What oral antibiotic can I prescribe for acute bacterial sinusitis in a patient with penicillin allergy who is experiencing doxycycline‑induced nausea/vomiting and cannot use codeine?

Recommended Antibiotic for Acute Bacterial Sinusitis with Doxycycline Intolerance and Penicillin Allergy

Switch immediately to levofloxacin 500 mg once daily for 10–14 days (or moxifloxacin 400 mg once daily for 10 days), which provides 90–92% predicted clinical efficacy against all major sinusitis pathogens and is the guideline-recommended first-line choice for patients with penicillin allergy who cannot tolerate doxycycline. 1

Why Levofloxacin/Moxifloxacin Is the Correct Choice

• For patients with documented penicillin allergy experiencing doxycycline-induced nausea/vomiting, respiratory fluoroquinolones (levofloxacin or moxifloxacin) are the preferred antibiotics because they provide excellent coverage against Streptococcus pneumoniae (including multidrug-resistant strains), β-lactamase-producing Haemophilus influenzae, and Moraxella catarrhalis. 1, 2

• Levofloxacin 500 mg once daily for 10–14 days achieves 90–92% predicted clinical efficacy and is specifically recommended for penicillin-allergic patients with acute bacterial sinusitis. 1, 3

• Moxifloxacin 400 mg once daily for 10 days offers equivalent efficacy (90–92%) and may improve compliance with once-daily dosing. 1

Why NOT Other Options

Cephalosporins (Cefuroxime, Cefpodoxime, Cefdinir)

• Second- or third-generation cephalosporins are appropriate ONLY for non-severe (non-Type I) penicillin allergy (e.g., mild rash without anaphylaxis). 1, 3

• If the patient has a severe/anaphylactic penicillin allergy, cephalosporins carry a 1–10% cross-reactivity risk and should be avoided. 2

• You must first clarify the type of penicillin allergy: if the patient had anaphylaxis, urticaria, or angioedema with penicillin, use fluoroquinolones; if the allergy was a mild rash, cephalosporins are safe. 1

Azithromycin and Other Macrolides

• Azithromycin is explicitly contraindicated for acute bacterial sinusitis due to resistance rates exceeding 20–25% for both S. pneumoniae and H. influenzae. 1, 2

• The American Academy of Pediatrics states azithromycin should NOT be used to treat acute bacterial sinusitis in persons with penicillin hypersensitivity due to resistance patterns. 1

Trimethoprim-Sulfamethoxazole (Bactrim)

• Bactrim should not be used because resistance is approximately 50% in S. pneumoniae and 27% in H. influenzae. 1, 2

Diagnostic Confirmation Before Prescribing

• Antibiotics are indicated only when acute bacterial sinusitis is confirmed by at least ONE of the following patterns: 1

  • Persistent symptoms ≥10 days without improvement (purulent nasal discharge plus obstruction or facial pain/pressure)
  • Severe symptoms ≥3–4 consecutive days with fever ≥39°C, purulent discharge, and facial pain
  • "Double sickening" – initial improvement from a viral URI followed by worsening within 10 days

• Approximately 98–99.5% of acute rhinosinusitis cases are viral and resolve spontaneously within 7–10 days; do NOT prescribe antibiotics for symptoms <10 days unless severe features are present. 1

Managing Nausea/Vomiting

• Discontinue doxycycline immediately – the patient's nausea/vomiting is likely drug-induced (doxycycline causes GI adverse effects in a significant proportion of patients). 1

• Prescribe antiemetics as needed (ondansetron 4–8 mg orally every 8 hours as needed, or promethazine 12.5–25 mg orally/rectally every 4–6 hours as needed) to control nausea while initiating levofloxacin. 1

• Ensure adequate hydration – patients with nausea/vomiting may be dehydrated, which can worsen sinusitis symptoms. 1

Essential Adjunctive Therapies (Add to ALL Patients)

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily significantly reduce mucosal inflammation and accelerate symptom resolution; this recommendation is supported by strong evidence from multiple randomized controlled trials. 1

• Saline nasal irrigation 2–3 times daily provides symptomatic relief and aids mucus clearance. 1

• Analgesics (acetaminophen or ibuprofen) for pain and fever control. 1

Treatment Duration and Monitoring

• Continue levofloxacin for 10–14 days or until the patient is symptom-free for 7 consecutive days (typically 10–14 days total). 1

• Reassess at 3–5 days: if no clinical improvement (persistent purulent drainage, unchanged facial pain, or worsening), consider switching antibiotics or re-evaluating the diagnosis. 1

• Reassess at 7 days: persistent or worsening symptoms warrant confirmation of diagnosis, exclusion of complications (orbital cellulitis, meningitis), and possible imaging or ENT referral. 1

Expected Timeline of Recovery

• Noticeable improvement should occur within 3–5 days of appropriate antibiotic therapy. 1

• Complete resolution typically occurs by 10–14 days or when the patient is symptom-free for 7 consecutive days. 1

Red-Flag Situations Requiring Urgent ENT Referral

• No improvement after 7 days of appropriate levofloxacin therapy 1

• Worsening symptoms at any point (increasing facial pain, fever, purulent drainage) 1

• Signs of complications: severe headache, visual changes, periorbital swelling/erythema, proptosis, diplopia, altered mental status, or cranial nerve deficits 1

• Recurrent sinusitis (≥3 episodes per year) suggesting underlying allergic rhinitis, immunodeficiency, or anatomic abnormalities 1

Critical Pitfalls to Avoid

• Do NOT use doxycycline when the patient is experiencing nausea/vomiting – this is a clear indication to switch antibiotics. 1

• Do NOT prescribe azithromycin – resistance rates make treatment failure likely. 1, 2

• Fluoroquinolones should be reserved for penicillin-allergic patients or treatment failures to limit resistance development; however, in this case, the patient meets criteria for fluoroquinolone use (penicillin allergy + doxycycline intolerance). 1

• Ensure adequate treatment duration (minimum 10 days) to prevent relapse. 1