Intolerance to analgesics, particularly NSAIDs, is relatively common. It is thought that a variation in the metabolism of arachidonic acid is responsible for the intolerance. Symptoms include chronic rhinosinusitis with nasal polyps, asthma, gastrointestinal ulcers, angioedema, and urticaria.

Drug intolerance or drug sensitivity refers to an inability to tolerate the adverse effects of a medication, generally at therapeutic or subtherapeutic doses. Conversely, a patient is said to be "tolerating" a drug when they can tolerate its adverse effects. It is not to be confused with a drug allergy, which is a form of drug intolerance, but requires an immune-mediated component. It is also not to be confused with drug tolerance ("drug resistance," or tachyphylaxis) which refers to a "lack" of adverse effects even at higher than average doses. Some instances of drug intolerance are known to result from genetic variations in drug metabolism.