WHEN TO USE ORAL CEPHALOSPORINS AND WHICH ONE?! ─ As a pharmacist, you should know that cephalosporins are NOT first-line for many OUTpatient infections anymore.
Oral FIRST-generation agents, such as cephalexin (Keflex, Ceporex, etc) are known for their gram-positive coverage, but have little gram-negative coverage. Recommend cephalexin (Ceporex) for outpatient skin infections IF MRSA isn't suspected. For possible MRSA, recommend TMP/SMX (Septrin DS) or doxycycline.
Oral SECOND-generation agents, such as cefprozil (Cefzil, etc) cover Strep pneumoniae and H. influenzae. Suggest saving them for specific situations due to resistance concerns. For example, consider suggesting them for bacterial upper respiratory tract infection (otitis media, bronchitis and sinusitis) in patients allergic to penicillins. Discourage using cefaclor (Ceclor), it doesn't cover common pathogens.
Oral THIRD-generation agents, such as cefpodoxime (Podacef, etc) add even more gram-negative activity, but they don't reliably cover INpatient gram-negatives such as Enterobacter or Pseudomonas aeruginosa. There's overlap between 2nd- and 3rd-generation agents for respiratory tract infections. Explain that cefpodoxime (Podacef) or cefdinir (Omnicef, Cefdin) can be used for the same infections as cefprozil. Recommend cefixime (Suprax, Ximacef) only for gonorrhea, and only when an oral medication is necessary (can be combined with azithromycin). It has other indications, but is NOT the best choice.
Don't automatically avoid cephalosporins in penicillin-allergic patients. Cross-reactivity between penicillins and cephalosporins is less than 1% instead of 10% as previously thought. And it's less likely with 2nd- and 3rd-generation cephalosporins than 1st-generation. Caution about using cephalosporins if the reaction to penicillin is severe (angioedema, bronchospasm, urticaria, anaphylaxis).
REFERENCES
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Pichichero ME. A review of evidence supporting the American Academy of Pediatrics recommendation for prescribing cephalosporin antibiotics for penicillin-allergic patients. Pediatrics. 2005 Apr;115(4):1048-57. Available at: https://publications.aap.org/pediatrics/article-abstract/115/4/1048/67630/A-Review-of-Evidence-Supporting-the-American?redirectedFrom=fulltext
Holten, K.B. and Onusko, E.M. (2013). Appropriate Prescribing of Oral Beta-Lactam Antibiotics. American Family Physician, [online] 62(3), pp.611–620. Available at: https://www.aafp.org/afp/2000/0801/p611.html
Pichichero ME. Use of selected cephalosporins in penicillin-allergic patients: a paradigm shift. Diagn Microbiol Infect Dis. 2007 Mar;57(3 Suppl):13S-18S. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0732889306004950?via%3Dihub