Abstract
Historically, it has been assumed that only free drug concentration is the pharmacologically active species. This article reviews the theoretical pharmacological and pharmacokinetic justifications for monitoring free drug levels. The determinants likely to influence plasma protein binding and the free concentrations of drugs are delineated. The different methods which can be used for determining free drug level are presented. Their advantages and drawbacks as well as their reliability and suitability for routine clinical practice are discussed. Currently, antiepileptic drugs such as valproic acid, phenytoin, carbamazepine and a few antiarrhythmic drugs meet the theoretical criteria justifying free drug level monitoring. Conditions causing alteration in free concentrations of these drugs are reported. But, for all these drugs, there is a considerable lack of data establishing the correlations between therapeutic or toxic response and free concentration. Presently, our capability to interpret correctly the free drug level data is still limited. In the future, much more effort must be devoted in order to provide sufficient information on the clinical relevance of free drug concentration.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
