Cephalosporins. There are now four generations of cephalosporins. The third and fourth generation cephalosporin differences are fairly minor and we will treat those as a group. First generation cephalosporins and second generation cephalosporins do not cross the blood-brain barrier in adequate quantities to be able to use those for any CNS infections. So none of these would be recommended for treating a meningitis, for example. The first generation agents generally cover Gram positives including Staph aureus to about the same extent as the penicillinase resistant penicillins. So these are good drugs to use instead of the drugs like oxacillin.
The cephalosporins, as a group, may be useful in penicillin allergic patients but the general rule of thumb should be if they had an anaphylactoid reaction to penicillin, avoid cephalosporins if you can. If they have a rash with penicillin, there is probably about a 5% incidence of cross-reactivity but that’s not too much higher than the 3% background rate of rash that you are going to get anyway. So most clinicians would suggest that it is safe to use these provided you counsel the patient about stopping the drug and contacting you if a rash develops.
A major use for the first and second generation agents is in surgical prophylaxis, particularly the first generation agents. Gram negative spectrum with the first generation agents is quite spotty. We do not suggest that they be used for Gram negative infections. As I mentioned earlier, these are very useful and probably actually are the preferred drugs for treating non-methicillin resistant Staph aureus infections where a liquid is needed.
Cefazolin is Kefzol. You’ll notice I don’t have cephalothin or Keflin on this. Cephalothin had to be given every six hours. It caused a lot of IM pain. Cefazolin is given every eight hours. It causes less IM pain and really in most hospitals has replaced cephalothin and therefore that’s the only one I have listed here. So this would be the parenteral drug that usually would be used. Cephapirin or Cefadyl is another drug that is very much like cefazolin and has similar uses.
For the oral cephalosporins, actually these drugs may be quite useful in Staph aureus infections particularly as the liquids. Liquid Keflex of cephalexin. One of the products is bubble gum flavored. It’s quite well tolerated by children. It’s not terribly expensive so this may be a preferred product.
Antibiotics
Our experience here has been that cephalexin is the product we prefer in preadolescent children when we are trying to treat a Staph infection or we want to use an oral first generation cephalosporin. For adolescents and adults, we often would use cefadroxil. Cefadroxil does come in a liquid dosage form and is given less often so that should improve compliance. But our experience with trying to use cefadroxil in younger children, we found that we were having more treatment failures than when we had been using cephalexin so we switched back. So, in general, I would suggest the use of cephalexin or Keflex in younger children and in adolescents and adults use cefadroxil.
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