Q. 2.64 - An Introduction to General, Organic, and Biological Chemistry

Question

Using conversion factors, solve each of the following clinical problems:

a. The physician has ordered $1.0 \mathrm{g}$ of tetracycline to be given every six hours to a patient. If your stock on hand is $500-\mathrm{mg}$ tablets, how many will you need for one day's treatment?

b. An intramuscular medication is given at $5.00 \mathrm{mg}/\mathrm{kg}$ of body weight. What is the dose for a $180-\mathrm{lb}$ patient?

c. A physician has ordered $0.50 \mathrm{mg}$ of atropine, intramuscularly. If atropine were available as $0.10 \mathrm{mg}/\mathrm{mL}$ of solution, how many milliliters would you need to give?

d. During surgery, a patient receives $5.0 \mathrm{pt}$ of plasma. How many milliliters of plasma were given?

Step-by-Step Solution

Answer

(a) The $8 \mathrm{tablets}$ will be needed for one day's treatment

(b) The $409 \mathrm{mg}$ dose for the patient is required

(c) The $5 \mathrm{mL}$ of atropine is needed to give

(d) The $2400 \mathrm{mL}$ of plasma are given  

Part (a) Step 1: Given information

We need to find the no. of tablets needed for one day's treatment 

Part (a) Step 2: explanation

We know that

$\frac{1 \mathrm{g}}{6 \mathrm{h}}, \frac{1 \mathrm{day}}{24 \mathrm{h}}, \frac{1 \mathrm{tablet}}{500 \mathrm{mg}}$

Therefore, no. of tablets needed are,

$1 \cancel{\mathrm{day}}\times \frac{24 \cancel{\mathrm{h}}}{1 \cancel{\mathrm{day}}}\times \frac{1 \cancel{\mathrm{g}}}{6 \cancel{\mathrm{h}}}\times \frac{1000 \cancel{\mathrm{mg}}}{1 \cancel{\mathrm{g}}}\times \frac{1 \mathrm{tablet}}{500 \cancel{\mathrm{mg}}}=8 \mathrm{tablets}$

Part (b) Step 1: Given information

We need to find the dose for a $180 \mathrm{lb}$ patient 

Part (b) Step 2: Given information

We know that 

$1 \mathrm{kg}=2.20 \mathrm{lb}$

And $5 \mathrm{mg}=1 \mathrm{kg}$

Therefore, dose for a $180 \mathrm{lb}$ patient is,

$\frac{1 \cancel{\mathrm{kg}}}{2.20 \cancel{\mathrm{lb}}}\times \frac{5 \mathrm{mg}}{1 \cancel{\mathrm{kg}}}\times 180 \cancel{\mathrm{lb}}=409 \mathrm{mg}$

Part (c) Step 1: Given information

We need to find the milliliters needed to give 

Part (c) Step 2: Explanation

We know that

$0.10 \mathrm{mg}=1\mathrm{mL}$

Therefore,

Milliliters of atropine needed to give is, 

$\frac{1 \mathrm{mL}}{0.10 \cancel{\mathrm{mg}}}\times 0.50 \cancel{\mathrm{mg}}=5 \mathrm{mL}$

Part (d) Step 1: Given information

We need to find the milliliters of plasma given 

Part (d) Step 2: Explanation

We know that

$1 \mathrm{pt} =473 \mathrm{mL}$

Therefore, 

Milliliters of plasma given are,

$\frac{473 \mathrm{mL}}{1.76 \cancel{\mathrm{pt}}}\times 5 \cancel{\mathrm{pt}} =2365 \mathrm{mL}\approx 2400 \mathrm{mL}$

As there are two significant figures.