What medication is recommended for an adult with a urinary tract infection (UTI) and a sinus infection?

Treatment for Adult with UTI and Sinus Infection

For an adult with both a urinary tract infection and sinus infection, treat each infection separately with appropriate antibiotics: amoxicillin-clavulanate 875/125 mg twice daily works for both conditions and can be used as a single agent if both infections are confirmed bacterial.

Confirming Bacterial Infections Before Treatment

Urinary Tract Infection Diagnosis

• Confirm UTI with urinalysis showing pyuria and positive urine culture 1
• Amoxicillin-clavulanate achieves 84% microbiological cure rates at 1 week and 67% at 1 month for recurrent UTIs 2
• Consider local resistance patterns, as high rates of trimethoprim-sulfamethoxazole and fluoroquinolone resistance may preclude their use 1

Acute Bacterial Sinusitis Diagnosis

• Only prescribe antibiotics if the patient meets one of three criteria: persistent symptoms ≥10 days without improvement, severe symptoms (fever >39°C with purulent discharge) for ≥3 consecutive days, or "double sickening" (worsening after initial improvement) 3, 4
• 98-99.5% of acute rhinosinusitis is viral and resolves spontaneously within 7-10 days without antibiotics 3
• Do not prescribe antibiotics for sinusitis symptoms lasting <10 days unless severe features are present 3

First-Line Antibiotic Treatment

Single Agent for Both Infections

Amoxicillin-clavulanate 875 mg/125 mg twice daily for 5-10 days treats both UTI and acute bacterial sinusitis effectively 4, 2, 5, 6

• For UTI: This regimen achieves 70% success rate for amoxicillin-resistant organisms and 84% microbiological cure at 1 week 2, 5
• For sinusitis: Provides 90-92% predicted clinical efficacy against major pathogens including drug-resistant S. pneumoniae and β-lactamase-producing H. influenzae 4
• The combination is particularly valuable for multiply resistant bacteria in both urinary and respiratory pathogens 5, 6

Treatment Duration

• UTI: 7 days is standard for uncomplicated infections 2
• Sinusitis: 5-10 days, with most guidelines recommending treatment until symptom-free for 7 days 4
• Use the longer duration (10 days total) to adequately treat both infections 4, 2

Alternative Options for Penicillin Allergy

Non-Severe Penicillin Allergy

• Second-generation cephalosporins: Cefuroxime for both infections 4
• Third-generation cephalosporins: Cefpodoxime or cefdinir for sinusitis, plus separate agent for UTI 4
• Risk of cross-reactivity with cephalosporins in penicillin-allergic patients is negligible 4

Severe Penicillin Allergy (Type I/Anaphylaxis)

• For sinusitis: Levofloxacin 500 mg once daily for 10 days (90-92% efficacy) 4
• For UTI: Fluoroquinolones, nitrofurantoin, or fosfomycin depending on local resistance patterns 1
• Reserve fluoroquinolones for documented severe allergies to prevent resistance development 4

Monitoring and Reassessment

Critical Timepoints

• 3-5 days: Reassess both infections; switch antibiotics if no improvement 4
• 7 days: Definitive assessment point; reconfirm diagnoses if symptoms persist 4
• For UTI: Expect reduction in dysuria and frequency by 3-5 days 2
• For sinusitis: Expect reduction in fever, facial pain, and purulent discharge by 3-5 days 4

Treatment Failure Protocol

If no improvement after 3-5 days:

• For sinusitis: Switch to high-dose amoxicillin-clavulanate (2 g/125 mg twice daily) or respiratory fluoroquinolone 4
• For UTI: Obtain repeat culture and adjust based on susceptibility results 1

Essential Adjunctive Therapies

For Sinusitis

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide twice daily) reduce mucosal inflammation and improve symptom resolution 4
• Saline nasal irrigation provides symptomatic relief 4
• Analgesics (acetaminophen or ibuprofen) for pain and fever 4

For UTI

• Adequate hydration to flush urinary tract 2
• Analgesics for dysuria if needed 1

Critical Pitfalls to Avoid

Antibiotic Selection Errors

• Never use azithromycin for sinusitis due to 20-25% resistance rates for both S. pneumoniae and H. influenzae 4
• Avoid trimethoprim-sulfamethoxazole if local resistance rates are high (50% for S. pneumoniae, 27% for H. influenzae) 4, 1
• Do not use first-generation cephalosporins (cephalexin) for sinusitis due to inadequate coverage against H. influenzae 4

Diagnostic Errors

• Do not prescribe antibiotics for viral rhinosinusitis (symptoms <10 days without severe features) 3
• Waiting beyond 7 days to change therapy in non-responders delays effective treatment 4

Dosing Errors

• Ensure adequate amoxicillin-clavulanate dosing: 875/125 mg twice daily, not lower doses 4, 2
• Complete full course even after symptoms improve to prevent relapse 4

Special Considerations

High-Risk Patients Requiring Higher Doses

Use high-dose amoxicillin-clavulanate (2 g/125 mg twice daily) for patients with:

• Recent antibiotic use within past month 4
• Age >65 years 4
• Moderate-to-severe symptoms 4
• Comorbid conditions or immunocompromised state 4

ESBL-Producing Organisms

• If UTI is caused by ESBL-producing E. coli or K. pneumoniae, high-dose amoxicillin-clavulanate (2875 mg amoxicillin/125 mg clavulanate twice daily) can break resistance in select cases 7
• Alternative oral options include nitrofurantoin, fosfomycin, or pivmecillinam 1, 6

When to Refer

• No improvement after 7 days of appropriate second-line therapy 4
• Worsening symptoms at any time 4
• Suspected complications (orbital cellulitis, meningitis for sinusitis; pyelonephritis for UTI) 4, 1
• Recurrent infections requiring evaluation for underlying causes 4