The Food and Drug Administration is requiring a stronger warning about the potential for peripheral neuropathy with fluoroquinolone antibiotics that are taken orally or by injection.
The warning does not apply to topical formulations, which have not been associated with neuropathy. Drug labels and patient medication guides must be updated, said the agency.
The potential for neuropathy was first added to the labels of all drugs in the class in 2004. The new warning was necessary because "the potential rapid onset and risk of permanence were not adequately described" in the 2004 label iteration, the FDA noted.
Before requiring new warnings, the FDA reviewed its Adverse Event Reporting System (FAERS, formerly known as AERS) database. The agency found that cases of fluoroquinolone-associated peripheral neuropathy with an outcome of "disability" had been reported to the AERS database between January 2003 and August 2012, although the FDA did not say how many cases it found. The reports indicated a rapid onset of peripheral neuropathy, often within a few days of starting the quinolone. Some cases reported neuropathy that continued for a year, even though the medication had been stopped.
The database was not able to show whether neuropathy was permanent, however, because it is designed to collect spontaneous reports.
The FDA said it had not been able to identify any risk factors for the development of peripheral neuropathy. But the onset of the condition seemed to have no correlation with the patient’s age or how long they took the antibiotic.
The updated warnings apply to all approved fluoroquinolones: levofloxacin (Levaquin), ciprofloxacin (Cipro), moxifloxacin (Avelox), norfloxacin (Noroxin), ofloxacin (Floxin), and gemifloxacin (Factive).
According to the FDA, 23 million outpatients were prescribed an oral quinolone in 2011. A total of 70% received ciprofloxacin; 28% were prescribed levofloxacin; and 9% were given moxifloxacin. Gemifloxacin, ofloxacin, and norfloxacin each accounted for less than 1% of those patients in 2011.
There were 3.8 million inpatients who received an injectable quinolone in 2011. The most-prescribed was levofloxacin, accounting for 63% of prescriptions, followed by ciprofloxacin (28%) and moxifloxacin (13%).
The agency recommended that patients who develop neuropathy symptoms stop taking the quinolone and be treated with a different antibiotic, unless the benefit outweighs the risk. Patients taking the medications who develop symptoms are urged to tell their physician immediately.
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