Floctafenine: a valid alternative in patients with adverse reactions to nonsteroidal anti-inflammatory drugs

Choosing an alternative anti-inflammatory agent for a patient who has suffered adverse reactions to nonsteroidal anti-inflammatory drugs is a common problem in clinical practice, and it is complicated by the possibility of non-immunologic cross reactivity among the various members of this drug class.

We performed a retrospective study based on oral challenge results in 150 patients with histories of adverse reactions to one or more nonsteroidal anti-inflammatory drugs. The alternative drugs tested included floctafenine, an analgesic of the fenamic acid group, nimesulide, or paracetamol (acetaminophen).

One hundred fifty patients with histories of adverse reactions to nonsteroidal anti-inflammatory drugs received oral challenges with floctafenine; 101 were also challenged with nimesulide and paracetamol. The oral challenges were administered under single-blinded conditions. One-fourth of the therapeutic dose (floctafenine, 200 mg; nimesulide, 100 mg; and paracetamol, 500 mg) was administered initially; the remaining 3/4 was given one hour later if no symptoms had developed with the initial administration. In patients with histories of rhinitis and/or bronchial asthma unrelated to drug use and those whose adverse reactions had included bronchospastic or rhinitic symptoms, the FEV1 was measured. The response to the challenge was considered positive if any of the following symptoms developed: erythema, pruritus accompanied by erythema, urticaria/ angioedema, rhinorrhea, nasal obstruction, sneezing, dyspnea or cough associated with a decrease of at least 20% in the FEV1, hypotension.

Floctafenine challenges were positive in 13/150 patients (8.7%). Nimesulide and paracetamol provoked reactions in 9/101 patients (8.9%). All positive reactions occurred within 24 hours of the challenge. None of the patients reacted to more than one of the drugs tested.

Our findings confirm those of other investigators regarding the use of nimesulide and paracetamol in patients who do not tolerate aspirin or other nonsteroidal anti-inflammatory drugs, although the percentage of reactions to nimesulide observed in the present study is somewhat higher than that reported by some other groups. The study also indicates that floctafenine, a relatively weak cyclooxygenase inhibitor, can be a valid alternative for many patients who react adversely to other nonsteroidal anti-inflammatory drugs.