An Attempt at a Systematic Classification

O Causative drug action related to molecular pathology O Palliative drug action related to molecular physiology 

We have since come to understand the underlying genetic causes for many of the previously known differences in enzymatic activity, most prominently with regard to the P450 enzyme family, and these have been the subject of recent reviews [1, 2]. 

On the other hand, inter-individual differences in a drug s effects may also be observed in the presence of appropriate concentrations of the intended compound at the intended site of action, i.e., be due to differential pharmacodynamics. Here, two conceptually quite different conceptual scenarios may be distinguished that relate to the two principal mechanisms by which drags act etiology-specific and palliative. 

I Diseased physiology Dl-variant derailment of mechanism Ml. J Diseased physiology Dl-variant treatment with T2. 

An increasingly sophisticated and precise diagnosis of disease, arising from a deeper, more differentiated understanding of pathology at the molecular level, that will subdivide today s clinical diagnoses into molecular subtypes, will foster medi- 

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