It has been largely assumed, that because 29 tablets of the painkiller co-proxamol were missing from the blister packets in Dr Kelly's pockets, that he took all 29.
It was known by those close to them he had a strong aversion to taking tablets, but even if that were so, he could not have ingested all 29 tablets, because he regurgitated a large part of his stomach contents. The forensic biologist reported a large amount of vomit on the ground and all that remained in his stomach was residue equivalent to a fifth of one tablet. So the amount ingested did not represent much of an overdose.
It is important to note that gauging how much of a particular drug a person ingested is not an exact science.
One of Milroy's colleagues at the University of Sheffield, forensic toxicologist Professor Robert Forrest, has helpfully pointed out that concentrations of a drug in the blood increase markedly over time - as much as tenfold.
Since Dr Allan did not analyse Dr Kelly's blood for well over 24 hours, the concentration of co-proxamol components may have increased up to tenfold.
So while Dr Allan judged the amount of co-proxamol in the blood to be only a third of what is normally a fatal amount, this could mean that the actual amount ingested by Dr Kelly 24 hours or so earlier, was far less than a third of a fatal amount - possibly as little as a thirtieth.
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