Anaes Vivas · Applied cardiovascular & respiratory physiology
Data viva — plasma protein binding and free fraction
A Primary data viva — read a free-fraction-vs-albumin graph; explain that only free drug is active; predict that hypoalbuminaemia raises the free fraction of acidic drugs (warfarin) while the acute-phase rise in alpha-1-acid glycoprotein lowers the free fraction of basic drugs (lidocaine); give the clinical consequence for highly bound drugs.
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A graph plots the free fraction (Y-axis) of two drugs against plasma albumin concentration (X-axis): warfarin (an acidic drug, about 99 percent bound to albumin, free fraction rising sharply as albumin falls) and lidocaine (a basic drug bound chiefly to alpha-1-acid glycoprotein, free fraction nearly flat across albumin concentrations). Interpret the graph, explain why only the free drug is active, and predict the effect of hypoalbuminaemia and of the acute-phase response.
References3ShowHide
- [1]Enlo-Scott Z, et al. A framework for plasma protein binding. J Pharm Sci, 2026.PMID 42309206
- [2]Valko K, et al. Biomimetic binding and volume of distribution. ADMET DMPK, 2026.PMID 42100636
- [42309207]Bersten AD, Soni N (eds) Oh's Intensive Care Manual. 8th edition, Elsevier, 2018.