A drug has the following pharmacokinetic parameters: - Systemic clearance = 75 L/hr - Volume of distribution = 1500 L - Fraction excreted unchanged in urine = 0.04 (i) Calculate an intravenous infusion rate that would maintain a steady-state blood concentration of 0.2 mg/L. (2 marks) (ii) Calculate the elimination half-life and time to steady-state. (2 marks) (iii) Calculate a loading dose that would give a blood concentration of 0.2 mg/L. Comment on the implications of the use of a loading dose for the time taken to reach steady-state. (3 marks) (iv) Calculate the oral dose rate that would be necessary to maintain a steady-state blood concentration of 0.2 mg/L. (Assume absorption from the gastrointestinal tract is complete and liver blood flow is 90 L/hr)
Added by Christopher T.
Step 1
Plugging in the values, we get: Infusion rate = (0.2 mg/L x 75 L/hr) / 0.04 Infusion rate = 375 mg/hr (ii) The elimination half-life can be calculated using the formula: t1/2 = 0.693 x Vd / Cl where Vd is the volume of distribution and Cl is the systemic Show more…
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