What is the recommended dose of Cefaclor (Cephalosporin) for adults and children?

Cefaclor Recommended Dosing

For adults, cefaclor is dosed at 250 mg orally every 8 hours for mild infections, doubling to 500 mg every 8 hours for more severe infections or less susceptible organisms; for children, the standard dose is 20 mg/kg/day divided every 8 hours, increasing to 40 mg/kg/day (maximum 1 g/day) for more serious infections including otitis media. 1

Adult Dosing

• Standard dose: 250 mg orally every 8 hours for routine susceptible infections 1
• Severe infections: 500 mg orally every 8 hours for pneumonia or infections caused by less susceptible organisms 1
• The medication should be administered orally, and absorption is delayed when taken with food 2

Pediatric Dosing

Standard Dosing (20 mg/kg/day)

• 20 mg/kg/day divided every 8 hours for routine infections including pharyngitis and mild soft tissue infections 1
• For a 9 kg child: 2.5 mL (½ teaspoon) of 125 mg/5 mL suspension three times daily 1
• For an 18 kg child: 5 mL (1 teaspoon) of 125 mg/5 mL suspension three times daily, or 2.5 mL of 250 mg/5 mL suspension three times daily 1

Higher Dosing (40 mg/kg/day)

• 40 mg/kg/day divided every 8 hours for more serious infections, otitis media, and infections caused by less susceptible organisms 1
• Maximum daily dose: 1 gram per day regardless of weight 1
• For a 9 kg child: 5 mL (1 teaspoon) of 125 mg/5 mL suspension three times daily, or 2.5 mL of 250 mg/5 mL suspension three times daily 1
• For an 18 kg child: 5 mL (1 teaspoon) of 250 mg/5 mL suspension three times daily 1

Alternative Twice-Daily Dosing

• For otitis media and pharyngitis only, the total daily dose may be divided and given every 12 hours instead of every 8 hours 1
• This provides a more convenient dosing schedule while maintaining efficacy for these specific infections 1

Clinical Applications

Demonstrated Efficacy

• Urinary tract infections in adults and children 2
• Upper and lower respiratory tract infections 2
• Skin and soft tissue infections with 90% favorable clinical and bacteriological responses 3
• Pediatric otitis media 2
• Streptococcal pharyngitis with superior bacteriologic eradication compared to penicillin V (96.6% vs 80.4% success rate) 4

Spectrum of Activity

• Active against beta-lactamase-producing Haemophilus influenzae resistant to ampicillin 2, 3
• Covers Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes 3
• More susceptible organisms include Escherichia coli, Klebsiella spp., Proteus mirabilis, and Salmonella spp. compared to cephalexin 2

Important Clinical Considerations

Duration of Therapy

• Minimum 10 days for beta-hemolytic streptococcal infections to prevent rheumatic fever 1
• Standard course is 5-10 days for most other infections 5

Renal Impairment

• Cefaclor may be administered without dosage adjustment in patients with impaired renal function, as elimination is primarily renal but the standard dose remains unchanged 1

Safety Profile

• Adverse reactions are mostly gastrointestinal, generally mild, and occur infrequently (approximately 5% of patients) 5
• Hepatic, renal, and hematopoietic studies show minimal adverse effects except occasional eosinophilia without clinical hypersensitivity 3

Common Pitfall

• The 20 mg/kg/day pediatric dose may be inadequate for otitis media; use 40 mg/kg/day for this indication 2
• Food delays absorption, so timing relative to meals should be considered for optimal efficacy 2