Antipyretic analgesics

Publisher This chapter discusses the several antipyretic analgesics and their adverse effects. Salicylates carry an excess risk of 0.4 per million users (relative risk 2.6). In absolute terms, the risk is small. However, the excess risk may accumulate over time in chronic users. Aspirin can cause dose-related focal hepatic necrosis that is usually asymptomatic or anicteric. Blood salicylate concentrations above 1.8 mmol/l (250 pg/ml) are usually required for the hepatotoxic effect. Children with juvenile rheumatoid arthritis or acute rheumatic fever and adults with active rheumatoid arthritis or systemic lupus erythematosus appear to be especially susceptible to salicylate-induced liver injury. The anthranilic acid derivatives include glafenine, antrafenine, floctafenine, and the fenamates (mefenamic, flufenamic, etofenamic, and meclofenamic acids). Both glafenine and the fenamates cause frequent adverse effects, most of which are gastrointestinal. These adverse effects are usually attributed to prostaglandin inhibition.