Aspirin has been available without prescription for many years. Although it is readily available, it is not free of adverse effects. Some patients have reactions to aspirin which may have presenting symptoms ranging from a skin reaction to angioedema and shock.

Hypersensitivity to aspirin is more frequent in patients with asthma. An analysis of spontaneous reports received by the Adverse Drug Reactions Advisory Committee indicates that, of the 47 cases of bronchospasm associated with ingestion of aspirin, 30 patients had a history of asthma. Furthermore, 16 of these 30 asthmatic individuals were known to be allergic to aspirin.

While health professionals will generally be aware of the risks associated with this class of drug, patients may not have this knowledge. Patients with aspirin hypersensitivity, particularly if they are asthmatic, should be aware that aspirin can trigger bronchospasm. Patients (and even some health care workers) may also not realise that other non-steroidal anti-inflammatory drugs (NSAIDs) are pharmacologically related to aspirin and can cause the same adverse reactions, especially in those who have had a previous allergy to aspirin.

A recent case highlights the issue of cross-reactivity:
A 49-year-old man with asthma and known hypersensitivity to aspirin was given a single indomethacin 100 mg suppository for back pain. This suppository was given while he was a hospital inpatient. He experienced acute respiratory distress with laboured breathing and hypercapnia. He lapsed into semi-consciousness and required urgent respiratory support involving intubation and assisted ventilation in intensive care. He subsequently recovered from the episode.

With the increased availability of NSAIDs over the counter, there is an increased potential for adverse reactions. While consumer product information may help to warn about cross-sensitivity, health professionals can also alert patients they know to be hypersensitive.

J. Dowden

Editor, Adverse Drug Reactions Advisory Committee, Canberra

A. Rohan

Secretary, Adverse Drug Reactions Advisory Committee, Canberra