Dear Don,

Keflex got b.i.d. approval  for skin and soft tissue indications about 20 years ago. I remember that because Duracef had come out with daily dosing, so the Lilly folks (I think Lilly makes Keflex?) did studies on Keflex for bid dosing.

I use 40 mg/kg, which is the longstanding dose recommendation.

For me, "skin and soft tissue" would include pharyngitis, cellulitis, and wound prophylaxis. Way easier to use 1 g bid then 500mg qid for these things.
In adults with cellulitis (along with Septra DS), I often start 1g bid x 2 days then 500 bid x 5 days. 

For me, "skin and soft tissue" would NOT include bone (after IV Ancef given for an open fracture) or UTI - in which case I use tid or qid dosing.

Just my 2 cents.
take good care,

Bruce Nayowith MD
Great Barrington MA

Date:    Sat, 25 Jul 2009 09:15:46 -0700
From:    don zweig <[log in to unmask]>
Subject: doses of abx (uti)

Whenever i look up Keflex dosing for kids it says 25-100mg/kg divided  
qid.  What kind of guideline is this; there is a 4 fold delta.  I was  
looking at the U of Cinci guidelines for treating first uti in kids  
and it says 25-100mg/kg.  This is not helpful.

What dose do you use?  does it need to be qid or like penicillin for  
strept can it be bid?


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