What antibiotic is effective for treating both strep throat and a urinary tract infection (UTI)?

Antibiotic Selection for Concurrent Strep Throat and UTI

For a patient requiring treatment of both strep throat and a UTI simultaneously, amoxicillin 500 mg orally every 8 hours is the optimal single antibiotic choice, as it effectively treats both Group A streptococcal pharyngitis and most uncomplicated UTIs, particularly those caused by Enterococcus faecalis. 1, 2, 3

Rationale for Amoxicillin as Single-Agent Therapy

• Strep throat coverage: Penicillin and its congeners (including amoxicillin) remain the treatment of choice for Group A streptococcal pharyngitis due to proven efficacy, safety, narrow spectrum, and low cost 1

• UTI coverage: Amoxicillin is the drug of choice for enterococcal UTIs when susceptibility is confirmed, with high clinical (88.1%) and microbiological (86%) eradication rates 2, 3

• Practical advantage: Using a single antibiotic reduces pill burden, cost, drug interactions, and adverse effects compared to dual therapy 1, 2

Treatment Regimen

• Dosing: Amoxicillin 500 mg orally every 8 hours 2, 3

• Duration: 10 days to ensure adequate eradication of Group A streptococcus from the pharynx (the longer of the two required treatment durations) 1

• Alternative for penicillin allergy: Erythromycin for strep throat combined with nitrofurantoin 100 mg four times daily for 7 days for the UTI 1

Important Clinical Considerations

• Confirm diagnoses: Obtain throat culture or rapid antigen detection test (RADT) for strep throat; obtain urine culture for UTI to confirm bacterial etiology and susceptibility 1

• E. coli UTI caveat: If the UTI is caused by E. coli rather than Enterococcus, amoxicillin may not provide adequate coverage due to high resistance rates (84.9% for ampicillin in some cohorts) 1. In this scenario, consider:

  • Treating strep throat with amoxicillin 500 mg every 8 hours for 10 days 1
  • Adding nitrofurantoin 100 mg four times daily for 7 days OR fosfomycin 3g single dose for the UTI 1, 2

• Fluoroquinolone warning: Avoid levofloxacin despite its activity against both conditions 4. The FDA issued an advisory in 2016 warning against fluoroquinolones for uncomplicated UTIs due to unfavorable risk-benefit ratios, and they are not first-line for strep throat 1, 5

Common Pitfalls to Avoid

• Do not use fluoroquinolones empirically: Despite broad coverage, they carry significant adverse effects including disabling side effects, and resistance rates are increasing (47-46% for Enterococcus) 1, 3

• Do not treat asymptomatic bacteriuria: If the patient has positive urine culture without UTI symptoms, treating it increases risk of symptomatic infection and bacterial resistance 1

• Do not use shorter courses for strep throat: While 5-7 day courses may work for UTIs, Group A streptococcus requires the full 10-day course of oral antibiotics to achieve maximal pharyngeal eradication 1

• Verify compliance: If patient adherence is questionable, consider intramuscular benzathine penicillin G for strep throat (single dose) combined with oral therapy for UTI 1

Alternative Dual-Therapy Approach

If amoxicillin is contraindicated or the UTI pathogen is resistant:

• For strep throat: Erythromycin or first-generation cephalosporin (e.g., cephalexin) for 10 days 1
• For UTI: Nitrofurantoin 100 mg four times daily for 7 days OR fosfomycin 3g single dose 1, 2, 6