ANAPHYLACTIC REACTIONS ASSOCIATED WITH TRIMETHOPRIM

Background. Anaphylactic reactions to cotrimoxazole are often ascribed to the sulphamethoxazole component of this antibacterial drug. Object ive. To determine whether the trimethoprim component can be the cause of an anaphylactic reaction. Methods. An analysis was made of reports on anaphylaxis attributed to trimethoprim, as notified to the Drug Saf ety Unit of the Dutch Inspectorate for Health Care. Results. In the pe riod between September 1981 and November 1995, 13 such reports were re ceived. Nine were classified as probable anaphylaxis. Of these, the ca usal relationship between exposure to trimethoprim and anaphylaxis was classified as definite in three reports, and as probable in the other six. The remaining four reports were classified as possible anaphylax is. In one of these, the causal relationship was classified as definit e, and in three as probable. Conclusion. Although anaphylaxis due to t rimethoprim seems to be rare, it may be more common than previously th ought. Apparently, anaphylaxis to cotrimoxazole is not always caused b y sulphamethoxazole.