Amoxicillin-Clavulanate Dosing for Step-Down from Ceftriaxone 2g IV Daily in Hospital-Acquired Diarrhea
For an adult patient with hospital-acquired diarrhea being stepped down from ceftriaxone 2g IV daily, use amoxicillin-clavulanate 875 mg/125 mg orally every 12 hours, which provides equivalent antimicrobial coverage while reducing the risk of further diarrhea compared to continuing parenteral therapy. 1
Rationale for This Dosing Recommendation
The FDA-approved adult dosing for more severe infections and respiratory tract infections is amoxicillin-clavulanate 875 mg/125 mg every 12 hours, which provides adequate coverage for organisms typically treated with ceftriaxone 2g daily 1. This formulation delivers sufficient amoxicillin concentrations to overcome intermediately resistant pathogens while maintaining the clavulanate component needed for β-lactamase-producing organisms 1.
Key Considerations for Hospital-Acquired Diarrhea
Ceftriaxone itself causes diarrhea in approximately 34% of patients, with symptoms persisting for 2-8 days after onset, making it a likely contributor to the current clinical picture 2
Switching to oral amoxicillin-clavulanate allows for hospital discharge while maintaining antimicrobial efficacy, as demonstrated in multiple studies showing equivalent outcomes between oral step-down therapy and continued IV treatment 3, 4
The 875 mg/125 mg formulation should be taken at the start of meals to minimize gastrointestinal intolerance and enhance clavulanate absorption 1
Important Clinical Pitfalls to Avoid
Do not substitute two 250 mg/125 mg tablets for one 500 mg/125 mg tablet, as both contain the same amount of clavulanic acid (125 mg), making them non-equivalent 1. The 875 mg/125 mg tablet is the appropriate single-tablet formulation for step-down therapy.
Rule out Clostridium difficile infection before attributing diarrhea solely to ceftriaxone, particularly in hospitalized patients, though ceftriaxone-associated diarrhea is typically non-infectious in etiology 2.
Alternative Dosing if Standard Regimen Not Tolerated
If the patient develops significant diarrhea on the 875 mg/125 mg formulation, consider switching to the 500 mg/125 mg tablet every 8 hours, which provides similar daily amoxicillin dosing (3000 mg vs 3500 mg) but may be better tolerated with more frequent, smaller doses 1.
For patients with difficulty swallowing tablets, liquid suspension formulations (400 mg/57 mg per 5 mL) can substitute for the 875 mg/125 mg tablet, though this is rarely necessary in adults 1.
Duration of Therapy
Continue treatment for the same total duration as originally planned for the ceftriaxone course, typically 7-14 days depending on the underlying infection being treated 5. The step-down to oral therapy does not require extending the total antibiotic duration.