375 Non-steroidal Anti-inflammatory Drugs Hypersensitivity: Patterns of Reaction

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently groups of medications involved in hypersensitivity drug reactions. The aim of this study is to describe a group of patients with suspected hypersensitivity reactions to non-steroidal anti-inflammatory drugs. METHODS: A retrospective study of patients with a suspected history of hypersensitivity to NSAIDs, between years 2005 to 2010, was done. The drugs involved, the clinical features and interval between drug intake and clinical manifestation were studied. Drug provocation tests were carried out in some cases to confirm the diagnosis and in others to provide a safe therapeutic alternative drug. RESULTS: A total of 310 patients considered to have had hypersensitivity reactions to NSAIDs were analyzed (mean age = 39 years old; females = 247). Immediate reactions were reported in 209 subjects. Non-selective responders were 214. The most important suspected drugs were pyrazolones (228), paracetamol (144), acetic acid derivatives (122) and acetyl salycilic acid (120). Pyrazolones were the most important suspected drugs for the selective responders. The most frequent clinical manifestations were angioedema (162), airway involvement (96) and urticaria (66). Isolated angioedema was seen in 79 patients. Atopy was reported in 138 (44.5%) patients and chronic urticaria in 26 (8.3%). Family history of drug hypersentivity was reported by 37 patients. Drug provocation tests (DPT) for diagnosis were performed with paracetamol in 37 subjects (2 positive), and pyrazolone in one subject (negative). DPT were also performed with selective COX-2 inhibitors (31 tests) and benzydamine (45 tests) to assess their safety as therapeutic alternative drugs for those non-selective responders and for those who had a suspected history of reactions to paracetamol, respectively. Positive results were observed in 3 patients tested with COX-2 inhibitors and in one patient tested with benzydamine. CONCLUSIONS: NSAIDs hypersensitivity was more prevalent in females and immediate reactions were more common than non-immediate ones. A great number of subjects were non-selective responders. Pyrazolones were the most commonly suspected culprit drugs. DPT is important not just for diagnosis but also to provide safe therapeutic options.