Excipient-related adverse drug reactions : a clinical approach

Abstract

Formulations of the same active pharmaceutical ingredients (API) may contain a variety of inactive pharmaceutical ingredients (IPI) or excipients. Package inserts are important sources of information to clinicians and should provide details of both the API and the excipients in the pharmaceutical preparation. The Medicine Control Council’s published guidelines recommend the inclusion of excipients (qualitative) in the package insert, but this is not adequately enforced. Excipient-related adverse drug reactions (ADR) are common in clinical practice. Common adverse reactions caused by excipients are hyperactivity, bronchoconstriction, skin eruptions, angio-oedema and gastrointestinal symptoms. The management of patients with adverse drug reactions thus requires critical observation and judgement of the history and symptomatology of the patient in order to distinguish between an allergy and an intolerance in the clinical situation. It is essential to establish whether it is an API or excipientrelated ADR and the Cellular Antigen Stimulation Test (CAST) is recommended as a first line laboratory test to perform in order to come to the correct diagnosis. A clinical approach and guidelines are discussed and a clinical rating scale was compiled by the author that will aid the clinician in the diagnosis and management of excipient-related ADR.