Recommended Keflex Dosing for Continued Cellulitis Treatment
Continue Keflex 500 mg every 6 hours for an additional 5 days only if the cellulitis has not completely resolved; otherwise, discontinue antibiotics now. 1
Treatment Duration Decision Algorithm
The most recent IDSA guidelines establish a clear 5-day treatment endpoint for cellulitis when clinical improvement has occurred 1. Since you completed 5 days of Keflex with "most" of the cellulitis cleared, the critical decision point is:
If clinical improvement has occurred (reduced erythema, decreased warmth, less pain, no spreading):
- Stop antibiotics now - no additional Keflex is needed 1, 2
- The traditional 10-14 day courses are outdated and no longer recommended 1
If the infection has NOT improved within the initial 5-day period:
- Continue Keflex 500 mg every 6 hours for an additional 5 days 1, 3
- Reassess in 48 hours for treatment response 1
Dosing Specifications
The FDA-approved dosing for skin and soft tissue infections is 500 mg every 12 hours OR 250 mg every 6 hours 3. However, for more severe infections or partially responsive cases, 500 mg every 6 hours (2 grams daily total) is appropriate and within the approved 1-4 gram daily range 3.
Critical Reassessment Points
You must evaluate for treatment failure indicators:
- Spreading erythema beyond the original margins 1
- Development of systemic signs (fever >38.5°C, tachycardia >110 bpm, confusion) 4
- Severe pain out of proportion to examination findings (suggests necrotizing infection) 1
- New purulent drainage or fluctuance (suggests abscess formation requiring drainage) 1
If any of these are present, do NOT simply continue Keflex - switch to MRSA-active therapy (vancomycin IV or clindamycin 300-450 mg every 6 hours orally) or obtain surgical consultation 1.
Essential Adjunctive Measures
These non-antibiotic interventions are as important as the medication:
- Elevate the affected forearm above heart level for at least 30 minutes three times daily to promote gravity drainage 1, 2
- Examine for entry portals (cuts, abrasions, tinea) and treat any identified 1, 5
- Apply daily emollients to prevent skin cracking 5
Evidence Quality Note
The 5-day treatment duration recommendation comes from high-quality randomized controlled trial evidence published in 2025 guidelines 1, superseding older 10-14 day regimens. Beta-lactam monotherapy (like Keflex) succeeds in 96% of typical cellulitis cases 1, confirming that extending treatment beyond 5 days when improvement has occurred provides no additional benefit and only increases antibiotic resistance risk.
Common Pitfall to Avoid
Do not reflexively prescribe another 5-10 days of antibiotics simply because "some" cellulitis remains 1. Residual erythema and induration can persist for weeks after bacterial eradication and do not require continued antibiotics if the infection is no longer progressing 1. The key distinction is improvement versus progression - if the cellulitis is better than it was 2-3 days ago, stop antibiotics now 1, 2.