03-22-2008, 02:55 PM
ddd
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renal pharm question - ultradocmansu
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03-22-2008, 02:59 PM
e?
it takes 4-5 half lives before it reaches steady state u gave both options, still 125 mins is better i think
03-22-2008, 03:17 PM
As for the equation we used earlier,
Infusion rate = Cl/ steady state plasma level or, Cl= infusion rate/ ss plasma level One way to understand it is, in renal pharma, Cl= excretion rate/ plasme conc. In a steady state, excretion rate = infusion rate or simply, in=out Using interchangeably, Cl= excretion rate/plasma conc or Cl= infusion rate/ss plasma level
03-22-2008, 04:00 PM
Sorry 4 delay, was bsy
1)A continuous intravenous infusion of a medication with a half-life of 25 minutes is started on a patient in the ICU. Approximately how long will it take before steady-state plasma levels of the drug are reached? A.25 minutes B.50 minutes C.75 minutes D.100 minutes E.125 minutes Explanation Hide Explanation Choice (D) is the correct answer. A good rule of thumb to remember is that it takes approximately 4 half-lives for a drug to reach steady-state plasma concentrations. In this case, the half-life of the drug is 25 minutes. 25 x 4 = 100 minutes to reach steady-state plasma drug levels. The other choices are incorrect. 2)A new antifungal medication is being tested in Phase I clinical trials. Examination of the pharmacokinetic properties of the drug reveals that the half-life of the drug is 6 hours. If a continuous intravenous infusion of this drug were started on a research subject, how long would it take to reach 75% of steady state? A. 3 hours B. 6 hours C. 9 hours D. 12 hours E. 18 hours F. 24 hours Explanation: The correct answer is D. The rule of thumb is that the plasma concentration will reach 50% in one half-life, 75% in two half-lives, 87.5% in three half-lives, etc., so that the difference between the current drug level and 100% halves with each half-life. In this instance, it takes two half-lives to reach 75%. The half-live of this drug is 6 hours, so two half-lives is 12 hours.
03-22-2008, 10:12 PM
good review of all farma calculation qs . although i felt q 1 is ambiguous. thanx okt3
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