Monday, December 7, 2015

Dosage Calculation - Mass for Mass Questions

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By DosageHelp.com

Mass for Mass Questions
Given an amount of mass per tablet, how many tablets do you require?

Formula:

$\overline{)\frac{{\mathbf{Ordered}}}{{\mathbf{Have}}}={\mathbf{Y\left(Tablets required\right)}}}$

Example: Metroprolol (Lopressor), 25 mg PO, is ordered. Metropolol is available as 50 mg tablets. How many tablets would the nurse administer?
$\frac{{\mathbf{Ordered}}}{{\mathbf{Have}}}={\mathbf{Y\left(Tablets required\right)}}$
$\frac{{\mathbf{25 mg}}}{{\mathbf{50 mg}}}=\overline{)\frac{{\mathbf{1}}}{{\mathbf{2}}}{\mathbf{tablets}}}$
Alternatively, 50 mg = 1 tablet
Therefore 25 mg = 1/50 x 25 = 0.5 tablets

Example: Potassium Chloride is available as 10 mg per tablet. Potassium Chloride (K-Dur), 40 mg is ordered. How many tablets would the nurse administer?
$\frac{{\mathbf{Ordered}}}{{\mathbf{Have}}}={\mathbf{Y\left(Tablets required\right)}}$
$\frac{{\mathbf{40 mg}}}{{\mathbf{10 mg}}}=\overline{){\mathbf{4 tablets}}}$
Alternatively, 10 mg = 1 tablet
Therefore 40 mg = 1/10 x 40 = 4 tablets

Example: (From Ngee Ann Polytechnics Dosage Calculation Worksheet)
ORDER: Drug C 0.35 mg P.O.
AVAILABLE: Drug C tabs 0.7 mg

${\mathbf{\text{GIVE:}}}\overline{)\phantom{\rule{30pt}{12pt}}}{\mathbf{\text{Tab(s)}}}$
$\frac{{\mathbf{Ordered}}}{{\mathbf{Have}}}={\mathbf{Y\left(Tablets required\right)}}$
$\frac{{\mathbf{0.35 mg}}}{{\mathbf{0.7 mg}}}=\overline{)\frac{{\mathbf{1}}}{{\mathbf{2}}}{\mathbf{tablets}}}$
Alternatively, 0.7 mg = 1 tablet
Therefore 0.35 mg = 1/0.7 x 0.35 = 0.5 tablets

Continue (Dosage Calculation - Mass for Mass Questions - (2))

Reference