Cefdinir vs. Keflex (Cephalexin) for Lung Infections

Comparison of Antimicrobial Activity

Cefdinir is an extended-spectrum semisynthetic cephalosporin with activity against S. pneumoniae comparable to second-generation agents, according to the American Academy of Otolaryngology-Head and Neck Surgery 1
Cefdinir has good activity against H. influenzae, a common respiratory pathogen, as noted by the American Academy of Otolaryngology-Head and Neck Surgery 1
Keflex (Cephalexin) is a first-generation cephalosporin with poor coverage for H. influenzae, making it inappropriate for respiratory infections, as stated by the American Academy of Allergy and Clinical Immunology 2
Keflex (Cephalexin) has limited activity against common respiratory pathogens compared to newer cephalosporins, according to the American Academy of Allergy and Clinical Immunology 2

Cefdinir's activity against S. pneumoniae is similar to cefuroxime axetil and cefpodoxime proxetil, which are recognized treatments for respiratory infections, as noted by the American Academy of Otolaryngology-Head and Neck Surgery 1
First-generation cephalosporins like cephalexin are not recommended for respiratory infections due to inadequate coverage of key respiratory pathogens, as stated by the American Academy of Allergy and Clinical Immunology 2

The suspension formulation of cefdinir is very well accepted among children, improving compliance, according to the American Academy of Otolaryngology-Head and Neck Surgery 1
Cefdinir is not appreciably metabolized and is eliminated principally via renal excretion, as noted by the American Academy of Otolaryngology-Head and Neck Surgery 1

For lung infections, cefdinir is preferred over cephalexin due to its broader spectrum against respiratory pathogens, as stated by the American Academy of Allergy and Clinical Immunology 2

Dose adjustment may be needed in patients with renal impairment as cefdinir is primarily eliminated via renal excretion, according to the American Academy of Otolaryngology-Head and Neck Surgery 1
For patients with suspected anaerobic involvement in severe or protracted cases, additional coverage may be needed, as noted by the American Academy of Allergy and Clinical Immunology 2