Pharmacokinetics Tutoring

Constant rate infusion Therapeutic Regimen 1 Constant rate infusion

Constant rate infusion A drug is administered via continuous infusion at a rate of 60mg/h, resulting in a steady state plasma concentration of 5mcg/mL. IF the plasma concentration is intended to be doubled to 10 mcg/mL, the infusion rate must be: A. left he same B. Increaed by 30mg/h C. Increased by 60 mg/h D. increased by 120mg/h E. decreased by 30 mg/h

Constant rate infusion

Loading and maintenance dose You and your team determine that your patient has an increase in Volume. Which of the following needs to be done in his regimen? A. Increase in LD and MD B. Increase LD; same MD C. Same LD; increase MD D. Both remain the same. B

Loading and maintenance dose RW is a 30 yo WM who is beginning therapy on aminophylline. The team has decided to give him a LD. The Css the team would like to achieve is 10 mg/L of theophylline. The population values are Vd=40L and CL=3.3L/hr. What is the LD and MD of aminophyllne? LD A. 400mg B. 450mg C. 500mg D. 550mg MD A. 29mg/h B. 50mg/h C. 36mg/h D. 40mg/h

Constant rate infusion ZW received a 1 gram dose of ceftriaxone over a 30 minute infusion. What is the patients clearance if you measure the concentration of 10.2mg/L at 15 minutes. Assume k=0.067hr-1 A. 2.8L/h B. 3.3L/h C. 3.9L/h D. 4.5L/h

Constant rate infusion TB is a 76 yo WF who is experiencing toxicity from drug X on a current regimen of 90mg/h. After 6 days of therapy, a steady state blood level is drawn and found to be 23 mg/L. TR is 5-15 mg/L. If this infusion is stopped, how long until the patient would be at 10mg/L? Assume Vd of 50L. A. 10.6 h B. 13.9 h C. 15 h D. 17.7 h

Constant rate infusion What should the new infusion rate be? 10mg/h 20mg/h 30mg/h 40mg/h

Constant rate infusion How long until the patient will be at new Css? 33 hours 44 hours 55 hours 66 hours

Time to css The time to reach Css is determined by: A. Rate of infusion (R0) B. Elimination rate constant (K) C. Absorption rate constant (Ka) D. The maximum concentration (Cmax)

Continuous IV infusion CL=4.6L/h, V=35L, k=0.143 Therapeutic Range= 10-15 (Assume we are targeting 13mg/L) LD=___________ (Assume it is given over 45 minutes) MD=___________ Calculate the concentrations at the following time points (Assume both the LD and MD infusions are started at the same time): 20 minutes

Continuous iv infusion 1 hour, 10 minutes 24 hours

multicompartment What is an acceptable way to overcome the issue with giving a loading dose of a drug exhibiting multi-compartment characteristics? A. Give as a continuous infusion B. Give a LD based on the Volume of the central compartment C. Give a LD based on post-equilibrium Vd D. Multiple small bolus injections.

multicompartment When is the best time to obtain a drug sample if a patient is given an IV drug that has multicompartment characteristics? A. Right after you give the IV drug B. There’s no good time to obtain the drug sample C. Wait until distribution is over

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