Current Status of Issues Concerning the Safety of Over-the-Counter Analgesics and Nonsteroidal Anti-Inflammatory Drugs

Abstract

The safety of over-the-counter (OTC) analgesics has long been an issue and toxicity has led to the abandonment of a number of these drugs over the years. Acetanilide enjoyed great popularity for decades but it caused methaemoglobinaemia and haemolysis and has long since disappeared. Phenacetin lasted longer but it was mistakenly believed to be the primary cause of analgesic nephropathy and it too has virtually gone from the stage. There are important international and regional differences in the fashions of OTC analgesic use but these differences are not based on considerations of risk or benefit. Commercial interests also influence the availability and use of OTC analgesics and the overall result is a slowly changing scene in which the choice of agents and the rank order of their popularity varies in different regions over the years. The picture is further complicated by the use of analgesic combinations and the inclusion of these drugs in a wide range of remedies for common self-limiting conditions. Currently available OTC analgesics include aspirin and nonsteroidal anti-inflammatory drugs, paminophenol derivatives and the pyrazoles (Table 1). There are specific toxicological problems with all of these drugs and special problems arise from their uncontrolled use by virtually the whole population. The safety assessment of OTC analgesics must include the consequences of abuse and overdosage, their use by potentially vulnerable subjects such as the young, old, pregnant, and ill, the potential for adverse drug interactions and their pharmacokinetic properties (Table 2).