Table 2.

How dose related, time related, and susceptibility related classifications of adverse drug reactions fulfil criteria for satisfactory classification

	Classification
Criterion	Dose related	Time related	Susceptibility related
Allows classification on basis of clinical features	No; dose dependency is not always clear from clinical observations and dose ranging studies are not always available	Yes; the time course of a reaction can be directly observed in individual cases or populations	Sometimes, depending on type of susceptibility
Give insight into mechanism of reaction	No; only implies the range of doses at which it occurs	Yes; different mechanisms have different time courses	Yes; mechanism and susceptibility are often linked
Avoids assigning a reaction to more than one category	No	Yes	No; an adverse drug reaction may be associated with multiple susceptibility factors
Suggests how to monitor adverse reactions	Yes	Yes	Yes
Suggests population strategies for pharmacovigilance	Yes	Yes; also tells the patient when to be alert for an adverse reaction	Yes (can identify patients at high risk or low risk)
Helps in making decisions on treatment or avoiding adverse reactions	Only some types	Yes	Only some types
Guides drug development and regulation	Yes; can help in defining the therapeutic dosage range	Yes; suggests strategies for monitoring during drug development and after marketing	Yes; defines subgroups at high risk or low risk