VPA CALCULATOR

In blood, most drugs are bound to serum proteins. The fraction bound to proteins is considered to be pharmacologically inactive, as only the unbound (free) fraction is available for diffusion out of the vascular system to sites for pharmacological action... The valproic acid-protein binding depends on both the serum albumin concentration and the drug concentration. As a result, the free fraction of this drug is subject to more variation than other highly protein-bound antiepileptic drugs. In patients with hypoalbuminemia, the total serum concentration of valproic acid may offer poor clinical information; however, very few clinical laboratories routinely analyze the free concentration of the drug. Use this calculator to analyse the correct concentration of valproic acid.