Originally posted by oxford mushroom:
The TS received an antibiotic that combines two drugs,
amoxicillin (a type of penicillin) and clavulanic acid, a
beta-lactamase inhibitor. The latter inhibits the breakdown of
amoxicillin by some bacteria that are resistant through the
production of lactamase, an enzyme that breaks down the
antibiotic.
This combination is effective against a wide range of bacteria and
has been used for more than a decade.
As for the pharmacokinetics, amoxicillin has greater oral
bioavailability compared to PenV and ampicillin. This is what the
FDA says:
"Approximately 74-92% of a single dose of amoxicillin is absorbed
while approximately 60-70% of an oral penicillin V dose and 30-55%
of an oral ampicillin dose are absorbed. Peak serum amoxicillin
concentrations (Cmax) are reached 1-2 hours after an oral dose of
the capsules, film-coated tablets, chewable tablets, or oral
suspension [b]in fasting and non-fasting adults.
Non-linearity in absorption of amoxicillin has been reported when
increasing doses of 250mg, 500mg, and 1000mg of amoxicillin were
administered to fasting adults. A significant reduction in the
percentage of the dose absorbed was observed for the 1000mg dose
(5)."
(http://www.fda.gov/cder/drugprepare/amox-anthrax.htm)
The clavulanic acid component is shown not to interfere with the
absorption of amoxicillin and vice versa. However, oral absorption
of clavulanic acid can be highly variable (http://cat.inist.fr/?aModele=afficheN&cpsidt=14518475).
The bio-availability of amoxicillin/clavulanic acid combination has
been shown to be unaffected by food. Here's an abstract of a study
done to address this very question:
"Augmentin, the novel antibiotic formulation containing the
ß-lactamase inhibitor, clavulanic acid, and the -lactam antibiotic,
amoxycillin, has been the subject of two studies reported here on
bioavailability and tolerance.
Eighteen subjects took part in a two-part crossover study to
compare the bioavailability when taken fasting and with food.
The bioavailability was shown to be unimpaired when taken
with food.
Forty-five healthy subjects took part in a series of crossover
studies to compare the tolerance of Augmentin taken fasting and
with food. Augmentin was also compared with cephalexin under the
same conditions. The gastro-intestinal side effects
reported in these volunteer studies, which are rare in clinical
practice, were reduced when Augmentin was taken with
food. "
(Staniforth DH, Lillystone RJ, Jackson D. Effect of food on the
bioavailability and tolerance of clavulanic acid/amoxycillin
combination. Journal of Antimicrobial Chemotherapy (1982) 10,
131-139)
In other words, this antibiotic combination can be taken either
before or after meals. It does not matter to the bioavailability.
However, because some people get tummy upset as a side effect of
this antibiotic, the recommendation is to take it with food to
reduce that side effect.
There are many reasons why the antibiotic did not work as well as
it did. First, the bacteria may not be sensitive to the antibiotic.
Perhaps the wound was infected with a bacteria that is not
sensitive to this antibiotic or surgical debridement is needed. The
medication the TS received sounds like a generic rather than
Augmentin (the original 'branded' drug). Depending on where it was
manufactured, the formulation and bioavailability may differ.
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