Drug Dosing and Estimated Renal Function - Any Step Forward from Effersoe?

Drug dosing in accordance with the renal function is a long-standing challenge to clinicians. For many years it has been evident that in many clinical situations there is no easy way to correctly dose any drug that is mainly cleared by the kidneys. Despite the development of many formulas for estimating the glomerular filtration rate, they all have serious shortcomings. Much effort has been put in to develop estimation formulas to evaluate the renal function as an alternative to direct methods with the aim of safely dosing drugs that are mainly cleared by the kidneys. Both creatinine- and cystatin C-based formulas with additional clinical and biochemical parameters deduced from association studies with methods to measure the glomerular filtration rate (mGFR) have been developed. None of them have been good enough to perform safely in the wide range of situations in daily clinical praxis. Despite serious limitations, there has also been a tendency to use estimated GFR (eGFR) as a "hard" clinical endpoint in clinical studies. This has increased the risk of misinterpretation and has led to conclusions that are not necessarily supported by data. Finally, new methods of testing drug toxicity and the use of pharmacological support in order to fix the right doses are mentioned in this short overview of studies; possible problems that are encountered using eGFR instead of mGFR in the clinic and in research are also mentioned in this report.