What is the typical dosage of Cephalexin for treating bacterial infections?

Typical Dosage of Cephalexin for Bacterial Infections

The standard adult dosage of cephalexin for treating bacterial infections is 250-500 mg every 6 hours or 500 mg every 12 hours, with a total daily dose ranging from 1-4 grams depending on infection severity, while pediatric dosing is typically 25-50 mg/kg/day divided into 4 doses. 1

Adult Dosing

Uncomplicated Infections

• For mild to moderate infections such as uncomplicated skin and soft tissue infections, the typical adult dose is 250 mg every 6 hours 1
• For streptococcal pharyngitis and uncomplicated skin and skin structure infections, 500 mg every 12 hours is an effective regimen 1
• For skin abrasions with signs of infection, 500 mg three times daily is recommended by the Infectious Diseases Society of America 2

More Severe Infections

• For more severe infections, the dose may be increased to 500 mg four times daily 3, 2
• If daily doses greater than 4 g are required, parenteral cephalosporins should be considered instead 1
• For complicated skin and soft tissue infections, higher doses within the 1-4 g daily range may be necessary 1

Pediatric Dosing

• The standard recommended daily dosage for pediatric patients is 25-50 mg/kg divided into equal doses throughout the day 1
• For streptococcal pharyngitis in children over 1 year and skin/skin structure infections, the total daily dose may be divided and administered every 12 hours 1
• For otitis media, higher doses of 75-100 mg/kg/day in 4 divided doses are required 1
• In severe infections, pediatric dosages may be doubled 1
• For infants 29-60 days old with urinary tract infections, cephalexin can be dosed at 50-100 mg/kg per day in 4 doses 3

Duration of Therapy

• For typical skin and soft tissue infections, treatment duration is usually 7 days, depending on clinical response 2
• For β-hemolytic streptococcal infections, cephalexin should be administered for at least 10 days 1
• For urinary tract infections, treatment should be continued for 7-14 days 1

Dosing Frequency Considerations

• Recent evidence suggests that twice-daily dosing (500 mg BID) may be as effective as four-times-daily dosing for uncomplicated urinary tract infections, which could improve patient adherence 4
• For chronic urinary tract infections, studies have shown that 1 g twice daily for 10 days can be as effective as when the same total dose is given 4 times a day 5

Special Considerations

• Patients with renal impairment (creatinine clearance less than 30 ml/min) require a reduction in cephalexin dosage proportional to the reduced kidney function 6
• Cephalexin is not effective against MRSA; if MRSA is suspected or confirmed, alternative agents should be considered 2
• Patients with a history of immediate hypersensitivity to penicillin should use cephalexin with caution due to potential cross-reactivity 2

Administration Notes

• Cephalexin is administered orally and is available in capsule form and as oral suspension 1
• The oral suspension must be prepared at the time of dispensing by adding the specified amount of water to the powder 1
• After mixing, the suspension should be stored in the refrigerator and may be kept for 14 days without significant loss of potency 1

Cephalexin has good activity against common pathogens causing skin, respiratory, and urinary tract infections, including Staphylococcus aureus (non-MRSA) and Streptococcus species 2, making it an appropriate choice for many common bacterial infections when dosed correctly.