ABSTRACT
The administration of a medicine to patients would produce two different responses, beneficial therapeutic effects (efficacy) and adverse drug reactions (ADRs, or toxicity). According to the information provided by Marsh and McLeod (2006), 7% of patients were affected by ADRs in the UK in 1994, whereas this number is estimated as 2,216,000 hospital patients, leading to approximately 106,000 patient deaths and making ADR fatalities the fourth to sixth leading cause of death in the US in the same year. There is considerable variability in the pattern of drug response among different individuals (Fig. 11.1), which can be categorized into four types: (1) There is a benefit and also toxicity, (2) there is a benefit, but no toxicity, (3) there is no benefit, but there is toxicity, and (4) there is neither benefit nor toxicity.
