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General
- Type: 1st generation cephalosporin
- Dosage forms
- Tabs: 250mg, 500mg, 750mg
- Liquid: 125mg/5mL; 250mg/5mL
- Common Trade Names: Keflex, Keftab, Biocef
Adult Dosing
General
- 250-500mg PO q6h
- Max: 4g/day
Uncomplicated UTI
- 500mg PO q12h x 7-14 days
Cellulitis and Other Skin Infections
- 60-120 kg: 500 mg Q6H 1 gram Q8H.
- >120 kg: 1 g Q6H. [1]
Pediatric Dosing
General
- 25-50mg/kg/day PO divided q6-12h
- Max: 500mg/dose
- 75-100mg/kg/day PO divided q12h x 10 days
- Max: 4,000mg/24h
- 75-100mg/kg/day PO divided q12h x 10 days
Streptococcal Pharyngitis (>1 Year)
- 40mg/kg/day PO divided q12h x 10 days
- Max: 500mg/dose
Skin Infections
- 25-50mg/kg/day PO divided q12h
- Max: 500mg/dose
Special Populations
- Pregnancy Rating: B
- Lactation risk categories: Enters breast milk/L3
- Renal
- Adult
- CrCl 50-90: give q6-8h
- CrCl 10-50: give q8-12h
- CrCl <10: give q12-24h
- Hemodialysis: give dose after dialysis, no supplement
- Peritoneal dialysis: no supplement
- Pediatric
- CrCl 30-50: give q8h
- CrCl 10-29: give q12h
- CrCl <10: give q24h
- Hemodialysis: give dose after dialysis, no supplement
- Peritoneal dialysis: no supplement
- Hepatic (Adult & Pediatric)
Contraindications
- Allergy to class/drug
- Caution advised with contraceptives
Adverse Drug Reactions
Serious
Common
Pharmacology
- Half-life: 1h (~20hr ESRD)
- Metabolism: Minimal
- Excretion: Primarily urine (>90% unchanged)
- Mechanism of Action:
- Bactericidal, inhibits cell wall
Key
- S susceptible/sensitive (usually)
- I intermediate (variably susceptible/resistant)
- R resistant (or not effective clinically)
- S+ synergistic with cell wall antibiotics
- U sensitive for UTI only (non systemic infection)
- X1 no data
- X2 active in vitro, but not used clinically
- X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
- X4 active in vitro, but not clinically effective for strep pneumonia
See Also
References
- ↑ Reduction of Inappropriate Antibiotic Use and Improved Outcomes by Implementation of an Algorithm-Based Clinical Guideline for Nonpurulent Skin and Soft Tissue Infections. Ann Emerg Med. 2020 Feb 13. pii: S0196-0644(19)31453-2. doi: 10.1016/j.annemergmed.2019.12.012. [Epub ahead of print]
- ↑ Sanford Guide to Antimicrobial Therapy 2014
- Sanford 2010
- Epocrates
- Lexicomp
