Can a child with an allergy to amoxicillin (amoxicillin) take cefdinir (cefdinir)?

Cefdinir Safety in Children with Amoxicillin Allergy

Yes, children with amoxicillin allergy can generally receive cefdinir safely, as cefdinir has a different side chain structure than amoxicillin, making cross-reactivity uncommon. 1

Understanding Cross-Reactivity Between Penicillins and Cephalosporins

The risk of cross-reactivity between penicillins (like amoxicillin) and cephalosporins (like cefdinir) depends on several factors:

• Side chain similarity: Cross-reactivity is primarily determined by similarity in side chain structures, not the beta-lactam ring itself 1
• Type of previous reaction: The nature of the previous allergic reaction to amoxicillin matters
• Time since reaction: More recent reactions may pose higher risk

Risk Assessment

• Cross-reactivity between penicillins and cephalosporins with dissimilar side chains (like cefdinir) occurs in less than 5% of patients 1
• The overall risk of a reaction when giving a cephalosporin to a patient with penicillin allergy is approximately 0.1% 1

Clinical Recommendations

For children with amoxicillin allergy:

1. Determine reaction type:

   • Immediate-type reactions (urticaria, angioedema, anaphylaxis occurring within hours)
   • Delayed-type reactions (rash developing after >24 hours)

2. Management approach:

   • For immediate-type reactions: Cefdinir can be safely administered without prior testing 1
   • For delayed-type reactions: Cefdinir can be administered safely as it has dissimilar side chains to amoxicillin 1

3. Special precautions:

   • The FDA label for cefdinir states that careful inquiry about previous hypersensitivity reactions should be made 2
   • Cross-hypersensitivity among β-lactam antibiotics may occur in up to 10% of patients with penicillin allergy 2

Clinical Evidence Supporting Safety

• A retrospective study of 173 pediatric patients with history of penicillin allergy found only one adverse reaction (0.7%) to a cephalosporin, and this was in a patient with negative penicillin skin test 3
• None of the patients with confirmed penicillin allergy who received cephalosporins had adverse reactions 3

Practical Considerations for Otitis Media Treatment

When treating acute otitis media in a child with amoxicillin allergy:

• Cefdinir is an appropriate alternative at a dose of 14 mg/kg/day divided into two doses for 10 days 4, 5
• Cefdinir has good coverage against common otitis media pathogens including H. influenzae, M. catarrhalis, and penicillin-susceptible S. pneumoniae 6

Important Cautions

• Monitor for signs of allergic reaction when administering cefdinir to a child with amoxicillin allergy
• Be aware that cefdinir may cause red stools when co-administered with iron-containing products (including infant formulas) due to formation of a non-absorbable complex 7
• If an allergic reaction occurs, discontinue cefdinir immediately and provide appropriate emergency treatment 2

Bottom Line

Cefdinir is generally safe for children with amoxicillin allergy and is an effective alternative for treating conditions like acute otitis media. The risk of cross-reactivity is low due to the dissimilar side chain structures between amoxicillin and cefdinir.