How should Augmentin (amoxicillin‑clavulanate) be dosed for an otherwise healthy adult with a urinary‑tract infection, for children ≥2 months old, and for patients with impaired renal function (creatinine clearance <30 mL/min)?

Augmentin (Amoxicillin-Clavulanate) Dosing

For an otherwise healthy adult with a urinary tract infection, prescribe Augmentin 500 mg/125 mg (one tablet) orally three times daily for 7 days; for children ≥2 months old, use 20–40 mg/kg/day (amoxicillin component) divided into three doses; and for patients with creatinine clearance <30 mL/min, reduce the frequency to twice daily or once daily depending on severity of renal impairment.

Adult Dosing for Urinary Tract Infections

• Standard regimen: Augmentin 500 mg/125 mg (amoxicillin/clavulanate) orally three times daily for 7 days is the typical adult dose for uncomplicated UTI 1, 2.
• An alternative formulation is Augmentin 375 mg (250 mg amoxicillin + 125 mg clavulanate) three times daily, which has demonstrated a ~70% success rate even against amoxicillin-resistant organisms 2.
• Duration: A 7-day course is standard for UTI treatment with Augmentin 3, 4.
• The combination of amoxicillin and clavulanic acid is particularly valuable for multiply resistant bacteria commonly encountered in urinary tract infections 2, 4.

Pediatric Dosing (Children ≥2 Months Old)

• Weight-based dosing: Administer 20–40 mg/kg/day (based on the amoxicillin component) divided into three doses 1.
• For moderate infections, use the lower end of the range (20 mg/kg/day); for more severe infections, use up to 40 mg/kg/day 1.
• Augmentin has been shown to be effective and safe for bacterial infections of the urinary tract in children, with prompt clinical response 5.
• The oral suspension formulation is preferred for young children who cannot swallow tablets 5.

Renal Impairment Dosing (CrCl <30 mL/min)

• Moderate renal impairment (CrCl 10–30 mL/min): Reduce dosing frequency to 500 mg/125 mg twice daily 3.
• Severe renal impairment (CrCl <10 mL/min): Further reduce to 500 mg/125 mg once daily 3.
• In a study of 26 patients with chronic renal insufficiency (glomerular filtration 55–70 mL/min), Augmentin was well tolerated without dose adjustment, but closer monitoring is prudent 3.
• Do not use standard three-times-daily dosing in patients with significant renal dysfunction, as drug accumulation can occur 3.

Administration and Tolerability

• Augmentin is generally well tolerated, with minimal gastrointestinal side effects reported in most studies 2, 3, 4.
• Taking the medication with food may reduce gastrointestinal upset 2.
• Mild gastrointestinal complaints (nausea, diarrhea) occur in approximately 6–20% of patients but rarely require discontinuation 3, 4, 5.

Clinical Efficacy Considerations

• Microbiological cure rates of 67–84% have been documented in recurrent UTI patients treated with Augmentin 4.
• The addition of clavulanic acid overcomes β-lactamase-mediated resistance, making Augmentin effective against many organisms resistant to amoxicillin alone 2, 4.
• For recurrent UTIs, Augmentin may be considered a first-line agent given increasing resistance to other commonly used outpatient antibiotics 4.

Common Pitfalls to Avoid

• Do not underdose in children: Always calculate the mg/kg dose based on current weight, not outdated measurements 1, 5.
• Do not forget renal adjustment: Failure to reduce dosing frequency in renal impairment can lead to drug accumulation and increased toxicity 3.
• Do not use single-dose therapy for complicated UTI: While single-dose amoxicillin has been studied for uncomplicated UTI, Augmentin for UTI requires a full 7-day course 6, 4.
• Do not assume all UTI pathogens are susceptible: Local resistance patterns should guide empiric therapy, and culture results should prompt adjustment if needed 2, 4.