Monitoring the effects of drug treatment to avoid pitfalls. Which drugs? Which tests? How often?

Given the power and risks of modern drugs, clinicians in primary care have come to regard monitoring as a routine part of clinical observation at every review consultation. It becomes so routine that we often forget we are monitoring. Experience leads to increased expectation of the unexpected! This chapter presents the main drugs that require watchful, regular monitoring, in an accessible tabular format, the essential laboratory addition to clinical observation of expected and unexpected changes resulting from drug treatment. Please note the increasing use of the disease modifying anti-rheumatic drugs (DMARDs), methotrexate, azathioprine, ciclosporin, cyclophosphamide and leflunomide has extended the need for monitoring adverse effects, particularly on the haemopoietic system. These drugs are almost always consultant-initiated and GPs should seek precise follow-up protocols from the consultant concerned. The same applies to the even more toxic cytokine modulators adalimumab, anakinra, etanercept and infliximab.