From the FDA Drug Label
DOSAGE AND ADMINISTRATION Ampicillin and sulbactam for injection may be administered by either the IV or the IM routes. 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 recommended dose of Unasyn (ampicillin-sulbactam) for pneumonia is 1.5 to 3 grams every 6 hours.
- The total dose of sulbactam should not exceed 4 grams per day.
- For pediatric patients 1 year of age or older, the recommended daily dose is 300 mg per kg of body weight administered via intravenous infusion in equally divided doses every 6 hours.
- Pediatric patients weighing 40 kg or more should be dosed according to adult recommendations 1.
From the Research
Unasyn (ampicillin/sulbactam) for pneumonia is typically dosed at 1.5-3 grams intravenously every 6 hours for adults, with the total daily dose ranging from 6-12 grams depending on the severity of infection, as supported by the most recent study 2.
Key Considerations
- For children, the recommended dose is 100-200 mg/kg/day of the ampicillin component, divided into 4 doses.
- Treatment duration is usually 7-14 days, depending on clinical response and the specific type of pneumonia.
- Dosage adjustments are necessary for patients with renal impairment, with reduced doses or extended intervals between doses when creatinine clearance is below 30 mL/min.
Efficacy and Safety
- Unasyn is effective against many respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and some anaerobes due to its combination of ampicillin (a beta-lactam antibiotic) and sulbactam (a beta-lactamase inhibitor) that prevents bacterial resistance, as shown in studies 3, 4.
- Common side effects include diarrhea, rash, and nausea.
- Patients should complete the full course of antibiotics even if symptoms improve before completion to ensure complete eradication of the infection and prevent antibiotic resistance.
Recent Findings
- A recent study 5 suggests that high dosage combination regimens may be required for the treatment of life-threatening infections in critically ill patients with ventilator-associated pneumonia.
- Another study 2 found that ampicillin/sulbactam plus macrolide may be more effective in the early phase of treatment for community-acquired pneumonia without risk factors for aspiration compared to ceftriaxone plus macrolide.