What is the typical dose of amoxicillin (Amoxicillin)/clavulanic acid (Clavulanic acid) for treating Urinary Tract Infections (UTIs)?

Amoxicillin/Clavulanic Acid Dosing for UTIs

For adults with uncomplicated UTIs, use amoxicillin/clavulanate 500 mg/125 mg every 12 hours or 250 mg/125 mg every 8 hours for 5-7 days, with the every-12-hour regimen preferred due to significantly less diarrhea. 1

Adult Dosing

Standard dosing:

• 500 mg/125 mg every 12 hours (preferred regimen - associated with significantly less diarrhea) 1
• Alternative: 250 mg/125 mg every 8 hours 1

For more severe infections or respiratory involvement:

• 875 mg/125 mg every 12 hours, OR 1
• 500 mg/125 mg every 8 hours 1

Treatment duration:

• Complicated UTIs: 5-10 days 2
• Uncomplicated UTIs: 5-7 days 3

Pediatric Dosing

For children ≥12 weeks (3 months) and older:

• Less severe infections: 25 mg/kg/day divided every 12 hours OR 20 mg/kg/day divided every 8 hours 1
• More severe infections: 45 mg/kg/day divided every 12 hours OR 40 mg/kg/day divided every 8 hours 1
• The American Academy of Pediatrics recommends 20-40 mg/kg/day divided into 3 doses 2

For neonates and infants <12 weeks:

• 30 mg/kg/day divided every 12 hours (based on amoxicillin component) 1
• Use 125 mg/31.25 mg per 5 mL oral suspension formulation 1

Children weighing ≥40 kg: Follow adult dosing recommendations 1

Critical Considerations for Empiric Therapy

Resistance patterns matter significantly:

• The IDSA and European Society for Microbiology and Infectious Diseases recommend against using amoxicillin alone for empirical UTI treatment due to very high resistance rates (approximately 75% of E. coli isolates globally) 4
• However, amoxicillin/clavulanate remains a viable option when local susceptibility patterns support its use 2, 4
• Local antimicrobial resistance patterns should guide empiric therapy selection 2

When to avoid amoxicillin/clavulanate:

• Not recommended for asymptomatic bacteriuria 2
• Should not be used for initial empirical treatment of severe pyelonephritis or complicated UTIs in hospitalized patients due to inadequate antimicrobial coverage 5
• Susceptibility testing should be performed when possible to adjust therapy 2

Special Clinical Scenarios

For multidrug-resistant organisms:

• Alternative agents may be required for UTIs caused by carbapenem-resistant organisms 3, 2
• Aminoglycosides (gentamicin 5-7 mg/kg/day IV once daily or amikacin 15 mg/kg/day IV once daily) are options for complicated UTIs due to resistant organisms 3

High-dose regimens for resistant organisms:

• Recent evidence suggests high-dose amoxicillin/clavulanate (2875 mg amoxicillin/125 mg clavulanic acid twice daily, down-titrated over time) may overcome ESBL-producing K. pneumoniae in select outpatient cases 6
• This approach achieved no therapeutic failures in a small observational study of recurrent UTIs 6

Administration Pearls

• Can be given without regard to meals, though clavulanate absorption is enhanced when taken with food 1
• The 875 mg/125 mg formulation is associated with significantly fewer severe diarrhea episodes compared to 500 mg/125 mg every 8 hours 1
• Adults with difficulty swallowing may use suspension formulations as alternatives to tablets 1
• Monitor hepatic function in hepatically impaired patients 1