Is there a script for three times daily (TID) dosing of cephalexin?

Cephalexin TID Dosing for Skin and Soft Tissue Infections

Yes, cephalexin 500 mg three times daily (TID) is a well-established and guideline-supported dosing regimen for skin and soft tissue infections in adults. 1, 2

Standard TID Dosing Regimen

• The Infectious Diseases Society of America (IDSA) explicitly recommends cephalexin 500 mg TID as a standard oral dosing option for skin and soft tissue infections caused by methicillin-susceptible staphylococci and streptococci. 1, 2

• The FDA label confirms that for streptococcal pharyngitis and skin/skin structure infections, 500 mg may be administered every 12 hours, but the standard adult dosage is 250 mg every 6 hours (QID), with flexibility for TID dosing based on clinical guidelines. 3

• For prosthetic joint infections requiring chronic oral suppression, IDSA guidelines specifically list cephalexin 500 mg PO TID or QID as preferred treatment for oxacillin-susceptible staphylococci. 1

Evidence Supporting TID Dosing

• Multiple clinical trials demonstrate that less frequent dosing (BID or TID) is equally effective as QID dosing for staphylococcal skin infections. A randomized controlled trial showed cephalexin administered twice daily was equally effective to four times daily dosing, with both regimens achieving >97% efficacy. 4

• Another comparative study confirmed that cephalexin 500 mg TID for 7 days was as safe and effective as alternative regimens for uncomplicated skin infections. 5

• Pediatric pharmacokinetic modeling supports that TID dosing at 15-25 mg/kg achieves adequate drug exposure for MSSA with MIC 1-2 mg/L. 6

Clinical Considerations for TID Dosing

• TID dosing improves medication adherence compared to QID regimens while maintaining therapeutic efficacy. 7, 4

• The typical treatment duration is 7-10 days for uncomplicated skin and soft tissue infections. 1, 2

• Critical pitfall: Cephalexin has NO activity against MRSA. If MRSA is suspected or confirmed, alternative agents such as trimethoprim-sulfamethoxazole, doxycycline, or clindamycin must be used instead. 2, 8

• Cephalexin provides excellent coverage against methicillin-susceptible Staphylococcus aureus and Streptococcus species but misses Pasteurella multocida and most anaerobes. 1, 8

Dosing Algorithm

• For uncomplicated skin infections in adults: Start with cephalexin 500 mg TID for 7 days. 1, 2

• For more severe infections: Increase to 500 mg QID. 1, 3

• If no improvement within 5 days: Extend treatment duration and consider broadening coverage. 2

• Adjust dosing based on renal function, as cephalexin is renally cleared. 1