Achieving 875mg Amoxicillin Dose Using Liquid Formulation
You cannot achieve an 875mg amoxicillin dose using the 400mg/57mg per 5ml suspension—this formulation is designed for pediatric dosing and does not provide a practical volume to reach 875mg. 1
Why the Liquid Formulation Doesn't Work for 875mg Dosing
To obtain 875mg of amoxicillin from the 400mg/57mg per 5ml suspension, you would need to administer approximately 10.9ml per dose, which is impractical and not a standard dosing volume 1
The FDA-approved 400mg/57mg per 5ml suspension is specifically indicated for pediatric patients and adults who have difficulty swallowing tablets, but it is designed to replace the 875mg tablet formulation, not to provide equivalent dosing through volume adjustment 1
Correct Approach for Adult Dosing
For adults requiring 875mg of amoxicillin, you should prescribe the 875mg/125mg tablet formulation taken twice daily, not attempt to use pediatric liquid formulations. 1
The standard adult dose for severe infections and respiratory tract infections is one 875mg/125mg tablet every 12 hours 1
If the patient truly cannot swallow tablets, the FDA label states that the 400mg/57mg per 5ml suspension "may be used in place of the 875mg/125mg tablet" for adults with swallowing difficulties, but this requires careful calculation and is not the preferred approach 1
When Liquid Formulations Are Appropriate
The 400mg/57mg per 5ml suspension is designed for pediatric patients aged 12 weeks or older weighing less than 40kg, dosed at 45mg/kg/day every 12 hours for more severe infections 1
For adults who genuinely cannot swallow tablets, prescribe the suspension with explicit instructions, but recognize this is a second-line approach due to volume and palatability concerns 1
Critical Prescribing Considerations
Never attempt to substitute two 250mg/125mg tablets for one 500mg/125mg tablet, as this results in excessive clavulanate dosing and increased gastrointestinal side effects 1
The 875mg tablet formulation provides the optimal amoxicillin-to-clavulanate ratio (7:1) for adult dosing, minimizing diarrhea while maintaining efficacy 2, 3
For respiratory infections in adults, the 875mg/125mg twice-daily regimen achieves superior pharmacodynamic coverage compared to attempting equivalent dosing with liquid formulations 2, 4