Cephalexin Dosage

Usual Adult Dose for Bacterial Endocarditis Prophylaxis

2 g orally as a single dose one hour before the procedure

Usual Adult Dose for Cystitis

250 mg orally every 6 hours or 500 mg orally every 12 hours for 7 to 14 days

Usual Adult Dose for Otitis Media

500 mg orally every 6 hours for 10 to 14 days

Usual Adult Dose for Pharyngitis

250 mg orally every 6 hours or 500 mg orally every 12 hours

Usual Adult Dose for Skin or Soft Tissue Infection

250 mg orally every 6 hours or 500 mg orally every 12 hours

Usual Adult Dose for Osteomyelitis

500 mg orally every 6 hours
Therapy should be continued for approximately 4 to 6 weeks, depending on the nature and severity of the infection. Chronic osteomyelitis may require an additional one to two months of antibiotic therapy and may benefit from surgical debridement.

Usual Adult Dose for Prostatitis

500 mg orally every 6 hours for 14 days

Usual Adult Dose for Pyelonephritis

500 mg orally every 6 hours for 14 days

Usual Adult Dose for Upper Respiratory Tract Infection

250 to 500 mg orally every 6 hours for 7 to 10 days

Usual Adult Dose for Bacterial Infection

250 to 500 mg orally every 6 hours
Therapy should be continued for approximately 7 to 21 days, depending on the nature and severity of the infection.

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 Bacterial Endocarditis Prophylaxis

As an alternative in penicillin-allergic patients (non-anaphylactoid type): 50 mg/kg (maximum 2 g) orally once, 1 hour before procedure

Renal Dose Adjustments

CrCl 10 to 40 mL/min: The usual dose should be administered every 8 to 12 hours.
CrCl 9 mL/min or less: The usual dose should be administered every 12 to 24 hours.

Liver Dose Adjustments

Data not available

Dose Adjustments

Infections that are more severe or caused by less susceptible organisms may require dosages up to 4 g per day in divided doses.

Precautions

Serious and occasionally fatal hypersensitivity reactions have been reported with antibiotics. The drug should be discontinued immediately at the first appearance of a skin rash or other signs of hypersensitivity. Severe, acute hypersensitivity reactions may require treatment with epinephrine and other resuscitative measures including oxygen, intravenous fluids, antihistamines, corticosteroids, cardiovascular support and airway management as clinically indicated.

Clostridium difficile associated diarrhea (CDAD) has been reported with almost all antibiotics and may potentially be life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea following cephalosporin therapy. Mild cases generally improve with discontinuation of the drug, while severe cases may require supportive therapy and treatment with an antimicrobial agent effective against C difficile. Hypertoxin producing strains of C difficile cause increased morbidity and mortality; these infections can be resistant to antimicrobial treatment and may necessitate colectomy.

Patients with phenylketonuria should be aware that some formulations (e.g., dispersible tablets) contain phenylalanine.

Caution is recommended in patients with impaired renal function. Some cephalosporins have been associated with seizures in renally impaired patients with elevated serum concentrations. The drug should be discontinued if seizures occur.

Parenteral cephalosporins should be considered in patients requiring daily cephalexin doses greater than 4 grams.

To reduce the risk of development of drug resistant organisms, antibiotics should only be used to treat or prevent proven or suspected infections caused by bacteria. Culture and susceptibility information should be considered when selecting treatment or, if no data are available, local epidemiology and susceptibility patterns may be considered when selecting empiric therapy. Patients should be advised to avoid missing doses and to complete the entire course of therapy.

Dialysis

Cephalexin is moderately dialyzable (20% to 50%).

Other Comments

In the treatment of beta-hemolytic streptococcal infections, a therapeutic dosage should be administered for at least 10 days.

The adult dosage should be 1 to 4 g per day in divided doses. When using the 333 mg or 750 mg capsules, the total daily dosage of cephalexin should not fall outside this range.

The dispersible tablets for oral suspension should be mixed with 2 teaspoonfuls of water, the patient should drink the entire mixture, then a small amount of water should be used to rinse the container, and the patient should drink this also.