What is the recommended dose of Keflex (Cephalexin) for dental prophylaxis?

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Keflex Dose for Dental Prophylaxis

For dental prophylaxis in patients with high-risk cardiac conditions, cephalexin (Keflex) is dosed at 2 grams orally as a single dose, taken 30-60 minutes before the dental procedure. 1

When Cephalexin Is Appropriate for Dental Prophylaxis

Cephalexin should only be used in penicillin-allergic patients who do NOT have a history of anaphylaxis, angioedema, or urticaria to penicillin. 1 If the patient has experienced these severe allergic reactions, cephalosporins must be avoided due to cross-reactivity, and clindamycin 600 mg orally should be used instead. 1

High-Risk Cardiac Conditions Requiring Prophylaxis

Prophylaxis is indicated only for patients with the following cardiac conditions undergoing dental procedures that manipulate gingival tissue, periapical region of teeth, or perforate oral mucosa: 1

  • Prosthetic cardiac valve or prosthetic material used for cardiac valve repair 1
  • Previous infective endocarditis 1
  • Unrepaired cyanotic congenital heart disease, including palliative shunts and conduits 1
  • Completely repaired congenital heart defect with prosthetic material or device during the first 6 months after the procedure 1
  • Repaired congenital heart disease with residual defects at or adjacent to prosthetic patch or device site 1

Dosing Regimens

Adults

  • Cephalexin: 2 grams orally, single dose, 30-60 minutes before procedure 1
  • Alternative if unable to take oral medication: Cefazolin 1 gram IV/IM or ceftriaxone 1 gram IV/IM within 30 minutes before procedure 1

Pediatric Patients

  • Cephalexin: 50 mg/kg orally (not to exceed adult dose), single dose, 30-60 minutes before procedure 1
  • Alternative if unable to take oral medication: Cefazolin or ceftriaxone 50 mg/kg IV/IM within 30 minutes before procedure 1

Procedures Requiring Prophylaxis

Prophylaxis is indicated for dental procedures involving: 1

  • Dental extractions 1
  • Periodontal procedures including surgery, scaling, root planing, and probing 1
  • Dental implant placement 1
  • Endodontic (root canal) instrumentation beyond the apex 1
  • Subgingival placement of antibiotic fibers 1
  • Initial placement of orthodontic bands 1
  • Prophylactic cleaning when bleeding is anticipated 1

Important Caveats

Cephalexin is NOT indicated for dental prophylaxis in patients with prosthetic joints. 2 The American Academy of Orthopaedic Surgeons and American Dental Association concluded that routine antibiotic prophylaxis before dental procedures in patients with prosthetic joints cannot be recommended, as bacteremia from daily activities poses greater risk than procedure-related bacteremia. 2

Standard prophylaxis is amoxicillin 2 grams orally, not cephalexin. 1 Cephalexin is reserved specifically for penicillin-allergic patients without severe hypersensitivity reactions. 1

Single-dose prophylaxis is the standard—prolonged courses are inappropriate. 3 A study found that while 87.3% of patients received indicated antibiotics, only 8.2% received them appropriately, with the primary error being prolonged duration when only a single preprocedure dose was needed. 3

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

2
Guideline

Antibiotic Prophylaxis for Dental Procedures in Patients with Prosthetic Hip

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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