What is the primary concern between Augmentin (amoxicillin/clavulanate) 1000 mg and 875 mg dosages?

Differences Between Augmentin 1000 mg and 875 mg Dosages

The primary concern between Augmentin (amoxicillin/clavulanate) 1000 mg and 875 mg dosages is that the 1000 mg formulation provides higher amoxicillin concentration needed for resistant pathogens, particularly drug-resistant Streptococcus pneumoniae, while maintaining the same clavulanate component. 1

Formulation Differences

• Augmentin 875 mg contains 875 mg amoxicillin with 125 mg clavulanate, typically dosed twice daily for standard infections 2
• Augmentin 1000 mg (often called Augmentin XR in the US) contains 1000 mg amoxicillin with 62.5 mg clavulanate per tablet, designed to provide enhanced coverage against resistant pathogens 1

Clinical Indications and Applications

• Augmentin 875/125 mg is the standard formulation used for most common infections including:

  • Skin and soft tissue infections 2
  • Respiratory tract infections 2
  • Urinary tract infections 2
  • Animal or human bites 2

• Augmentin 1000 mg (XR) formulation is specifically developed for:

  • Treatment of respiratory infections caused by drug-resistant pathogens 1
  • Infections with S. pneumoniae with reduced penicillin susceptibility 1
  • Cases where higher amoxicillin concentrations are needed while limiting clavulanate exposure 1

Pharmacokinetic Considerations

• The 1000 mg formulation was pharmacokinetically enhanced to maintain higher blood levels of amoxicillin for longer periods 1
• Standard 875 mg formulation produces an AUC of approximately 35.4 ± 8.1 mcg•hr/mL and a Cmax of 13.8 ± 4.1 mcg/mL 3
• Higher amoxicillin doses are needed to achieve adequate time above MIC for resistant organisms 1

Side Effect Profile

• Both formulations share similar side effect profiles, with gastrointestinal effects being most common 1, 4
• The 875 mg formulation may have a higher relative proportion of clavulanate, which is associated with GI side effects 1
• Common side effects include:
  • Nausea (reported in approximately 9% of patients) 4
  • Diarrhea (reported in approximately 9% of patients) 4
  • Skin rash (reported in approximately 3% of patients) 4

Clinical Decision-Making

• Choose 875 mg formulation for:

  • Standard community-acquired infections 2
  • Patients with normal renal function 3
  • Empiric therapy for common infections 2

• Consider 1000 mg formulation for:

  • Areas with high prevalence of resistant S. pneumoniae 1
  • Persistent or recurrent infections not responding to standard therapy 1
  • Severe respiratory tract infections requiring higher amoxicillin concentrations 1

Special Populations

• For patients with renal impairment:
  • Dosage adjustment is required for severe renal impairment (GFR less than 30 mL/min) 3
  • Amoxicillin is primarily eliminated by the kidney 3
  • Hemodialysis can remove amoxicillin from circulation 3

Common Pitfalls

• Prescribing standard 875 mg formulation for infections likely caused by resistant pathogens 1
• Not considering local resistance patterns when selecting between formulations 1
• Failing to adjust dosing in patients with renal impairment 3
• Not completing the full course of therapy, which may lead to treatment failure and potential resistance development 2