Cephalexin Dosage

Medically reviewed by Drugs.com. Last updated on Aug 2, 2023.

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

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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