How to manage a 49-year-old female (YOF) with an umbilical infection due to Actinomyces/Enterococcus, currently on levofloxacin (ofloxacin) and doxycycline (vibramycin) for 9 or 28 days, presenting with myalgia and arthralgia, negative C-reactive protein (CRP) and no leukocytosis?

Management of Fluoroquinolone-Associated Myalgia and Arthralgia

Discontinuation of levofloxacin is strongly recommended for this patient experiencing myalgia and arthralgia after 9 days of therapy, as these are recognized adverse effects of fluoroquinolones that may progress to more serious tendon complications if the medication is continued.

Clinical Assessment

• Myalgia and arthralgia are common adverse effects of fluoroquinolones like levofloxacin, occurring in approximately 25% of patients - more than twice the incidence of any other adverse effect 1
• These symptoms typically begin after an average of 3 days of therapy and may resolve approximately 7.5 days after discontinuation of the medication 1
• The negative CRP and absence of leukocytosis support that these symptoms are medication-related rather than due to worsening infection 2
• Fluoroquinolone-associated arthralgia is thought to occur in approximately 1% of patients according to general data, but specific studies in sinusitis patients found much higher rates (25%) 2

Immediate Management

• Discontinue levofloxacin immediately to prevent progression to more serious tendon complications 2, 3
• Consider switching to an alternative antibiotic regimen based on culture results:
  • For Actinomyces: Amoxicillin, penicillin, or clindamycin 2
  • For Enterococcus: Ampicillin, amoxicillin, or vancomycin (if penicillin-allergic) 2

Supportive Care

• Recommend rest and avoidance of strenuous physical activity until symptoms resolve 2
• Consider magnesium and vitamin E supplementation, which has shown benefit in animal models of fluoroquinolone-induced cartilage damage 2
• Symptomatic pain management with acetaminophen (avoid NSAIDs if possible as they may increase risk of CNS effects with fluoroquinolones) 3
• Monitor for signs of tendon rupture such as:
  • Sudden pain or popping sensation in a tendon area
  • Bruising after an injury in a tendon area
  • Inability to move the affected area or bear weight 3

Follow-up Recommendations

• Arrange follow-up within 1 week to:
  • Assess resolution of myalgia and arthralgia symptoms
  • Evaluate response to alternative antibiotic therapy
  • Monitor for any signs of tendon complications 2
• Document fluoroquinolone reaction in the patient's medical record to avoid future exposure 3

Important Considerations

• Fluoroquinolones can inhibit osteoblastic cell growth and mineralization, potentially affecting bone healing 2
• Risk factors for fluoroquinolone-associated tendinopathy include:
  • Age over 60 years
  • Concomitant corticosteroid use
  • Kidney, heart, or lung transplant 3
• While this patient doesn't have these specific risk factors, the presence of symptoms indicates medication toxicity requiring intervention 2

Alternative Antibiotic Options

• Based on culture results showing Actinomyces/Enterococcus:
  • Amoxicillin-clavulanate: 875/125 mg twice daily 2
  • Clindamycin: 300-450 mg three times daily (if penicillin-allergic) 2
  • Complete a total of 14 days of effective antibiotic therapy for the umbilical infection 2

Prognosis

• Most fluoroquinolone-associated musculoskeletal symptoms resolve within 2 months after discontinuation 3
• Approximately 14% of patients experiencing these symptoms are unable to complete their course of therapy due to arthralgia and myalgia 1
• The patient should be informed that symptoms typically improve after discontinuation but may take several days to weeks to completely resolve 1, 4