Models for clinical assessment of oral analgesics

Renewed interest in analgesic models has been stimulated by the development of several new nonsteroidal anti-inflammatory drugs. Many of these new analgesic agents appear to have higher peak effects and longer durations of action than acetylsalicylic acid. Sensitive models are necessary to determine the dose-effect relationships and relative analgesic efficacies of these new agents. The basic principles of clinical methods--double-blinding, identical appearance of study medications, and random allocation of treatments to subjects--must be adhered to. However, additional precautions must also be taken. The choice of pain models and further subdivision of subjects within a pain model are critical for assay sensitivity. The dental pain model has become popular because the surgical procedures can be easily categorized, and each subpopulation is relatively homogeneous. There now is a body of data that substantiates the assay sensitivity of the dental pain model, and its usefulness in predicting the general analgesic efficacy of nonsteroidal anti-inflammatory drugs. Other pain models, including general postsurgical, orthopedic postsurgical, and postpartum pain, also have demonstrated adequate assay sensitivity to determine the relative efficacy of new nonsteroidal anti-inflammatory drugs.