A 45-year-old man is started on an intravenous neuroleptic drug for treatment of seizures in the hospital. He achieves a steady state plasma drug concentration of 20 mg/L. After no seizure activity for 48 hours, plans are made to discharge him on an oral form of his seizure drug. The drug's clearance rate is 0.25 L/hr and bioavailability is 50%. Which of the following is an appropriate oral dosing regimen?

Question

Quizplus · Accepted Answer

The appropriate oral dosing regimen can be calculated using the formula: Oral dose = (Desired plasma concentration x Clearance) / Bioavailability. Here, (20 mg/L x 0.25 L/hr) / 0.5 = 10 mg/hr. For a 12-hour dosing interval, the dose would be 10 mg/hr x 12 hr = 120 mg. Thus, 120 mg twice per day is appropriate.

A 45-Year-Old Man Is Started on an Intravenous Neuroleptic Drug