What is the coverage and dosage of cefdinir for treating bacterial infections?

Cefdinir Coverage and Dosage for Bacterial Infections

Antimicrobial Spectrum

Cefdinir is an extended-spectrum semisynthetic oral third-generation cephalosporin effective against many common bacterial pathogens causing respiratory tract and skin infections. It provides good coverage against respiratory pathogens including Haemophilus influenzae, Moraxella catarrhalis, and penicillin-susceptible Streptococcus pneumoniae 1, 2.

Gram-Positive Coverage:

• Staphylococcus aureus (methicillin-susceptible strains only) 3
• Streptococcus pneumoniae (penicillin-susceptible strains only) 3
• Streptococcus pyogenes 3
• Streptococcus agalactiae (in vitro activity) 3
• Viridans group streptococci (in vitro activity) 3

Gram-Negative Coverage:

• Haemophilus influenzae 3
• Haemophilus parainfluenzae 3
• Moraxella catarrhalis 3
• Citrobacter koseri (in vitro activity) 3
• Escherichia coli (in vitro activity) 3
• Klebsiella pneumoniae (in vitro activity) 3
• Proteus mirabilis (in vitro activity) 3

Antimicrobial Properties:

• Stable to hydrolysis by many common beta-lactamases, retaining activity against beta-lactamase-producing strains of H. influenzae and M. catarrhalis 2
• Activity against S. pneumoniae comparable to second-generation cephalosporins like cefuroxime axetil and cefpodoxime proxetil 1
• Activity against H. influenzae similar to cefuroxime axetil but lower than cefpodoxime proxetil 1

Important Limitations:

• Inactive against most strains of Enterobacter spp., Pseudomonas spp., Enterococcus spp., penicillin-resistant streptococci, and methicillin-resistant staphylococci 3
• Beta-lactamase negative, ampicillin-resistant (BLNAR) H. influenzae strains are typically non-susceptible 3

Dosage Recommendations

Adult and Adolescent Dosing:

• Standard adult dose: 300 mg twice daily or 600 mg once daily 3, 4
• Duration: 5-10 days depending on infection type 4

Pediatric Dosing (6 months through 12 years):

• Standard pediatric dose: 14 mg/kg/day, divided as either 7 mg/kg twice daily or 14 mg/kg once daily 3
• Maximum daily dose: 600 mg 3
• Once-daily dosing is as effective as twice-daily dosing for most infections 3
• For skin infections, twice-daily dosing is recommended 3

Specific Infection Types and Duration:

• Acute Bacterial Otitis Media: 5-10 days 3
• Acute Maxillary Sinusitis: 10 days 3
• Pharyngitis/Tonsillitis: 5-10 days 3
• Uncomplicated Skin and Skin Structure Infections: 10 days 3
• Community-acquired pneumonia: 10 days 4
• Acute bacterial exacerbation of chronic bronchitis: 10 days 4

Dosage Adjustments:

• For adults with creatinine clearance <30 mL/min: 300 mg once daily 3
• For pediatric patients with creatinine clearance <30 mL/min/1.73 m²: 7 mg/kg (up to 300 mg) once daily 3
• For hemodialysis patients: 300 mg or 7 mg/kg every other day with an additional dose after each hemodialysis session 3

Clinical Applications

Respiratory Tract Infections:

• Recommended for acute bacterial rhinosinusitis in patients who have not received antibiotics in the previous 4-6 weeks 1
• Effective for acute otitis media, pharyngitis/tonsillitis, and sinusitis 3, 5
• Considered for community-acquired pneumonia and acute bacterial exacerbation of chronic bronchitis 4

Skin and Skin Structure Infections:

• Effective for uncomplicated skin and skin structure infections 3, 6
• Clinical cure rates comparable to cephalexin in skin infections 6

Comparative Efficacy:

• In mathematical modeling for acute bacterial rhinosinusitis, cefdinir showed predicted clinical efficacy of 82-87% in children and 83-88% in adults 1
• Efficacy comparable to amoxicillin/clavulanate and levofloxacin in acute bacterial rhinosinusitis 5

Practical Considerations

Administration:

• Can be administered without regard to meals 3
• Available as oral suspension (125 mg/5 mL and 250 mg/5 mL) and capsules 3
• Suspension can be stored at room temperature for 10 days after reconstitution 3

Advantages:

• Convenient once or twice-daily dosing 4, 2
• Good tissue penetration in respiratory tract, skin, and middle ear 4, 2
• Oral suspension has superior taste compared to other antibiotics, improving adherence in pediatric patients 4, 5

Adverse Effects:

• Most common adverse effect is diarrhea 2, 6
• Generally well-tolerated with adverse event profile similar to comparator agents 2

Clinical Decision Making

When selecting cefdinir for treatment, consider:

1. For respiratory infections in adults with no recent antibiotic use:

   • Cefdinir is appropriate for mild disease 1
   • Alternative options include amoxicillin/clavulanate, amoxicillin, cefpodoxime proxetil, or cefuroxime axetil 1

2. For respiratory infections in children with no recent antibiotic use:

   • High-dose amoxicillin/clavulanate, amoxicillin, cefpodoxime proxetil, cefuroxime axetil, or cefdinir are all appropriate 1

3. For patients with beta-lactam allergies:

   • If non-immediate hypersensitivity reaction, cefdinir may be used 1
   • For immediate Type I hypersensitivity reactions, alternative classes should be considered 1

4. For skin infections:

   • Twice-daily dosing is recommended rather than once-daily 3
   • 10-day treatment duration is standard 3

When choosing between cephalosporins, cefdinir offers a balance of broad spectrum activity, convenient dosing, and good palatability, making it particularly valuable for pediatric patients and those requiring good compliance with oral therapy. 4, 2