Mechanisms of action and clinical applications of cytotoxic drugs in rheumatic disorders.

Failure to suppress disease activity in certain rheumatic disorders such as systemic lupus, polyarteritis nodosa, or Wegener's granulomatosis may significantly heighten the probability of a fatal outcome. In other rheumatic disorders (for example, rheumatoid or psoriatic arthritis) the disease left unchecked may indeed be severely crippling but rarely is it fatal. Thus the decision on whether to add a cytotoxic drug often evolves into a benefit-to-risk analysis, a decision in which the patient must also be intimately involved. There are two few well-controlled studies of the use of cytotoxic agents to make dogmatic statements regarding their use in the treatment of rheumatic disorders. Nevertheless, a review of the literature, some of which has been cited above, does permit one to make some reasoned judgments in choosing a drug for a particular disease (Table 2).