Some drugs may provoke allergic reactions in sensitive subjects. A real allergy to a drug should not be confused with the adverse or side-effects of the drug.
A drug allergy may be due to the active ingredient itself or to non-active ingredients (excipients). An excipient is added to your medicine for a variety of reasons. For example it may be used to add bulk to tablets (otherwise they could be too small to pick up). Preservatives (ingredients added to preserve the efficacy of the active compound and to confer a longer shelf-life) may also be responsible for an allergic reaction. This is known to be the case with the use of beta-adrenergic blocking agents.
Active substances whose allergenic potential is well known include:
- Antibiotics such as penicillin and its derivatives (your General Practitioner should be informed if you know you are sensitive to these drugs)
- Insulin
- Anti-tetanus and anti-diphtheria serums
- Aspirin and salicylate derivatives (that may sometimes be used as food preservatives).