Pharmacology Question

  1. 0
    I have a question from my graduate pharmacology class and have been trying, and trying to find an answer! If anyone has any help or insight it would be greatly appreciated!

    Ques. A comatose patient is admitted to the Emergency Department four hours after taking an overdose of phenobarbital. The plasma level of the drug at the time of admission is 100mg/L, and the apparent volume of distribution, half life, and clearance of phenobarbital are 35L, 4 days, and 6.1L/day. Respectively. The ingested dose was approximately:
    a.) 1g, b.) 3.5g, c.) 6.1g, d.) 40g, e.) 70g, f.) 110g

    I was looking for a dose/plasma ratio or some type of formula and have been unsuccessful!

    Get the hottest topics every week!

    Subscribe to our free Nursing Insights newsletter.

  2. 2 Comments...

  3. 1
    Not sure if it is appropriate to give a graduate student an answer, an answer I am 100% is in the book or lecture.
    tokebi likes this.
  4. 0
    If the clearance is 6.1L/day, that's about 0.2542L/hr, which means about 1.01667L in those 4 hours since ingestion. So, if plasma drug level was 100mg/L on arrival, the level was at least (100mg/L)x(1.01667L)=101.667mg four hours ago. But I'm really talking out of my behind... I don't know about pharmacology. I have no idea how apparent distribution and half-life are supposed to figure into the equation.

    I suggest pharmacokinetics chapter of your textbook.

    Or, if the distributed amount is supposed to be in equilibrium with plasma level, that would mean the total of 3500mg=(100mg/L)x35L, at the time of the test. I'm really just throwing out ideas. I don't know what I'm talking about...

    If you ever figure it out, will you post? I'm very curious...
    Last edit by tokebi on Sep 15, '12


Nursing Jobs in every specialty and state. Visit today and Create Job Alerts, Manage Your Resume, and Apply for Jobs.

A Big Thank You To Our Sponsors
Top