How often is Unasyn (Ampicillin-Sulbactam) IV administered for pneumonia (pneumonia)?

Unasyn (Ampicillin-Sulbactam) IV Dosing for Pneumonia

Unasyn (ampicillin-sulbactam) should be administered intravenously every 6 hours for pneumonia. 1

Dosing Recommendations

Standard Dosing

• Dose: 1.5-3g IV every 6 hours
  • This represents 1g ampicillin/0.5g sulbactam to 2g ampicillin/1g sulbactam
  • Total daily sulbactam dose should not exceed 4g
• Administration: Slow IV injection over 10-15 minutes or as infusion in 50-100mL compatible diluent over 15-30 minutes 1

Dosing Based on Pneumonia Severity

1. For moderate pneumonia (non-ICU hospitalized patients):

   • Ampicillin/sulbactam 1.5-3g IV every 6 hours 2
   • Often part of a β-lactam-based regimen that may include a macrolide for atypical coverage

2. For severe pneumonia (ICU patients):

   • Ampicillin/sulbactam 3g IV every 6 hours 2
   • May be combined with a macrolide or fluoroquinolone for broader coverage

Renal Dose Adjustments

For patients with impaired renal function, dose adjustment is required:

• CrCl >30 mL/min: 1.5-3g every 6-8 hours
• CrCl 15-29 mL/min: 1.5-3g every 12 hours
• CrCl 5-14 mL/min: 1.5-3g every 24 hours 1

Treatment Duration

• Standard treatment duration for pneumonia: 5-7 days 2
• For more severe cases or specific pathogens: 7-14 days 2
• Treatment should be individualized based on clinical response and pathogen

Important Considerations

• Monitoring: Assess clinical response after 48-72 hours to determine if therapy is effective
• Compatibility: When concomitant therapy with aminoglycosides is indicated, Unasyn and aminoglycosides should be reconstituted and administered separately due to in vitro inactivation 1
• Common pitfall: Underdosing in severe pneumonia - ensure adequate dosing for severe infections

Combination Therapy

For patients with risk factors for multidrug-resistant organisms (MDROs):

• Consider combination therapy with a macrolide or fluoroquinolone for broader coverage 2
• For suspected MRSA pneumonia, add appropriate MRSA coverage (vancomycin or linezolid) 2

Switching to Oral Therapy

Consider switching to oral therapy when:

• Patient has been afebrile for 48 hours
• Clinically stable (respiratory rate ≤24/min, heart rate ≤100/min, systolic BP ≥90 mmHg)
• Able to maintain oral intake
• Normal mental status 2

The evidence consistently supports administering Unasyn (ampicillin-sulbactam) every 6 hours for pneumonia, with dosage adjustments based on renal function and severity of infection. This dosing interval is supported by the FDA label and multiple pneumonia treatment guidelines.