What is cefdinir?

Cefdinir: An Extended-Spectrum Oral Cephalosporin

Cefdinir is an extended-spectrum, semisynthetic oral cephalosporin antibiotic that is effective for treating mild to moderate bacterial infections of the respiratory tract and skin, with good activity against common pathogens and a favorable safety profile. 1

Pharmacological Properties

• Chemical Structure: Cefdinir is a third-generation cephalosporin with the chemical formula C₁₄H₁₃N₅O₅S₂ and molecular weight of 395.42 1
• Metabolism and Elimination: Not appreciably metabolized and primarily eliminated via renal excretion 2
• Administration: Available in oral formulations (capsules and suspension) 1
• Dosing Schedule: Can be administered once or twice daily, making it convenient for patients 3

Antimicrobial Spectrum

Cefdinir demonstrates activity against:

• Respiratory Pathogens:

  • Streptococcus pneumoniae (penicillin-susceptible strains only) 1
  • Haemophilus influenzae (including β-lactamase producing strains) 1
  • Moraxella catarrhalis (including β-lactamase producing strains) 1
  • Haemophilus parainfluenzae 1

• Other Common Pathogens:

  • Streptococcus pyogenes (Group A Streptococcus) 1
  • Staphylococcus aureus (including β-lactamase producing strains) 1

• Antimicrobial Resistance:

  • Stable to hydrolysis by commonly occurring plasmid-mediated β-lactamases 4
  • Not effective against drug-resistant S. pneumoniae (DRSP) 2

FDA-Approved Indications

For Adults and Adolescents:

• Community-acquired pneumonia
• Acute exacerbations of chronic bronchitis
• Acute maxillary sinusitis
• Pharyngitis/tonsillitis
• Uncomplicated skin and skin structure infections 1

For Pediatric Patients:

• Acute bacterial otitis media
• Pharyngitis/tonsillitis
• Uncomplicated skin and skin structure infections 1

Comparative Efficacy

• Activity against S. pneumoniae comparable to second-generation cephalosporins like cefuroxime axetil and cefpodoxime proxetil 2
• Activity against H. influenzae similar to cefuroxime axetil but lower than cefpodoxime proxetil 2
• More effective than cefaclor, which has poor activity against H. influenzae and no activity against DRSP 2
• Superior to cefixime and ceftibuten for acute bacterial sinusitis due to better activity against S. pneumoniae 2

Advantages and Clinical Considerations

• Palatability: The suspension formulation is very well accepted among children, with superior taste compared to other antibiotics like cefpodoxime proxetil 2, 5
• Safety Profile: Generally well tolerated with fewer serum sickness-like reactions compared to cefaclor 2
• Common Side Effects: Diarrhea is the most common adverse event but typically mild 4
• Alternative Use: Can be used as an alternative treatment for patients who fail or cannot tolerate high-dose amoxicillin or amoxicillin/clavulanate 5

Important Clinical Caveats

• Not effective against penicillin-resistant S. pneumoniae strains 1
• Should be used only for proven or strongly suspected bacterial infections to reduce development of drug-resistant bacteria 1
• Not studied for prevention of rheumatic fever following S. pyogenes pharyngitis/tonsillitis (only intramuscular penicillin has been demonstrated effective for this purpose) 1
• Dosage adjustment required in patients with renal impairment 1

Cefdinir represents an important oral antibiotic option for treating community-acquired infections, especially in areas with elevated rates of β-lactamase production in common pathogens and where resistance to other commonly used agents has emerged 3.