What is the recommended dosing for Augmentin (amoxicillin/clavulanate) in an elderly patient with impaired renal function?

Augmentin Dosing for Elderly Patients with Impaired Renal Function

For elderly patients with impaired renal function, standard Augmentin dosing should be used with careful monitoring, as no specific dose adjustment is recommended in the FDA labeling based on age or renal function alone, though hepatically impaired patients require caution and regular monitoring. 1

Standard Adult Dosing

The usual adult dose is one of the following 1:

• 500 mg/125 mg tablet every 12 hours, OR
• 250 mg/125 mg tablet every 8 hours

For more severe infections and respiratory tract infections 1:

• 875 mg/125 mg tablet every 12 hours, OR
• 500 mg/125 mg tablet every 8 hours

The 875 mg/125 mg every 12 hours regimen is associated with significantly less severe diarrhea compared to 500 mg/125 mg every 8 hours in adults. 1

Critical Considerations for Elderly Patients

Renal Function Monitoring

• Unlike many antibiotics that require dose reduction in renal impairment, the FDA labeling for Augmentin does not specify renal dose adjustments. 1 This contrasts with other antimicrobials where elderly patients require significant modifications (e.g., amantadine should not exceed 100 mg daily in patients >65 years due to declining renal function) 2.

Hepatic Monitoring

• Hepatically impaired patients should be dosed with caution and hepatic function monitored at regular intervals. 1 This is particularly important in elderly patients who may have concurrent liver dysfunction.

Alternative Formulations for Swallowing Difficulties

Adults with difficulty swallowing may use 1:

• 125 mg/31.25 mg per 5 mL or 250 mg/62.5 mg per 5 mL suspension in place of the 500 mg/125 mg tablet
• 200 mg/28.5 mg per 5 mL or 400 mg/57 mg per 5 mL suspension in place of the 875 mg/125 mg tablet

Clinical Evidence in Elderly Populations

A pilot study in hospitalized patients with mean age 67 years demonstrated good clinical response in 77% of patients treated with 500 mg amoxicillin + 250 mg clavulanic acid every 8 hours for 7 days. 3 Importantly, pharmacokinetic data showed that peak levels of both amoxicillin and clavulanic acid in blood and sputum were achieved at later times in elderly patients compared to healthy young volunteers, though this did not require dose modification. 3

Common Pitfalls to Avoid

Tablet Substitution Errors

• Never substitute the 250 mg/125 mg tablet for the 250 mg/62.5 mg chewable tablet—they are NOT interchangeable due to different clavulanic acid content (125 mg vs 62.5 mg). 1

Gastrointestinal Side Effects

• Elderly patients may experience increased gastrointestinal side effects. 3 Consider the twice-daily 875 mg/125 mg regimen over three-times-daily dosing to reduce diarrhea. 1

Duration of Therapy

• Standard treatment duration is 7-10 days for most respiratory infections. 4, 3 Shorter courses may lead to treatment failure, particularly in elderly patients with chronic lung disease.

Practical Dosing Algorithm

1. Assess severity of infection:

   • Mild-moderate infections: 500 mg/125 mg every 12 hours 1
   • Severe or respiratory infections: 875 mg/125 mg every 12 hours 1

2. Evaluate hepatic function:

   • If impaired: Use with caution and monitor regularly 1
   • If normal: Proceed with standard dosing

3. Consider gastrointestinal tolerance:

   • Prefer 875 mg/125 mg twice daily over 500 mg/125 mg three times daily to minimize diarrhea 1

4. Monitor for clinical response:

   • Expect peak drug levels to occur later than in younger patients 3
   • Continue therapy for full 7-10 day course 4, 3