Does Omnicef (cefdinir) work for bacterial infections?

Effectiveness of Omnicef (Cefdinir) for Bacterial Infections

Omnicef (cefdinir) is effective against a wide range of bacterial infections, particularly respiratory tract infections and skin infections caused by susceptible organisms including Streptococcus pneumoniae (penicillin-susceptible strains), Haemophilus influenzae, and Moraxella catarrhalis. 1

Spectrum of Activity and Indications

• Cefdinir is an extended-spectrum semisynthetic oral third-generation cephalosporin with good activity against common respiratory pathogens 2
• FDA-approved indications include:
  • Community-acquired pneumonia
  • Acute exacerbations of chronic bronchitis
  • Acute maxillary sinusitis
  • Pharyngitis/tonsillitis
  • Uncomplicated skin and skin structure infections
  • Acute bacterial otitis media (in pediatric patients) 1

Antimicrobial Coverage

• Effective against:
  • Streptococcus pneumoniae (penicillin-susceptible strains only)
  • Haemophilus influenzae (including β-lactamase producing strains)
  • Moraxella catarrhalis (including β-lactamase producing strains)
  • Streptococcus pyogenes
  • Staphylococcus aureus (including β-lactamase producing strains) 1, 3
• Activity against S. pneumoniae is comparable to second-generation cephalosporins (e.g., cefuroxime axetil, cefpodoxime proxetil) 2
• Stable to hydrolysis by commonly occurring plasmid-mediated beta-lactamases, retaining activity against beta-lactamase-producing strains of H. influenzae and M. catarrhalis 3

Limitations of Coverage

• Not effective against penicillin-resistant Streptococcus pneumoniae (PRSP) 1
• Limited activity against some gram-negative organisms compared to other third-generation cephalosporins 2
• Not active against Pseudomonas aeruginosa 1
• Should not be used for infections suspected to be caused by resistant organisms outside its spectrum 1

Clinical Efficacy

• Clinical trials have demonstrated efficacy comparable to other antibiotics:
  • Similar efficacy to amoxicillin/clavulanate in acute bacterial rhinosinusitis with approximately 90% cure rates 4
  • Equivalent efficacy to cefprozil, loracarbef, cefuroxime axetil, and cefaclor in lower respiratory tract infections 3
  • As effective as penicillin V in streptococcal pharyngitis/tonsillitis and cefalexin in uncomplicated skin infections 3
• Convenient dosing of once or twice daily (300 mg twice daily or 600 mg once daily for adults) 5

Pharmacokinetic Advantages

• Good distribution into respiratory tract tissues and fluids, skin blisters, and ear fluids 5
• Not appreciably metabolized and primarily eliminated via renal excretion 2
• Half-life of approximately 1.5 hours, allowing for once or twice daily dosing 6
• Oral suspension formulation is well-accepted among children due to good taste 2

Important Considerations and Precautions

• Should only be used for proven or strongly suspected bacterial infections to reduce development of drug-resistant bacteria 1
• Dose adjustment required in patients with renal insufficiency (creatinine clearance <30 mL/min) 1
• Drug interactions:
  • Antacids containing magnesium or aluminum reduce absorption by approximately 40% - take cefdinir at least 2 hours before or after antacids 1
  • Iron supplements reduce absorption by up to 80% - take cefdinir at least 2 hours before or after iron supplements 1
• Most common adverse effect is diarrhea 3

Position in Treatment Algorithms

• Recommended as an alternative oral cephalosporin for treatment of Streptococcus pneumoniae infections 2
• Often used as an alternative when treatment with high-dose amoxicillin or amoxicillin/clavulanate fails or is not tolerated 2
• Particularly valuable in areas with high rates of beta-lactamase production in H. influenzae and where resistance to other commonly used agents has emerged 5

In conclusion, Omnicef (cefdinir) is an effective broad-spectrum antibiotic for treating susceptible bacterial infections, particularly respiratory tract and skin infections, with the convenience of once or twice daily dosing and good tolerability profile.