Problem: An 82 kg adult patient is given an IV bolus loading dose of 350 mg of theophylline, and a continuous infusion of 60 mg/hour is begun at the same time. What is the drug plasma concentration 20 hours later if t1/2 = 7.30 hours and Vd = 0.52 L/kg? (b) What is the total dose of theophylline given over this 20 hour period? (c) If the infusion rate in part (a) of this question was increased to 70 mg/hour, determine the drug plasma concentration 20 hours later? (d) The 350 mg loading dose is now given as a 30 min infusion. (i) If the continuous infusion of 60 mg/hour begun at the same time remains the same, determine the drug plasma concentration 20 hours later? (ii) Has the change in loading dose administration (i.e. from IV bolus loading dose to 30 min infusion) significantly changed the drug plasma concentration 20 hours later? (e) Briefly explain why you would give a loading dose as a 30 min IV infusion rather than as an IV bolus dose. Need Assignment Help?