From the Guidelines
If you have an allergy to amoxicillin, you can generally take cefdinir, but caution is warranted, as the most recent and highest quality study suggests a very low risk of cross-reactivity between penicillins and third-generation cephalosporins like cefdinir 1.
Key Considerations
- Cefdinir is a cephalosporin antibiotic, which is structurally different from amoxicillin (a penicillin antibiotic) 1.
- The risk of cross-reactivity between penicillins and cephalosporins is lower than historically reported, with a recent study suggesting a reaction rate of 0.8% (95% CI: 0.13%-4.1%) among patients with confirmed penicillin allergy 1.
- The chemical structure of the cephalosporin determines the risk of cross-reactivity between specific agents, and cefdinir is highly unlikely to be associated with cross-reactivity with penicillin due to its distinct chemical structure 1.
Recommendations
- Before taking cefdinir, inform your healthcare provider about your amoxicillin allergy so they can assess your specific risk.
- Your healthcare provider may recommend starting with a test dose under medical supervision or suggest an entirely different class of antibiotics if your previous reaction was severe.
- Always report any new symptoms that develop while taking cefdinir, such as rash, itching, swelling, dizziness, or difficulty breathing, as these could indicate an allergic reaction requiring immediate medical attention.
Important Notes
- The Joint Task Force on Practice Parameters recommends a cephalosporin in cases without severe and/or recent penicillin allergy reaction history when skin test is not available 1.
- Skin testing is not recommended for routine use, but may be advisable for specific patients with multiple drug allergies due to the possibility of coexisting sensitivities 1.
From the FDA Drug Label
WARNINGS BEFORE THERAPY WITH CEFDINIR IS INSTITUTED, CAREFUL INQUIRY SHOULD BE MADE TO DETERMINE WHETHER THE PATIENT HAS HAD PREVIOUS HYPERSENSITIVITY REACTIONS TO CEFDINIR, OTHER CEPHALOSPORINS, PENICILLINS, OR OTHER DRUGS IF CEFDINIR IS TO BE GIVEN TO PENICILLIN-SENSITIVE PATIENTS, CAUTION SHOULD BE EXERCISED BECAUSE CROSS-HYPERSENSITIVITY AMONG β-LACTAM ANTIBIOTICS HAS BEEN CLEARLY DOCUMENTED AND MAY OCCUR IN UP TO 10% OF PATIENTS WITH A HISTORY OF PENICILLIN ALLERGY.
Patients with an allergy to amoxicillin, a type of penicillin, may be at risk of cross-hypersensitivity when taking cefdinir, as it is a β-lactam antibiotic.
- Caution should be exercised when administering cefdinir to patients with a history of penicillin allergy.
- The risk of cross-hypersensitivity may occur in up to 10% of patients with a history of penicillin allergy.
- Therefore, patients with an allergy to amoxicillin should be carefully evaluated before taking cefdinir 2.
From the Research
Allergy to Amoxicillin and Cefdinir
- Patients with an allergy to amoxicillin may be concerned about taking cefdinir, a type of cephalosporin antibiotic.
- Studies have shown that the cross-reactivity between penicillins (such as amoxicillin) and cephalosporins is lower than previously reported, with an overall cross-reactivity rate of approximately 1% when using first-generation cephalosporins or cephalosporins with similar R1 side chains 3.
- Cefdinir is a third-generation cephalosporin, which has a negligible risk of cross-allergy with penicillins, including amoxicillin 3, 4.
- The use of third- or fourth-generation cephalosporins, such as cefdinir, carries a negligible risk of cross-allergy in penicillin-allergic patients 3.
Safety of Cefdinir in Penicillin-Allergic Patients
- Cefdinir is considered safe for use in patients with a penicillin allergy, as it has a different chemical structure and a lower risk of cross-reactivity compared to first-generation cephalosporins 4.
- A study published in 2006 found that cefdinir does not increase the risk of an allergic reaction in patients with a penicillin allergy 4.
- Another study published in 2021 confirmed that avoiding β-lactam antibiotics, including cephalosporins, due to a penicillin allergy can result in worse long-term outcomes for patients, and that the risks of avoiding cephalosporins outweigh the benefits 5.