Sunday, October 13, 2013

Serious peripheral neuropathy and fluoroquinolones

This week’s pharmacy pearl describes a recent alert from the FDA that you might have heard about regarding fluoroquinolones.  Fluoroquinolones are a diverse group of antibiotics used to treat various types of infections including pulmonary, genitourinary, skin, gastrointestinal, and bone infections. 

A recent warning from the FDA announced the potential for all systemic (IV or po) fluoroquinolones to cause serious peripheral neuropathy.  While peripheral neuropathy has been a known side effect of fluoroquinolones for nearly a decade, the FDA felt that the nature of this reaction was not sufficiently described.   They state that a large review has shown a continued association between fluoroquinolones and “disabling” peripheral neuropathy.  Peripheral neuropathy may occur rapidly, within a few days, and has persisted for longer than a year, even when the medication was discontinued.  No risk factors were identified, including age and duration of therapy.  The specific incidence or prevalence was not listed and it is likely underreported since the review was done through the FDA’s Adverse Events Reporting System.  Events occurred with all systemic drugs in this class.

The FDA advises that patients should be warned about the possibility of this side effect and to notify their provider in the event that it does occur.  Make sure patients know that signs of neuropathy include pain, burning, tingling, numbness, weakness, or changes in sensitivity in the arms or legs.  The medication should then be stopped and an alternative antibiotic continued unless the benefits outweigh the risks.

Fluoroquinolones as a class carry other serious warnings.  One of the boxed warnings on the labeling is the risk of tendon inflammation and/or rupture.  Risk factors for this include >60 years old, concurrent corticosteroids, and solid organ transplant recipients.  Another boxed warning is the use of fluoroquinolones in patients with myasthenia gravis as it can cause severe exacerbations of myasthenia gravis that require ventilator support.  The other warning and precautions for the class are QTc prolongation, CNS effects (including seizures and psychotic reactions), dysglycemias (either hypo- or hyperglycemia – higher risk in patients with diabetes – gatifloxacin was taken off the market for this reason in 2006), photosensitivity, and hypersensitivity reactions.

Take home points:

  • Fluoroquinolones can cause rapid-onset, prolonged or permanent, disabling peripheral neuropathy
  • Fluoroquinolones have a litany of adverse effects that make them less desirable choices when treating patient with numerous comorbidities.
  • Take extra care to avoid these adverse effects at each point of care including during initial selection of antibiotics, during de-escalation, and when switching from the IV to po route upon discharge.
FDA Drug Safety Communication. 8/15/2013

photo by Ethan Hein

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