Can cefepime be given to a patient with a known allergy to amoxicillin (amoxicillin)

From the Guidelines

Cefepime can be given to a patient with a known allergy to amoxicillin, but it should be used with caution and careful monitoring, especially if the patient had a severe reaction to amoxicillin. The decision to administer cefepime to a patient with an amoxicillin allergy depends on the nature and severity of the previous allergic reaction.

• If the patient experienced a mild reaction to amoxicillin (such as a non-urticarial rash), cefepime may be administered with careful monitoring.
• However, if the patient had a severe reaction like anaphylaxis, angioedema, or Stevens-Johnson syndrome to amoxicillin, cefepime should generally be avoided due to potential cross-reactivity between beta-lactam antibiotics. The cross-reactivity between penicillins (like amoxicillin) and fourth-generation cephalosporins (like cefepime) is estimated to be around 1-3% 1. If cefepime is deemed necessary despite a history of severe penicillin allergy, consider consultation with an allergist for potential desensitization or performing skin testing before administration 1. During administration, ensure emergency medications and equipment are readily available to manage any potential allergic reactions. It's also important to note that the risk of cross-reactivity may be higher among drugs with similar side chains, and cefepime has a unique side chain that may reduce the risk of cross-reactivity 1.

From the FDA Drug Label

Before therapy with Cefepime Injection is instituted, careful inquiry should be made to determine whether the patient has had previous immediate hypersensitivity reactions to cefepime, cephalosporins, penicillins, or other beta-lactams Exercise caution if this product is to be given to penicillin-sensitive patients because cross-hypersensitivity among beta-lactam antibacterial drugs has been clearly documented and may occur in up to 10% of patients with a history of penicillin allergy.

Cefepime should be used with caution in patients allergic to amoxicillin, as there is a risk of cross-hypersensitivity among beta-lactam antibacterial drugs.

• The risk of cross-hypersensitivity is up to 10% in patients with a history of penicillin allergy.
• Careful inquiry should be made to determine whether the patient has had previous immediate hypersensitivity reactions to cefepime, cephalosporins, penicillins, or other beta-lactams before administering cefepime 2.

From the Research

Cefepime Administration in Amoxicillin-Allergic Patients

• Cefepime is a fourth-generation cephalosporin, and its use in patients allergic to amoxicillin is considered relatively safe due to its distinct side chain structure 3, 4, 5, 6.
• The overall cross-reactivity rate between penicillins and cephalosporins is approximately 1% when using first-generation cephalosporins or cephalosporins with similar R1 side chains 3.
• However, the cross-reactivity rate is negligible for third- or fourth-generation cephalosporins, such as cefepime, which have dissimilar side chains than the offending penicillin 3, 6.
• A study found that ceftriaxone, another fourth-generation cephalosporin, did not increase the risk of an allergic reaction in penicillin-allergic patients 5.
• It is essential to note that while the risk of cross-reactivity is low, it is not zero, and caution should be exercised when administering cefepime to patients with a known allergy to amoxicillin 7, 4.

Key Considerations

• The R1 side chain structure plays a crucial role in determining cross-reactivity between penicillins and cephalosporins 3, 7.
• Cefepime's distinct side chain structure reduces the risk of cross-reactivity with amoxicillin 3, 6.
• Patients with a history of non-serious, non-life-threatening penicillin reactions may be able to tolerate cefepime, but those with a history of severe reactions, such as anaphylaxis, should be approached with caution 4.