Can a patient with a history of allergic reactions to amoxicillin (amoxiclav) experience an allergic reaction to Imipenem?

From the Guidelines

A patient with a history of allergic reactions to amoxicillin (amoxiclav) may experience an allergic reaction to imipenem, but the risk is low, estimated to be around 1% or less, as suggested by the most recent and highest quality study 1. The cross-reactivity between penicillins and carbapenems is a concern due to their shared beta-lactam ring structure, which can trigger an immune response in some individuals. However, according to the 2022 practice parameter update on drug allergy 1, the overall reported incidence of carbapenem allergy is 0.3%, and the risk of cross-reactivity between carbapenems and other beta-lactams is also low. The study suggests that in patients with a history of penicillin or cephalosporin allergy, a carbapenem may be administered without testing or additional precautions, with a conditional recommendation and moderate certainty of evidence. For patients with mild reactions to amoxicillin, imipenem might be used with caution, potentially with close monitoring or desensitization protocols. However, for patients with severe reactions, imipenem should generally be avoided, and alternative non-beta-lactam antibiotics should be considered, as supported by other recent guidelines 1. Key points to consider include:

• The risk of cross-reactivity between penicillins and carbapenems is low, but not negligible.
• Patients with a history of severe allergic reactions to penicillins should be approached with caution when considering carbapenem use.
• Recent guidelines suggest that carbapenems can be used in patients with a history of penicillin or cephalosporin allergy, but with careful consideration of the individual patient's risk factors and medical history. In clinical practice, the decision to use imipenem in a patient with a history of allergic reactions to amoxicillin should be made on a case-by-case basis, taking into account the severity of the previous reaction, the potential benefits and risks of imipenem use, and the availability of alternative treatment options.

From the FDA Drug Label

Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients receiving therapy with beta-lactams. These reactions are more likely to occur in individuals with a history of sensitivity to multiple allergens There have been reports of individuals with a history of penicillin hypersensitivity who have experienced severe hypersensitivity reactions when treated with another beta-lactam. Before initiating therapy with Imipenem and Cilastatin for Injection (I.V.), careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, other beta-lactams and other allergens.

Allergic Reactions to Imipenem: A patient with a history of allergic reactions to amoxicillin (amoxiclav) may be at risk of experiencing an allergic reaction to Imipenem, as both are beta-lactam antibiotics.

• Key Considerations:
  • History of sensitivity to multiple allergens
  • Previous hypersensitivity reactions to penicillins, cephalosporins, or other beta-lactams
• Recommendation: Careful inquiry should be made concerning previous hypersensitivity reactions before initiating therapy with Imipenem and Cilastatin for Injection (I.V.) 2, 2, 2.

From the Research

Allergic Reactions to Amoxicillin and Imipenem

• A patient with a history of allergic reactions to amoxicillin (amoxiclav) may experience an allergic reaction to Imipenem, but the likelihood is low 3.
• Imipenem is a carbapenem antibiotic, and the risk of cross-reactivity between penicillins (such as amoxicillin) and carbapenems is generally low, with a reported risk of 0.87% (95% CI, 0.32-2.32) 3.
• However, it is essential to note that the risk of cross-reactivity can vary depending on the specific antibiotic and the individual patient's allergy profile.
• Studies have shown that patients with a proven IgE- or T-cell-mediated penicillin allergy have a higher risk of cross-reactivity to certain cephalosporins, but the risk is still relatively low for carbapenems like Imipenem 3.
• In some cases, patients may develop selective hypersensitivity reactions to amoxicillin or clavulanic acid, and these reactions can be maintained even after repeated administration of penicillin derivatives 4.

Cross-Reactivity and Selective Hypersensitivity

• Cross-reactivity between penicillins and carbapenems is thought to be related to the similarity in their chemical structures, particularly the R1 side chain 3.
• Selective hypersensitivity reactions to amoxicillin or clavulanic acid can occur, and these reactions can be diagnosed using skin tests and drug provocation tests 5, 4, 6.
• Patients with selective hypersensitivity reactions to amoxicillin or clavulanic acid may still be able to tolerate other penicillin derivatives, such as penicillin G or penicillin V 4.

Diagnosis and Management

• Diagnosis of allergic reactions to amoxicillin or Imipenem typically involves a combination of medical history, skin tests, and drug provocation tests 5, 3, 7.
• Management of patients with a history of allergic reactions to amoxicillin or Imipenem requires careful consideration of the individual patient's allergy profile and the potential risks and benefits of using these antibiotics 3, 7.