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Historic drug testing Vs contemporary drug testing
William Withering's digitalis soup
He discovered that an extract of foxgloves could be used to treat dropsy this extract contained the drug digitalis.
He made a CHANCE OBSERVATION a patient suffering from dropsy recovered after being treated by a traditional remedy containing foxgloves.
He started testing different versions of the remedy with different concentrations of digitalis.
He used TRIAL & ERROR too much digitalis poisoned his patient, whilst too little had no effect.
Contemporary drug testing
PRE-CLINICAL TESTING Animal studies and laboratory studies on isolated cells and tissue cultures assess
safety and determine whether the compound is effective against the target disease.
PHASE 1 A small group of (usually healthy) volunteers are told about the drug and
given doses. The trial confirms whether or not the compound is being absorbed, distributed, metabolised and excreted by the body in the way predicted
by the laboratory tests.
PHASE 2 Small groups of volunteer patients e.g. 100-300 people with the
disease, are treated to look at the drugs effectiveness.
Large group of patients, e.g. 1000-3000 people is selected and divided into two groups. One is given the compound being investigated; the second is given
a placebo (in some cases an existing treatment is used rather than a placebo). A placebo is an inactive substance that looks exactly like the drug but
doesn't do anything.
If the results show significant improvements in the patients receiving the treatment compared to those with the placebo or standard treatment then
compound being investigated is effective.
Often a DOUBLE BLIND TRIAL is used when neither the patients nor the doctors know who is having the compound under investigation and who is
having the placebo.