Tablet Dosage Calculations
Most of the examples in this lesson refer to medication provided in tablet form; however, this also applies to other dry oral medications such as pills and capsules.
Examples
These two examples show the dosage ordered, the stock availability, a stepbystep look at the dimensional analysis, and the result. These example emphasize the three major steps in the dimensional analysis.
Ordered: 750 mg of xyz On Hand: 250 mg tablets  
Set up the ratios: 
 
Cancel the labels: 
 
Complete the math: 
 
Result: 3 tablets 
Ordered: 150 mg of xyz On Hand: 100 mg tablets  
Set up the ratios: 
 
Cancel the labels: 
 
Complete the math: 
 
Result: 1^{1}/_{2} tablets 
The preceding examples emphasize the stepbystep procedure for determining how to deliver the prescribed dosage. The form you will actually use is a bit simpler — you don't have to break down each step in a table. Here is an example of how you should actually perform these operations on a pad of paper.
Ordered: 10 mg of xyz.
On Hand: 20 mg tablets
10 x
1 tablet = 0.5 tablet 1 20 Result: 0.5 or ½ tablet
Tablet Dosage Drill
Work with this drill routine until you can consistently answer the questions correctly. Be sure to write out the DA sequence You should have no need for a calculator. Click the Answer button to see the correct answer to the question. 

RealWorld Examples
1. You are to administer Dilantin 300 mg PO to a patient. Dilantin is stocked in 100 mg capsules. You will administer _____ capsules.
300 x
1 capsules = 3 capsules 1 100
Ans: 3 capsules
2. Aspirin tablets are labeled 0.3 gm. How many tablets are needed for a dose of 600 mg?_____
First notice that the units are not the same — one is in grams and the other in milligrams. So change 0.3 gm to 300 mg. (You make the units the same by changing 600 mg to 0.6 gm, but you should always try to work with decimals that are 1 or greater). Then set up the ratios.
600 x
1 tablet = 2 tablets 1 300 Ans: 2 tablets
3. The doctor has ordered Diabinese tablets 0.25 gm for your patient. You have available Diabinese 100 mg tablets. You will administer _____ tablets to your patient.
Change the 0.25 gm to 250 mg in order to have both units the same.
250 x
1 tablets = 25 tablets 1 100 Ans: 2½ tablets
4. You are to administer Digoxin 0.375 mg PO to a patient. On hand are 0.25 mg tablets. You will administer _____ tablets.
0.375 x
1 tablets = 1.5 tablets 1 0.25 Ans: 1.5 or 1½ tablets
Tablet Dosage Word Problems
Work with this drill routine until you can consistently answer the questions correctly. You should have no need for a calculator. Click the Answer button to see the correct answer to the question. 
