Analgesics hypersensitivity reactions

Type B effects are not related to the pharmacological properties of these drugs. Serious side effects may occur. Allergic skin and liver reactions to aspirin and paracetamol have been reported with risk of fibrosis, particularly in the retroperitoneal region for methysergide and hypersensitivity reactions with NSAID and pure analgesics. 

Aspirin is the non-steroidal anti-inflammatory (NSAID) analgesic most commonly involved in adverse hypersensitivity reactions. With plasma concentrations over 350 pg mL-1, such as occur with overdose, aspirin directly stimulates the respiratoty centre, resulting in marked hyperventilation. Overdose is also associated with metabolic acidosis, particularly in infants and children, circulatory collapse and renal impairment. 

Although zomepirac is a pyrrole-acetic acid compound closely related to tohnetin, it was originally claimed to be a new tjrpe of analgesic drug. Its history is not unlike that of benoxaprofen. In 1982, because of the severity and frequency of hypersensitivity reactions, it was withdrawn voluntarily by the manufacturers worldwide on a temporary basis (1). It has not been relaunched. 

Aspirin is known to cause serious reactions in certain patients with asthma (Cooke 1919). The patients can also have rhinorrhea and nasal polyps that may precede the bronchoconstrictor type of intolerance to aspirin for months or years. This triad of symptoms is common in middle-aged women. The aspirin-sensitive patients often show intolerance to other analgesics (Smith 1971). Speer (1958) reported that color additives can precipitate asthma. Aspirin-sensitive patients with asthma also cross-react to tartrazine in 8%-15% of the cases (Chafee and Setti-PANE 1967 Samter and Beers 1967 Hosen 1972 Settipane and Pudupakkam 1975 Delaney 1976) and to various benzoates (Juhlin et al. 1972 Rosenhall and Zetterstrom 1973). Hypersensitivity to food colorants, preservatives, and analgesics was studied in 504 patients with asthma and rhinitis by Rosenhall (1977). Hypersensitivity to at least one of the substances was found in 106 patients. In 33 patients sensitive to tartrazine 42% were intolerant to aspirin and 39% to sodium benzoate. Rosenhall also tested his patients with other azo dyes such as Sunset Yellow and New Coccine as well as the non-azo dyes carmine and patent blue. The method of examination and reproducibility of the results were studied in detail. Dietary treatment was found to be effective in some patients in preventing exacerbations of the disease but on the whole had no influence on the course of the disease or the need for medication. 

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