Posted: Wed Nov 09, 2005 2:31 pm
Why measure plasma/serum concentrations anyway 
??
In my field, we do this to know more about what the body is doing with the drug, and which effect we obtain or might expect. For many drugs, there can be made a relation between plasma/serum concentration and effect (pharmaco dynamics). As Hans already said, plasma is easy to obtain and in generally more easy to analyze. So if there is a plasma concentration/clinical response effect, no reason to measure anything else. If there is no relationship, a good reason to measure something else (whole blood?). It is a good thing to see that pharmacodynamic studies are performed (and published) more frequently, also for older drugs.
regards Bert
??In my field, we do this to know more about what the body is doing with the drug, and which effect we obtain or might expect. For many drugs, there can be made a relation between plasma/serum concentration and effect (pharmaco dynamics). As Hans already said, plasma is easy to obtain and in generally more easy to analyze. So if there is a plasma concentration/clinical response effect, no reason to measure anything else. If there is no relationship, a good reason to measure something else (whole blood?). It is a good thing to see that pharmacodynamic studies are performed (and published) more frequently, also for older drugs.
regards Bert