Drug interaction in the field of analgesic drugs.

The evidence for believing that mixtures of aspirin, phenacetin, and caffeine provide advantages over the individual components of these mixtures is reviewed, and doubt expressed as to the rationale for the use of these mixtures in ordinary medical practice. The syndrome of ;analgesic nephropathy' is also reviewed, and on the basis of experiments in healthy volunteers it is suggested that individual ingredients of analgesic mixtures be scrutinized more carefully in an attempt to track down the agents responsible for toxic effects.The use of phenothiazine compounds, alone or in mixture with narcotics, is reviewed, and the opinion expressed that methotrimeprazine has special analgesic attributes.The narcotic antagonists represent an extremely interesting group of drugs which possess analgesic activity as well as the ability to antagonize certain effects of morphine and other narcotic agents. The patterns of respiratory effect, psychotomimesis, and abstinence phenomena seen with these antagonists illustrate the possibility of dissociating certain effects usually assumed to be linked inseparably in drugs possessing the analgesic power of morphine.