July 2016. The new labeling enhances the warning about those side effects and discourages the use of fluoroquinolones in patients with less serious infections.

The agency now says that the risk of fluoroquinolone antibiotics side effects outweighs the benefits for patients with acute sinusitis, acute bronchitis, and uncomplicated urinary tract infections.

The new labeling recommends physicians avoid using fluoroquinolones in these patients unless they have no other treatment options.

The changes will add an updated “boxed warning” and revisions to the label’s Warnings and Precautions section alerting patients and doctors to the risk of disabling and potentially irreversible fluoroquinolone antibiotics side effects, which can occur together.

The label will also include limitation-of-use guidelines for physicians. The patient Medication Guide included with the drugs’ packaging will also be updated.

The label change was originally announced earlier in a May 2016 advisory. Based on recent research, the FDA says that fluoroquinolones in tablet, capsule and injectable form “are associated with disabling and potentially permanent serious side effects that can occur together.”

Research revealed side effects that involve the joints, muscles, tendons, nerves, and central nervous system. These side effects may set in hours to weeks after exposure to fluoroquinolones, the agency says, and they have the potential to be permanent.

In November 2015, an FDA advisory committee reviewed research about these side effects, paying particular attention to the risk of two or more side effects occurring at the same time, creating a risk of permanent impairment. The committee concluded that for certain less severe infections, the risk of fluoroquinolone antibiotic side effects outweighed the clinical benefits.

Fluoroquinolones are a class of antibiotics that prevent the growth of bacteria. These drugs include Avelox (known generically as moxifloxacin), Cipro (ciprofloxacin), Factive (gemifloxacin), Levaquin (levofloxacin), and Ocuflox (ofloxacin).

Prior Warnings About Fluoroquinolone Antibiotics Side Effects

A prior boxed warning issued in 2008 added an alert about the risk of tendinitis and tendon rupture associated with fluoroquinolones. Later updates added warnings about the risk of aggravating symptoms of myasthenia gravis in 2011 and about the possibility of irreversible peripheral neuropathy in 2013.

Serious symptoms of the side effects in question include confusion, hallucinations, a pins-and-needles or pricking sensation, and pain in the muscles, tendons or joints.

The FDA recommends patients taking fluoroquinolones seek medical attention immediately if they experience any of these serious symptoms.

In addition to the side effects addressed by the FDA, other studies have shown an increased incidence of aortic injuries, such as aortic dissection and aortic aneurysm, both of which can put the patient in an immediate risk of death.

Side effects of fluoroquinolones have been at the center of some recent products liability litigation. A Pennsylvania judge denied a proposal to consolidate dozens of claims already filed over the risk of peripheral neuropathy associated with fluoroquinolones.

Generally, plaintiffs in these claims argue that manufacturers of fluoroquinolones failed to provide them with an adequate warning about fluoroquinolone antibiotics side effects, preventing them from making an informed decision about their medications.