Augmentin Dosing for UTI in Elderly Patients
For elderly patients with UTI and normal renal function, prescribe Augmentin 500 mg/125 mg every 12 hours for 7-10 days; if creatinine clearance is 10-30 mL/min, reduce to 500 mg/125 mg every 12 hours, and if creatinine clearance is <10 mL/min, reduce to 500 mg/125 mg every 24 hours. 1
Dosing Based on Renal Function
The FDA label provides explicit dosing adjustments for renal impairment, which is critical in elderly patients 1:
- Normal renal function (CrCl >30 mL/min): 500 mg/125 mg every 12 hours or 875 mg/125 mg every 12 hours for more severe infections 1
- CrCl 10-30 mL/min: 500 mg/125 mg or 250 mg/125 mg every 12 hours depending on infection severity 1
- CrCl <10 mL/min: 500 mg/125 mg or 250 mg/125 mg every 24 hours depending on infection severity 1
- Hemodialysis patients: 500 mg/125 mg or 250 mg/125 mg every 24 hours, with an additional dose during and at the end of dialysis 1
Critical caveat: The 875 mg/125 mg dose should NOT be used in patients with CrCl <30 mL/min 1. This is a common prescribing error to avoid in elderly patients who frequently have reduced renal function.
Treatment Duration
Treat for 7-10 days rather than shorter courses in elderly patients. 2, 3 While research shows that 3-6 day courses may be sufficient for uncomplicated UTIs in elderly women 3, the European Urology guidelines recommend 7-10 days for this population 2. The Cochrane review found no significant difference between short-course (3-6 days) and long-course (7-14 days) treatment at long-term follow-up 3, but given the higher complication rates in elderly patients, the longer duration is prudent.
Efficacy in Elderly Patients
Augmentin demonstrates superior efficacy compared to amoxicillin alone in elderly UTI patients, with an 87.5% response rate versus 43% for amoxicillin in patients with mean age 82 years 4. This is particularly relevant because elderly patients often harbor amoxicillin-resistant organisms that remain susceptible to the amoxicillin-clavulanate combination 5.
Essential Pre-Treatment Assessment
Calculate creatinine clearance before prescribing - do not rely on serum creatinine alone in elderly patients, as muscle mass decline can mask significant renal impairment 1. Use the Cockcroft-Gault equation or measure actual creatinine clearance.
Confirm true UTI diagnosis before treating 6, 7:
- Require recent onset of dysuria, frequency, urgency, or costovertebral angle tenderness 6
- Do NOT treat asymptomatic bacteriuria, which occurs in up to 40% of institutionalized elderly women 7, 2
- Negative nitrites AND negative leukocyte esterase effectively rule out UTI 7
Common Pitfalls to Avoid
- Using 875 mg/125 mg dose in patients with CrCl <30 mL/min - this is explicitly contraindicated 1
- Treating asymptomatic bacteriuria - extremely common in elderly patients but does not require antibiotics 6, 7, 2
- Failing to adjust for renal function - elderly patients often have significant renal impairment despite normal serum creatinine 1
- Substituting two 250 mg/125 mg tablets for one 500 mg/125 mg tablet - these are NOT equivalent due to different clavulanate content 1