Pharmacological criteria for risk-benefit evaluation of NSAIDs.

Evaluation of new non-steroidal anti-inflammatory drugs (NSAIDs) must compare efficacy and toxicity with existing compounds. Real progress involves maintaining effectiveness while decreasing toxicity. It is relatively easy to assess the effects of NSAIDs in animal models, and to determine gastrointestinal toxicity. However, although the ratio of active and toxic doses in animals can be extrapolated to man, the approach is limited and the NSAID needs to be assessed in a clinical setting as early as possible. In France, a national survey system has reported a wide range of adverse effects related to NSAIDs and shown important differences between compounds. Overdosage may be one of the factors responsible for toxicity, therefore pharmacokinetic evaluation is useful. In some disease states e.g. rheumatoid arthritis, there is a higher possibility of saturation pharmacokinetics with some drugs. Other pharmacokinetic parameters of interest are half-life, functions limiting activity, and hepatotoxicity. Furthermore, different pharmacokinetic parameters are required for different forms of disease. In acute states, the NSAID should have a short half-life and low protein binding and vice versa in chronic states. An important goal is to develop more selective NSAIDs regarding mechanisms of action or distribution into diseased tissues.