From the FDA Drug Label
The recommended adult dosage of ampicillin and sulbactam for injection is 1.5 grams (1 gram ampicillin as the sodium salt plus 0. 5 grams sulbactam as the sodium salt) to 3 grams (2 grams ampicillin as the sodium salt plus 1 gram sulbactam as the sodium salt) every six hours.
The dose of Unasyn (Ampicillin-Sulbactam) for a patient with a BMI of 37 is not directly addressed in the drug label. However, based on the provided information, the recommended adult dosage is 1.5 to 3 grams every 6 hours.
- The patient's BMI does not affect the dosing recommendations.
- The dosing is based on renal function and body weight for pediatric patients, but for adults, it is a standard dose. 1
From the Research
For a patient with a BMI of 37, the recommended Unasyn (ampicillin/sulbactam) dose is typically 3 grams (2 g ampicillin/1 g sulbactam) administered intravenously every 6 hours, as Unasyn does not typically require dose adjustment based on BMI alone 2.
Key Considerations
- The standard maximum daily dose is 12 grams (8 g ampicillin/4 g sulbactam) 3.
- Each dose should be infused over 15-30 minutes.
- For patients with renal impairment (creatinine clearance <30 mL/min), dose reduction or extended dosing intervals may be necessary, as the elimination half-lives of ampicillin and sulbactam increase significantly in patients with severe renal failure 3, 4.
- Monitor for adverse effects including gastrointestinal symptoms, rash, and potential Clostridium difficile-associated diarrhea.
- The combination of ampicillin (a beta-lactam antibiotic) with sulbactam (a beta-lactamase inhibitor) provides coverage against many gram-positive, gram-negative, and anaerobic bacteria, including some beta-lactamase producing strains.
Recent Evidence
- A recent study in 2023 found that continuous infusion of ampicillin/sulbactam resulted in therapeutic concentrations in critically ill patients, but patients with acute kidney injury exhibited significant higher serum concentrations 5.
- This study suggests that the described dosing regimen for ampicillin/sulbactam is safe with respect to the defined MIC breakpoints for ampicillin, and continuous subtherapeutic concentration is unlikely.
Clinical Implications
- Duration of therapy depends on the specific infection being treated, typically ranging from 5-14 days based on clinical response.
- It is essential to consider the patient's renal function when determining the dosing regimen, as impaired renal function can lead to drug accumulation 5.
- Close monitoring of the patient's condition and adjustment of the dosing regimen as needed is crucial to ensure optimal treatment efficacy and safety.