Drug Detail:Cephalexin (Cephalexin [ sef-a-lex-in ])
Drug Class: First generation cephalosporins
Usual Adult Dose for Otitis Media
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of otitis media caused by susceptible Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Streptococcus pyogenes, and Moraxella catarrhalis
Usual Adult Dose for Pharyngitis
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of skin and skin structure infections caused by susceptible gram-positive bacteria (e.g., S aureus, S pyogenes)
IDSA Recommendations:
Skin or soft tissue infections: 500 mg orally 4 times a day
Impetigo: 250 mg orally 4 times a day
Pharyngitis: 20 mg/kg orally 2 times a day
- Maximum dose: 500 mg/dose
- Duration of therapy: 10 days
Uses:
- Empirical treatment for nonpurulent cellulitis and diabetic foot infections caused by beta-hemolytic streptococci (e.g., methicillin-susceptible Staphylococcus aureus [MSSA], Streptococcus species)
- Treatment of skin or soft tissue infections caused by MSSA in patients who have penicillin allergies (except immediate hypersensitivity)
- Treatment of impetigo caused by Staphylococcus and Streptococcus species
- Treatment of Group A streptococcal pharyngitis in patients with penicillin allergy (except immediate hypersensitivity)
- Treatment of surgical site infections of the trunk/extremity away from the perineum or axilla
Usual Adult Dose for Skin or Soft Tissue Infection
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of skin and skin structure infections caused by susceptible gram-positive bacteria (e.g., S aureus, S pyogenes)
IDSA Recommendations:
Skin or soft tissue infections: 500 mg orally 4 times a day
Impetigo: 250 mg orally 4 times a day
Pharyngitis: 20 mg/kg orally 2 times a day
- Maximum dose: 500 mg/dose
- Duration of therapy: 10 days
Uses:
- Empirical treatment for nonpurulent cellulitis and diabetic foot infections caused by beta-hemolytic streptococci (e.g., methicillin-susceptible Staphylococcus aureus [MSSA], Streptococcus species)
- Treatment of skin or soft tissue infections caused by MSSA in patients who have penicillin allergies (except immediate hypersensitivity)
- Treatment of impetigo caused by Staphylococcus and Streptococcus species
- Treatment of Group A streptococcal pharyngitis in patients with penicillin allergy (except immediate hypersensitivity)
- Treatment of surgical site infections of the trunk/extremity away from the perineum or axilla
Usual Adult Dose for Osteomyelitis
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of bone infections caused by susceptible S aureus and Proteus mirabilis
Usual Adult Dose for Cystitis
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of genitourinary tract infections caused by susceptible Escherichia coli, P mirabilis, and Klebsiella pneumoniae
Usual Adult Dose for Prostatitis
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of genitourinary tract infections caused by susceptible Escherichia coli, P mirabilis, and Klebsiella pneumoniae
Usual Adult Dose for Pyelonephritis
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of genitourinary tract infections caused by susceptible Escherichia coli, P mirabilis, and Klebsiella pneumoniae
Usual Adult Dose for Upper Respiratory Tract Infection
250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of respiratory tract infections caused by susceptible S pneumoniae and S pyogenes
Usual Adult Dose for Bacterial Endocarditis Prophylaxis
American Heart Association (AHA) and Infectious Diseases Society of America (IDSA) Recommendations: 2 g orally as a single dose 30 to 60 minutes before the procedure
Use: Prevention of infective endocarditis in patients allergic to penicillins/ampicillins undergoing a dental procedure (except in immediate hypersensitivity)
Usual Adult Dose for Bacterial Infection
IDSA Recommendations: 500 mg orally 3 to 4 times a day
Uses:
- Preferred antimicrobial for chronic suppression of oxacillin-susceptible staphylococci
- Alternative antimicrobial for chronic suppression of beta-hemolytic streptococci or Propionibacterium species
Usual Pediatric Dose for Otitis Media
12.5 to 25 mg/kg orally every 6 hours
Usual Pediatric Dose for Pharyngitis
Over 1 year of age:
Streptococcal pharyngitis: 12.5 to 25 mg/kg orally every 12 hours
Usual Pediatric Dose for Skin or Soft Tissue Infection
12.5 to 25 mg/kg orally every 12 hours
Usual Pediatric Dose for Upper Respiratory Tract Infection
1 to 15 years:
Mild to moderate infections: 25 to 50 mg/kg orally per day, given in equally divided doses
Severe infections: 50 to 100 mg/kg orally per day, given in equally divided doses
Duration of therapy: 7 to 14 days
15 years and older: 250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Comment: Beta-hemolytic streptococcal infections should be treated for at least 10 days.
Use: Treatment of respiratory tract infections caused by susceptible S pneumoniae and S pyogenes
Pediatric Infectious Diseases Society (PIDS) and IDSA Recommendations:
Greater than 3 months:
Step-down therapy or mild infection: 75 to 100 mg/kg orally per day, in 3 to 4 divided doses
Use: Preferred treatment of community acquired pneumonia caused by MSSA
Usual Pediatric Dose for Osteomyelitis
15 years and older: 250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of bone infections caused by susceptible S aureus and P mirabilis
Usual Pediatric Dose for Cystitis
15 years and older: 250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of genitourinary tract infections caused by susceptible E coli, P mirabilis, and K pneumoniae
Usual Pediatric Dose for Prostatitis
15 years and older: 250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of genitourinary tract infections caused by susceptible E coli, P mirabilis, and K pneumoniae
Usual Pediatric Dose for Pyelonephritis
15 years and older: 250 to 333 mg orally every 6 hours OR 500 mg orally every 12 hours
- Maximum dose: 4 g per day
- Duration of therapy: 7 to 14 days
Use: Treatment of genitourinary tract infections caused by susceptible E coli, P mirabilis, and K pneumoniae
Usual Pediatric Dose for Bacterial Infection
American Academy of Pediatrics (AAP) Recommendations:
Children (Older than neonates):
- Mild to moderate infection: 25 to 50 mg/kg orally in 2 to 4 doses
- Severe infection: 75 to 100 mg/kg orally in 3 to 4 doses
Comment: Current guidelines should be consulted for additional information.
Usual Pediatric Dose for Bacterial Endocarditis Prophylaxis
AHA and IDSA Recommendations: 50 mg/kg orally as a single dose 30 to 60 minutes before the procedure
Use: Prevention of infective endocarditis in patients allergic to penicillins/ampicillins undergoing a dental procedure (except in immediate hypersensitivity)
Renal Dose Adjustments
15 years and older:
CrCl 30 to 59 mL/min: The maximum daily dose is 1 g.
CrCl 15 to 29 mL/min: 250 mg orally every 8 to 12 hours
CrCl 5 to 14 mL/min: 250 mg orally every 24 hours
CrCl 1 to 4 mL/min: 250 mg orally every 48 to 60 hours
Liver Dose Adjustments
Data not available
Precautions
Safety and efficacy have not been established in patients younger than 1 years.
Consult WARNINGS section for additional precautions.
Dialysis
Data not available
Other Comments
Administration advice:
- This drug may be taken with or without food.
- Tablets and capsules should be taken with a full glass of water.
Storage requirements:
- Capsules: Protect from light and moisture.
- Oral suspension: Store in the refrigerator (2 to 8C) when not in use.
General:
- Limitation of use: This drug should not be used to treat patients with severe systemic infections during the acute phase.
- This drug may be preferred to other antibiotics in pediatric patients due to increased tolerability and palatability.
Monitoring:
- Hematologic: Prothrombin time (especially in patients at risk of prolonged prothrombin time)
- Renal: Renal function (especially in patients with renal dysfunction)
Patient advice:
- Patients should be told to report any unusual or severe side effects.
- Patients should be instructed to report signs/symptoms of Clostridium difficile (e.g., watery/bloody stools, stomach cramps, fever), for up to 2 months after stopping treatment.
- Patients should be directed to take the full course of treatment, even if they feel better.
- Patients receiving the oral suspension/syrup formulations should be told to discard any remaining drug at the end of the duration of therapy.
Frequently asked questions
- What are the best antibiotics for a tooth infection?
- What is the best antibiotic to treat strep throat?
- Can Cephalexin treat an abscess in the mouth or gum infection?
- If people are allergic to amoxicillin can they take cephalexin?
- Can you take cephalexin for a spider bite?
- Can you take antibiotics while pregnant?
- Cephalexin - is this a drug that can be abused by teens?