Table 1. Definitions.

Adverse drug reaction

An adverse drug is a response to a medicinal product, which is noxious and unintended. It is also known as a side effect. http://www.adrreports.eu/EN/glossary.html

Allergic drug reaction

Allergic drug reaction is an adverse drug reaction. It is an immunologically mediated reaction characterised by specificity, transferability by antibodies or lymphocytes, and recurrence on re-exposure. Vervloet D, Durham S (1998) Adverse reactions to drugs. BMJ 316: 1511–1514