Amoxicillin-Clavulanate Oral Dosing for UTI

For adults with uncomplicated UTI (cystitis), use amoxicillin-clavulanate 875 mg/125 mg orally every 12 hours for 5-7 days. 1

Adult Dosing by UTI Type

875 mg/125 mg orally every 12 hours for 5-7 days 1
This dosing is supported by FDA clinical trial data showing comparable efficacy between the 875/125 mg twice daily and 500/125 mg three times daily regimens, with significantly lower rates of severe diarrhea (1% vs 2%) 2
E. coli demonstrates high susceptibility to this combination, unlike plain amoxicillin which has 75% median resistance 1

875 mg/125 mg orally every 12 hours for 7-14 days 1
Treatment duration of 7 days is appropriate when the patient has been afebrile for at least 48 hours and is hemodynamically stable 3
For men, use 14 days when prostatitis cannot be excluded 3
FDA trials in complicated UTI and pyelonephritis demonstrated bacteriologic cure rates of 81% at 2-4 days post-therapy and 52% at 2-4 weeks post-therapy with the 875/125 mg twice daily regimen 2

875 mg/125 mg orally every 12 hours for 7-14 days 1
A 3-day regimen may be considered only for younger women with mild CA-UTI after catheter removal 1
Remove the catheter as soon as clinically appropriate 1

20-40 mg/kg/day (based on amoxicillin component) divided into 3 doses for 7-14 days 3, 1
This is for febrile UTI in infants and young children 3
Total course should be 7-14 days; courses shorter than 7 days are inferior 3

Do not use for febrile UTI in infants if compliance is uncertain - consider parenteral therapy instead 3
Do not use if local E. coli resistance exceeds 20% - consider alternative agents 1
Do not use for asymptomatic bacteriuria - treatment may be harmful 3, 1
Avoid in patients who have used fluoroquinolones in the last 6 months if considering empiric therapy for complicated UTI 3

If no clinical response with defervescence by 72 hours, consider treatment extension and urologic evaluation 1
For ESBL-producing organisms, standard doses are typically inadequate; high-dose regimens (2875 mg amoxicillin twice daily with 125 mg clavulanate) have shown success in select cases, though this is not standard practice 4
For multidrug-resistant organisms (ESBL, carbapenem-resistant), alternative agents such as aminoglycosides or carbapenems are required 1

Always obtain urine culture and susceptibility testing before initiating therapy for complicated UTI 3
Tailor therapy based on culture results 3, 1
Local antimicrobial resistance patterns must guide empiric therapy selection 1

Do not confuse the 875/125 mg twice daily regimen with the older 500/125 mg three times daily regimen - the twice daily dosing has superior tolerability with equivalent efficacy 2
Do not use agents excreted only in urine (like nitrofurantoin) for febrile UTI - inadequate serum concentrations may fail to treat pyelonephritis or urosepsis 3
Do not empirically use amoxicillin-clavulanate in urology department patients - resistance rates are typically higher 3
The most common adverse effect is diarrhea (14-15%), with severe diarrhea occurring in approximately 1% of patients on the 875/125 mg twice daily regimen 2