VARIABILITY IN SUSCEPTIBILITY - HOW BIG, HOW OFTEN FOR WHAT RESPONSESTO WHAT AGENTS

This paper surveys some recent available observations in humans on int erindividual variability in exposure-related parameters, pharmacokinet ics, and pharmacodynamics. Overall, I think two inferences are warrant ed. First, the drug and epidemiological literatures do contain informa tion that can shed new light on the extent of variability in the doses associated with different non-cancer responses. These data are waitin g to be systematically extracted and analyzed. Second, I think it is l ikely that with more systematic measurement and analysis of interindiv idual variability we are likely to find that there are systematic tend encies for some kinds of responses to some categories of agents to occ ur at more variable exposures/doses than others. If we gather and anal yze additional data of this type, we may be able to recommend adaptive modifications to the ten-fold safety factor tuned to these difference s.