Table 2.

Classification of adverse drug reactions.

Type A	Type B
Predictable	Unpredictable
Common	Infrequent
Often mild, self-limited	Often severe
Based on the drug's known pharmacology	Based on genetic or other factors
Dose-dependent	No clear relationship to drug dose
Acts on drug's site of action or similar site	Unrelated to the site of drug action

Modified from Rieder (2012).