Can patients with a penicillin allergy take Invanz (Ertapenem)?

Patients with Penicillin Allergy Can Safely Take Invanz (Ertapenem)

Yes, patients with penicillin allergy can safely take Invanz (ertapenem) without prior testing or additional precautions in most cases. 1

Cross-reactivity Between Penicillin and Carbapenems

Evidence Supporting Safety

• Recent guidelines strongly support the safety of carbapenems in penicillin-allergic patients:
  • The 2022 Drug Allergy Practice Parameter Update states that patients with penicillin or cephalosporin allergy histories can receive carbapenems without prior testing or additional precautions (conditional recommendation, moderate certainty of evidence) 1
  • A systematic review of 11 observational studies including 1127 patients demonstrated a risk of cross-reactivity to any carbapenem of only 0.87% (95% CI: 0.32%-2.32%) 1
  • A prospective study of 211 patients with skin test-confirmed penicillin allergy demonstrated that all tolerated carbapenems 1

Considerations Based on Allergy Type

• For immediate-type penicillin allergies (IgE-mediated):

  • The Dutch Working Party on Antibiotic Policy (SWAB) recommends that patients with suspected immediate-type penicillin allergy, regardless of severity or time since reaction, can receive any carbapenem without prior allergy testing (strong recommendation, low quality of evidence) 1

• For delayed-type penicillin allergies:

  • Carbapenems can be safely administered without prior testing unless there is a history of severe delayed cutaneous or organ-involved reaction 1

FDA Labeling Considerations

The FDA label for ertapenem states:

• "Ertapenem is contraindicated in patients with known hypersensitivity to any component of this product or to other drugs in the same class or in patients who have demonstrated anaphylactic reactions to beta-lactams" 2
• "Before initiating therapy with ertapenem, careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, other beta-lactams and other allergens" 2

Special Situations and Precautions

When Additional Caution May Be Warranted

• In patients with:
  • Multiple drug allergies
  • Significant anxiety about receiving a carbapenem
  • History of severe non-IgE-mediated reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis)

In these cases, a graded drug challenge might be preferred 1

Monitoring During Administration

• Monitor for signs of hypersensitivity reactions, especially during first administration
• Have emergency medications and equipment available as a precaution

Alternatives If Ertapenem Cannot Be Used

If a patient has a documented severe reaction to both penicillins and carbapenems:

• Aztreonam is a safe alternative that does not cross-react with penicillins 1
• Non-beta-lactam antibiotics may be considered based on the specific infection being treated

Common Pitfalls to Avoid

• Overestimation of cross-reactivity: Historical studies overestimated the risk of cross-reactivity between penicillins and carbapenems 3
• Unnecessary avoidance: Avoiding carbapenems in penicillin-allergic patients may lead to use of less effective or more toxic alternative antibiotics
• Failure to distinguish allergy types: Different types of allergic reactions (immediate vs. delayed) have different implications for cross-reactivity risk

In conclusion, current evidence strongly supports that ertapenem can be safely administered to patients with penicillin allergy in most clinical scenarios without prior testing or special precautions.