Can patients with a penicillin allergy take meropenem?

Meropenem Can Be Safely Administered to Patients with Penicillin Allergy

Patients with a history of penicillin allergy can safely receive meropenem without prior testing or additional precautions. 1 The risk of cross-reactivity between penicillins and carbapenems like meropenem is very low.

Evidence Supporting Meropenem Use in Penicillin-Allergic Patients

Guidelines and FDA Recommendations

• The 2022 practice parameter update on drug allergy from the Journal of Allergy and Clinical Immunology provides a conditional recommendation with moderate certainty of evidence that "in patients with a history of penicillin or cephalosporin allergy, a carbapenem may be administered without testing or additional precautions." 1

• While the FDA label for meropenem notes that hypersensitivity reactions can occur and recommends inquiring about previous hypersensitivity to penicillins and other β-lactams, it does not contraindicate meropenem in penicillin-allergic patients 2

Cross-Reactivity Data

• Clinical cross-reactivity between carbapenems and other β-lactams is low:

  • A systematic review of 838 patients with proven, suspected, or possible IgE-mediated penicillin allergy showed carbapenem reactions occurred in only 4.3% of patients 1
  • Among patients with positive skin tests to penicillin, only 0.3% had a potentially IgE-mediated reaction to carbapenems 1
  • A meta-analysis of 11 observational studies including 1127 patients demonstrated a risk of cross-reactivity to any carbapenem as only 0.87% 1

• A prospective study of 211 patients with skin test-confirmed penicillin allergy demonstrated that all tolerated carbapenems 1, 3

Clinical Approach to Meropenem Use in Penicillin-Allergic Patients

Algorithm for Decision-Making:

1. Assess the penicillin allergy history:

   • Type of reaction (immediate vs. delayed)
   • Severity of previous reaction
   • Time since reaction occurred

2. For all patients with penicillin allergy history:

   • Meropenem can be administered without prior testing 1, 3
   • This applies regardless of the severity of the previous penicillin reaction

3. Special considerations:

   • For patients with multiple drug allergies or significant anxiety about potential reactions, a graded drug challenge might be preferred 1
   • For patients with severe delayed cutaneous or organ-involved reactions to penicillin, exercise additional caution 1

Supporting Research Evidence

Multiple studies have confirmed the safety of meropenem in penicillin-allergic patients:

• Romano et al. (2007) found that only 1 out of 104 patients (0.9%) with documented IgE-mediated penicillin hypersensitivity had a positive skin test to meropenem, and all patients with negative skin tests tolerated meropenem challenges 4

• A 2008 study of 108 children with documented penicillin allergy showed only one subject (0.9%) had a positive skin test to meropenem, and all others tolerated challenges 5

• A prospective study of 110 patients with reported penicillin allergies (including 51 with anaphylactic reactions) found that all patients tolerated meropenem therapy without any allergic reactions 6

Common Pitfalls and Caveats

• Outdated concerns: Many clinicians still avoid carbapenems in penicillin-allergic patients based on outdated concerns about cross-reactivity. Current evidence supports their safe use.

• Documentation: Always document the decision-making process and rationale for using meropenem in a patient with penicillin allergy.

• Monitoring: While the risk is low, standard monitoring for any signs of hypersensitivity reaction is still prudent when first administering meropenem to patients with penicillin allergy.

• Drug interactions: Be aware that meropenem can interact with valproic acid, potentially reducing valproic acid concentrations and increasing seizure risk in patients on this medication 2

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