Can a patient with an allergy to penicillin (pnc) receive meropenem?

Meropenem Can Be Safely Administered to Patients with Penicillin Allergy

Yes, patients with penicillin allergy can receive meropenem without prior allergy testing or special precautions in the vast majority of cases. The cross-reactivity rate between penicillins and carbapenems is extremely low at only 0.87% (95% CI: 0.32%-2.32%), making meropenem a safe alternative even for patients reporting anaphylactic reactions to penicillin 1.

Guideline-Based Recommendations

Current practice guidelines from major allergy societies recommend administering carbapenems (including meropenem) to penicillin-allergic patients without testing or additional precautions 1. This represents a conditional recommendation with moderate certainty of evidence from the 2022 Joint Task Force on Practice Parameters 1.

• The Dutch Working Party on Antibiotic Policy (SWAB) similarly recommends that any carbapenem can be used in patients with suspected immediate-type penicillin allergy, regardless of severity or time since the index reaction 1.
• These recommendations apply to both immediate-type (IgE-mediated) and non-severe delayed-type penicillin allergies 1.

Supporting Clinical Evidence

The extremely low cross-reactivity rate is supported by multiple lines of evidence:

• A systematic review of 1,127 patients demonstrated only 0.87% cross-reactivity between penicillins and any carbapenem 1.
• Among 295 patients with positive penicillin skin tests, only 1 patient (0.3%) had a potentially IgE-mediated reaction to carbapenems 1.
• A prospective study of 211 patients with skin test-confirmed penicillin allergy showed that all patients tolerated carbapenems without adverse reactions 1.
• Real-world clinical experience documented 110 patients with both non-anaphylactic and anaphylactic penicillin reactions who tolerated meropenem therapy (1-4 weeks) without any allergic reactions 2.

Practical Clinical Approach

Administer meropenem directly without delay when clinically indicated 1, 3:

• No penicillin skin testing is required before meropenem administration 1, 2.
• No graded dosing challenge is necessary for routine cases 1.
• Monitor for hypersensitivity reactions during the first dose, particularly in patients with a history of severe reactions 3.

Special Circumstances Requiring Caution

Consider a graded drug challenge or additional monitoring in 1:

• Patients with multiple drug allergies
• Patients with significant anxiety about receiving the medication
• Patients with severe delayed cutaneous reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis) or organ-involved reactions to penicillins

Common Pitfalls to Avoid

Do not unnecessarily avoid meropenem in penicillin-allergic patients, as this leads to:

• Use of less effective second-line antibiotics 4
• Increased antibiotic resistance 4
• Suboptimal patient outcomes 1

Do not confuse carbapenem cross-reactivity with cephalosporin cross-reactivity 1:

• Cephalosporins have a higher cross-reactivity rate (~2-4%) with penicillins compared to carbapenems (0.87%) 1, 5
• The structural differences between carbapenems and penicillins result in minimal immunologic cross-recognition 1

Bedside Allergy Assessment Option

For hospitalized patients requiring urgent meropenem therapy, bedside allergy assessment has proven safe and effective 4:

• A study of 182 inpatients with penicillin allergy labels showed 96.4% tolerated meropenem after bedside testing 4
• Only 2 patients had positive drug challenge tests, both with non-severe cutaneous reactions that resolved with treatment 4
• This approach avoids delays in appropriate antibiotic therapy while maintaining safety 4