Type B adverse drug reaction

Sometimes called “off-target” or idiosyncratic effects. These occur due to effects on targets that are not the intended drug target, and they may be caused by reactive metabolites. They are often immunological in nature, and as such, are often not dose-dependent. They usually only occur in a relatively small proportion of patients and they are more difficult to predict. Many Type B adverse drug reactions (ADRs) may only be observed during post-marketing surveillance.