[TNF inhibitors: the role of drug levels].

There is a variation in the pharmacokinetics of TNF inhibitors. Measurement of drug levels may help to identify patients in whom treatment can be optimised. Various factors influence the pharmacokinetics of TNF inhibitors; one of the most important factors is immunogenicity. There is inter-patient variation in the TNF inhibitor dose needed to achieve clinical effectiveness, as well as variation in the dose needed to maintain clinical effectiveness. Immunosuppressive co-medication plays an important role in the optimisation of TNF inhibitor therapy via an effect on inflammation and immunogenicity.