Aspirin and acetaminophen as constituents of analgesic combinations.

Aspirin and acetaminophen are the mainstays of oral analgesic combinations. One group of combinations is composed of antipyretic-analgesics combined with each other. The superior efficacy of such combinations as compared with an optimal dose of one of the constituents remains to be proved, and there is little evidence that such combinations have less adverse-effect liability than a single agent. On the other hand, there is substantial evidence that combinations of an optimal dose of aspirin or acetaminophen with a narcotic (eg, codeine, hydrocodone, or oxycodone) produce an additive analgesic effect greater than that obtained by doubling the dose of either constituent administered alone. There is also some evidence that the adverse effects produced by such combinations are less than would be produced by an equianalgesic dose of a single constituent.