A 57-year-old female patient treated with sulfasalazine (Salazopyrin, dose unknown) for gastrointes

Fråga: A 57-year-old female patient treated with sulfasalazine (Salazopyrin, dose unknown) for gastrointestinal problems developed hypersensitive reactions such as an irritating cough and nasal congestion. The patient has stopped taking Salazopyrin and feels that the symptoms are better. Are the patient´s symptoms a known side-effect of the drug? Is it possible to test the hypersensitivity?

Sammanfattning: "Irritating cough has been observed as a symptom of ""sulfasalazine lung"" and eosinophilic pleurisy, which seem to be rare. An increased frequency of side-effects has been seen with higher drug plasma concentrations (> 200 umol/l) and among patients with slow acetylation phenotypes."

Svar: Sulfasalazine lung is considered a well-known entity, generally defined as comprising infiltrates and giving rise to dyspnoea, cough, fever and chest pain (1). However, its occurrence is rare and less than 20 cases have been found in all the English-language literature. It usually appears about 1-6 months after the beginning of treatment and is generally reversible if the drug is withdrawn. Many of the patients described had earlier experienced hypersensitivity reactions to the drug (2).

Eosinophilic pleurisy was observed in a rheumatic man who had tolerated sulfasalazine well when it was first given but developed dyspnoea on exertion, pain in the lower thorax and bronchial irritation when it was restarted after an interval of a month. Both pleurisy and eosinophilia were found and ascribed to sulfasalazine allergy. The symptoms subsided within 1-4 weeks after the drug was withdrawn (cf 1).

The Swedish Adverse Drug Reactions Advisory Committee has received reports of 45 cases of respiratory side-effects, including 9 cases of pulmonary hypersensitive reaction, 13 cases of dyspnoea, 9 cases of cough and 7 cases of interstitial pneumonia. In FASS, respiratory side-effects such as fibrous alveolitis, eosinophilic lung infiltration, dyspnoea and cough are listed as rare adverse effects (3).

According to our Drugline documentation, there have been several well-performed studies which have found an increased frequency of side-effects with sulfasalazine concentrations more than 200 umol/l, daily doses of sulfasalazine higher than two grams and among patients with slow acetylation phenotypes (4). Provocation tests are not recommended because the allergic reactions can be serious and special care may be needed (5).