Optimizing a Phenytoin Dosage Regimen

At the clinic you have a new patient (Q.D.), age 20 years and weight 79 kg. An initial dose of 410 mg/day was recommended. The patient was instructed to take this dose each day for a few weeks and return for a plasma sample. This plasma sample was found to contain 7.4 mg/L phenytoin. This was somewhat low so you need to calculate a new dose per day with the aim of achieving an average plasma concentration of 15 mg/L. For this calculation you can assume that the patient has a Km value of 4 mg/L (a population average value).

A useful equation

Equation 31.1.1 Dose Rate equals Rate of Elimination

Last update: Fri 25 Jul 2008 04:27:02 pm

Practice problem answers may not be available on occasion. These practice problems may be used for graded homework from time to time. For any given problem set this will probably be for one or two weeks at most. Please try later.