Anaphylactoid reactions to tolmetin after interrupted dosage

Seven patients had anaphylactoid reactions after ingesting tolmetin sodium. In each case the reaction followed readministration of the drug after an interrupted period of at least three days and within 90 minutes of taking a single 400-mg capsule. None of the patients had had prior anaphylaxis and none were judged atopic. Skin tests to an extract of the drug (0.02 mg) were uniformly negative, whereas a higher concentration produced a nonspecific irritant reaction. In vitro tests in one patient for IgE antibodies to tolmetin and for complement activation were negative.