What is the appropriate dosage and treatment plan for cefdinir (Cefdinir) in adults and children with respiratory infections, particularly those caused by bacterial pathogens?

Cefdinir for Respiratory Infections

Cefdinir is an effective oral cephalosporin for bacterial respiratory infections, dosed at 300 mg twice daily or 600 mg once daily in adults for 5-10 days, and 14 mg/kg/day (maximum 600 mg) in children, with excellent coverage against common respiratory pathogens including S. pneumoniae and H. influenzae. 1

Dosing Regimens

Adults and Adolescents

• Standard dose: 300 mg twice daily OR 600 mg once daily 1
• Duration: 5-10 days depending on infection type 1
• Renal adjustment: For creatinine clearance <30 mL/min, reduce to 300 mg once daily 1
• Hemodialysis patients: 300 mg every other day, with an additional 300 mg dose after each dialysis session 1

Pediatric Patients (≥6 months)

• Total daily dose: 14 mg/kg/day, maximum 600 mg/day 1
• Dosing options: 7 mg/kg every 12 hours OR 14 mg/kg once daily 1
• Duration: 5-10 days for most respiratory infections; 10 days for acute maxillary sinusitis 1
• Important exception: Skin infections require twice-daily dosing (once-daily not studied) 1

Antimicrobial Spectrum and Clinical Positioning

Cefdinir provides comparable activity to second-generation cephalosporins against S. pneumoniae and similar activity to cefuroxime axetil against H. influenzae, though it is less active than cefpodoxime proxetil against H. influenzae. 2

Key Microbiologic Characteristics

• Gram-positive coverage: Good activity against penicillin-susceptible S. pneumoniae, comparable to cefuroxime axetil and cefpodoxime proxetil 2
• Gram-negative coverage: Effective against H. influenzae and M. catarrhalis, including β-lactamase-producing strains 3
• β-lactamase stability: Stable to hydrolysis by 13 common β-lactamases 4
• Pharmacokinetics: Not appreciably metabolized; eliminated principally via renal excretion with a half-life of approximately 1.5 hours 2, 4

Clinical Indications and Evidence

Acute Bacterial Rhinosinusitis

For adults with mild disease and no recent antibiotic use, cefdinir is an appropriate first-line option alongside amoxicillin/clavulanate, amoxicillin, cefpodoxime proxetil, and cefuroxime axetil. 2

• Clinical efficacy approximately 83-88% based on therapeutic outcomes modeling 2
• In comparative trials, cefdinir showed equivalent clinical and bacteriological efficacy to amoxicillin/clavulanate with approximately 90% cure rates 5
• Caused fewer adverse events requiring treatment discontinuation compared to amoxicillin/clavulanate 5

Pediatric Respiratory Infections

For children with mild disease and no recent antibiotic exposure, cefdinir is recommended as a first-line option, particularly valued for its excellent palatability in suspension form. 2

• Predicted clinical efficacy 82-87% in children with acute bacterial rhinosinusitis 2
• Cefdinir is the preferred agent among cephalosporins for children with non-serious penicillin hypersensitivity reactions based on patient acceptance 2
• The suspension formulation is very well accepted among children, improving adherence 2

Community-Acquired Pneumonia

Cefdinir is listed as an alternative oral cephalosporin option for S. pneumoniae pneumonia, though not preferred over amoxicillin for penicillin-susceptible strains. 2

• Demonstrated equivalent efficacy to cefprozil, loracarbef, cefuroxime axetil, and cefaclor in lower respiratory tract infections 3
• Achieves good tissue penetration in respiratory tract tissues and fluids 6

Important Clinical Considerations

When to Choose Cefdinir Over Alternatives

Select cefdinir when:

• Patient has non-Type I penicillin hypersensitivity (e.g., rash) 2
• Pediatric patient requires highly palatable suspension for adherence 2
• Once-daily dosing would improve compliance (except for skin infections) 1
• β-lactamase-producing H. influenzae or M. catarrhalis is suspected 3

When NOT to Use Cefdinir

Avoid cefdinir in favor of other agents when:

• Patient has moderate disease with recent antibiotic use (4-6 weeks): prefer respiratory fluoroquinolones or high-dose amoxicillin/clavulanate 2
• Drug-resistant S. pneumoniae (DRSP) is highly prevalent: cefpodoxime proxetil has superior H. influenzae coverage and is often preferred for treatment failures 2
• Patient requires coverage for MRSA or atypical pathogens: cefdinir lacks this activity 2

Common Pitfalls

• Diarrhea is the most common adverse event, occurring in approximately 20% of patients, though generally mild 5, 3
• Do not use once-daily dosing for skin infections in children—twice-daily dosing is required 1
• Cefdinir has no activity against drug-resistant S. pneumoniae (DRSP) 2
• Renal dose adjustment is mandatory for creatinine clearance <30 mL/min to prevent accumulation 1

Treatment Failure Protocol

If no clinical improvement occurs after 72 hours of cefdinir therapy:

• Switch to respiratory fluoroquinolone (levofloxacin, moxifloxacin, gatifloxacin) OR high-dose amoxicillin/clavulanate (4 g/250 mg per day in adults; 90 mg/6.4 mg per kg per day in children) 2
• Consider reevaluation with CT scan, fiberoptic endoscopy, or sinus aspiration and culture 2
• Recognize that cefdinir's limitations against H. influenzae (compared to cefpodoxime) may contribute to failure 2

Administration Details

• May be administered without regard to meals 1
• Suspension preparation: Tap bottle to loosen powder, add water in 2 portions, shake well after each addition 1
• Storage after reconstitution: Room temperature (25°C/77°F) in tightly closed container for up to 10 days; shake well before each use 1
• Avoid coadministration with antacids containing magnesium or aluminum, which impair absorption 2