What is the appropriate amoxicillin‑clavulanate (Augmentin) dosing for an adult with diverticulitis and impaired renal function?

Augmentin Renal Dosing for Diverticulitis

For adults with diverticulitis and impaired renal function requiring antibiotics, amoxicillin-clavulanate (Augmentin) dosing must be adjusted based on creatinine clearance (CrCl), with standard dosing only appropriate for CrCl >30 mL/min. 1, 2

When Antibiotics Are Actually Needed

Before discussing renal dosing, recognize that most immunocompetent patients with uncomplicated diverticulitis do NOT require antibiotics at all 1, 2. Reserve antibiotics for:

• Immunocompromised status (chemotherapy, organ transplant, high-dose steroids) 1, 2
• Age >80 years 1
• Significant comorbidities (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 1, 2
• Systemic inflammatory response or sepsis 1, 2
• CRP >140 mg/L or WBC >15 × 10⁹ cells/L 1, 2
• Fluid collection or longer segment of inflammation on CT 1, 2
• Persistent vomiting or inability to maintain hydration 1, 2

Renal Dosing Algorithm for Augmentin

CrCl >30 mL/min:

• Standard dosing: 875/125 mg orally twice daily for 4-7 days 1, 2, 3
• No adjustment needed 4, 5

CrCl 10-30 mL/min:

• Reduce to 500/125 mg orally twice daily OR 875/125 mg once daily 4, 5
• The differential clearance between amoxicillin and clavulanate becomes significant in this range, with amoxicillin accumulating more than clavulanate 5

CrCl <10 mL/min:

• 500/125 mg orally once daily 4, 5
• Consider alternative regimens if possible, as the amoxicillin-to-clavulanate ratio increases dramatically (14.7:1 vs. 4.9:1 in normal renal function) 5

Hemodialysis patients:

• 500/125 mg orally once daily, administered AFTER dialysis 4, 5
• Hemodialysis removes both amoxicillin (half-life 2.3 hours during dialysis) and clavulanate 4, 5
• Supplemental dose of 500/125 mg after each dialysis session 4, 5

Inpatient IV-to-Oral Transition Strategy

For hospitalized patients requiring initial IV therapy:

• Start with amoxicillin-clavulanate 1200 mg IV four times daily (if CrCl >30 mL/min) 1
• Transition to oral Augmentin as soon as patient tolerates oral intake (typically within 48 hours) 1, 6
• Hospital stays are actually shorter with early oral transition (2 vs. 3 days) 1, 6

Duration of Therapy

• Immunocompetent patients: 4-7 days total 1, 2
• Immunocompromised patients: 10-14 days 1, 2
• Post-drainage of abscess with adequate source control: 4 days 1, 7

Alternative Regimens for Renal Impairment

If Augmentin is problematic due to severe renal dysfunction:

• Ciprofloxacin 500 mg orally twice daily PLUS metronidazole 500 mg orally three times daily 1, 2
  • Ciprofloxacin requires dose reduction: 250-500 mg every 12-24 hours for CrCl <30 mL/min
  • Metronidazole requires no renal adjustment

Critical Pitfalls to Avoid

• Do NOT use standard dosing in patients with CrCl <30 mL/min – amoxicillin accumulation significantly exceeds clavulanate accumulation, creating an imbalanced ratio 5
• Do NOT prescribe antibiotics for uncomplicated diverticulitis in immunocompetent patients without risk factors – this provides no clinical benefit and contributes to resistance 1, 2
• Do NOT extend antibiotics beyond 7 days in immunocompetent patients – longer courses do not improve outcomes 1, 2
• Do NOT forget to adjust for actual body weight in obese patients – volume of distribution affects loading doses 8

Monitoring Parameters

• Renal function (serum creatinine, CrCl) at baseline and if clinical deterioration occurs 1, 2
• WBC and CRP to assess treatment response 7, 2
• Clinical re-evaluation within 7 days (or sooner if symptoms worsen) is mandatory 1, 2