What is the recommended dose of Augmentin (amoxicillin-clavulanate) for a urinary tract infection (UTI) in an elderly female with impaired renal function?

Augmentin Dosing for UTI in Elderly Females

For uncomplicated UTI in elderly females, Augmentin 375 mg (250 mg amoxicillin/125 mg clavulanic acid) three times daily for 7-10 days is the recommended regimen, with mandatory dose adjustment if creatinine clearance is below 30 mL/min. 1, 2

Critical First Step: Assess Renal Function

• Calculate creatinine clearance before prescribing – this is non-negotiable in elderly patients as 29.5% have some degree of renal impairment that requires dose modification 1
• If CrCl <30 mL/min, reduce frequency or consider alternative antibiotics 3
• Failure to adjust for renal function is a common pitfall that increases toxicity risk 3

Standard Dosing Protocol

For Normal Renal Function (CrCl >30 mL/min):

• Augmentin 375 mg (250/125 mg) orally three times daily 1, 2
• Duration: 7-10 days for uncomplicated cystitis 4, 3
• This regimen achieved 76.9% cure rates in elderly patients with UTI 5

For Impaired Renal Function (CrCl <30 mL/min):

• Reduce dosing frequency or select an alternative antibiotic 3
• Consider fosfomycin 3g single dose as an alternative that doesn't require renal adjustment 3

Important Diagnostic Considerations Before Prescribing

Do NOT prescribe antibiotics if:

• Urinalysis shows negative nitrite AND negative leukocyte esterase 4, 6
• Patient has asymptomatic bacteriuria (common in up to 40% of institutionalized elderly women) 3

DO prescribe if patient has:

• Recent onset dysuria with frequency, urgency, or incontinence 4
• Costovertebral angle tenderness (suggests pyelonephritis – may need longer treatment) 4, 6
• Atypical presentations: new confusion, falls, functional decline, or fatigue 4, 3

Why Augmentin May Not Be First-Line

While Augmentin is effective, current European Urology guidelines recommend fosfomycin, nitrofurantoin (if CrCl >30 mL/min), or pivmecillinam as preferred first-line agents for uncomplicated UTI in elderly patients 4, 3. These alternatives have:

• Better resistance profiles 4
• Fewer drug interactions in polypharmacy patients 4
• Simpler dosing schedules (fosfomycin is single-dose) 3

However, Augmentin remains appropriate when:

• First-line agents are contraindicated 7
• Patient has recurrent UTIs with documented susceptibility 2
• Multiply-resistant organisms are suspected 7

Monitoring and Follow-Up

• Clinical response should occur within 48-72 hours 1
• If symptoms persist beyond 3 days, obtain urine culture and consider alternative diagnosis 4
• Watch for gastrointestinal side effects (20% incidence, though usually mild) 2
• Do not treat based solely on urine appearance changes (cloudy, odor) without infection criteria 4, 6

Common Pitfalls to Avoid

• Treating asymptomatic bacteriuria – extremely common mistake that drives resistance 6, 3
• Assuming typical UTI symptoms – elderly often present with confusion or falls instead of dysuria 4, 3
• Ignoring renal function – leads to drug accumulation and toxicity 3, 1
• Using fluoroquinolones as first-line – higher adverse effect risk in elderly (CNS effects, tendon rupture) 8, 6