Do I need to adjust the renal dose of amoxicillin‑clavulanate (Augmentin) for acute bacterial sinusitis in an adult with an estimated glomerular filtration rate of 44 mL/min?

Renal Dose Adjustment for Augmentin in Sinusitis with GFR 44

Yes, you need to adjust the dose of amoxicillin-clavulanate (Augmentin) for acute bacterial sinusitis when the GFR is 44 mL/min, but the standard 875/125 mg formulation can still be used with modified frequency.

Renal Dosing Recommendations

For GFR 30–50 mL/min (which includes your patient with GFR 44):

• No dose adjustment is required for the standard 875 mg/125 mg formulation—continue twice daily dosing as normal. 1
• The FDA label explicitly states that "patients with impaired renal function do not generally require a reduction in dose unless the impairment is severe" (defined as GFR <30 mL/min). 1

For GFR 10–30 mL/min:

• Reduce frequency to 500 mg/125 mg or 250 mg/125 mg every 12 hours (depending on infection severity). 1

For GFR <10 mL/min:

• Further reduce to 500 mg/125 mg or 250 mg/125 mg every 24 hours. 1
• Hemodialysis patients require an additional dose both during and at the end of dialysis. 1

Standard Sinusitis Dosing at GFR 44

Your patient can receive the full standard regimen:

• Amoxicillin-clavulanate 875 mg/125 mg orally twice daily for 5–10 days (or until symptom-free for 7 consecutive days, typically 10–14 days total). 2, 3, 4
• This provides 90–92% predicted clinical efficacy against the three major sinusitis pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis). 2, 3

High-Dose Regimen Considerations

If high-dose therapy is indicated (recent antibiotic use, age >65, daycare exposure, moderate-to-severe symptoms, comorbidities, immunocompromised state):

• The 2 g/125 mg twice daily regimen is also safe at GFR 44 mL/min, as the FDA cutoff for dose reduction is GFR <30 mL/min. 1
• However, avoid the 875 mg/125 mg dose in patients with GFR <30 mL/min per FDA labeling. 1

Monitoring and Reassessment

• Reassess at 3–5 days: If no improvement (persistent purulent drainage, unchanged facial pain, or worsening), switch to a respiratory fluoroquinolone (levofloxacin 500 mg daily or moxifloxacin 400 mg daily). 2, 3, 4
• Reassess at 7 days: Persistent or worsening symptoms warrant diagnostic reconsideration, exclusion of complications, and possible ENT referral. 2, 3

Essential Adjunctive Therapies

• Intranasal corticosteroids (mometasone, fluticasone, or budesonide) twice daily significantly reduce mucosal inflammation and accelerate symptom resolution—supported by strong evidence from multiple RCTs. 2, 3, 4
• Saline nasal irrigation 2–3 times daily provides symptomatic relief and aids mucus clearance. 2, 3
• Analgesics (acetaminophen or ibuprofen) for pain and fever control. 2, 3

Common Pitfall to Avoid

• Do not unnecessarily reduce the dose when GFR is 30–50 mL/min; the FDA explicitly permits standard dosing in this range, and underdosing may lead to treatment failure. 1
• Gastrointestinal adverse effects (diarrhea in 40–43% of patients; severe diarrhea in 7–8%) are common with amoxicillin-clavulanate but are not increased by renal impairment at this GFR level. 2, 4