WEBVTT
Kind: captions
Language: en
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Now based on the K ratio,
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we can also construct normal graph such as this.
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This is for specific for tobramycin.
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Percent of normal dosage.
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Creatinine clearance on the top.
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And the serum creatinine at the bottom.
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And It is a straight line.
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Therefore you can interpolate a dose for a specific kidney function.
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Let's look at another example.
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This example says patient JT is 58 year old and 170 centimeter in height and the 58.3 kilo in weight.
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His serum creatinine is 2.
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What should be the loading dose as a percent of normal dose based on this half-life?
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Now, first you need to calculate the ideal body weight.
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And this is based on an equation that you can find from any pharmacokinetic textbook.
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However, I simply give you the answer.
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The ideal body weight is 66 kilogram by the formula.
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Then estimate his creatinine clearance by Cock-croft equation
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which turns out to be 33 mL per minute.
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Again I will leave the detailed calculation to yourself.
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And then predict tobramycin half-life for this patient
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based on this specific formula
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which says ke is equal to 0.0024 times creatinine clearance plus 0.01.
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And the answer turn out to be half-life is equal to 7.7 hour.
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So if we read the next chart.
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We will find out that
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the uremic dose for this patient should be
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based on q8h should be about 50% of normal dose.
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And this is where you find the answer.
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The first column creatinine clearance is 33.
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The second column the half-life is 7.7 hour.
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And then third column, therefore, the dose should be 50% of normal.