phenytoin has a plasma protein binding of about 90% that is exclusively attributed to albumin.?

[Maria S]

if a patient has a total phenytoin level of 15 mcg/ml, and has normal albumin, what would be the expected free phenytoin level?

[jc156392]

Loading dose or given daily to steady state? Either way complicated question. How about you figure it out yourself.

Relevant information for phenytoin
Oral availability ~ 90%.
Bound in plasma ~ 90%
Clearance ~ 6mg/kg/day
Volume distribution ~ 0.6 L/kg
Half-life 6 - 24 hrs. Although at doses giving therapeutic plasma concentrations, elimination of the drug is relatively slower (due to the change from first-order to zero-order kinetics)