Transcript Drug calculation formula

Drug calculation formula
Strength required
volume of stock
Strength of hand X
1
= volume required
How many 50 mg tabs should be given for
a dose of 75mg?
75 x 1
3
50
1 =
2 = 1 1/2

Ordered: 15mg. Stock on hand 30mg. How many
tablets?
15 x 1 = 1
30
2 tab
 Ordered 300mg. Stock is 200mg in one tab. How
many tabs?
300 x 1 = 1 1/2
200
Patient is ordered 0.25mg of digoxin. The digoxin
available is in tabs containing 125mcg. How many
tabs should the patient receive?
Steps:
Convert 0.25mg to mcg
1mg = 1000mcg
0.25 mg = 250mcg
then apply formula:
250/ 125 x 1 tab = 2 tabs
A patient is ordered 150mg of aspirin. On hand are
tablets of 300mg.How many tablets do I give?
150/300 x 1/1 = ½ tab.

The stock on hand of diazepam is 5 mg. How
many tablets are to be administered if the
order is for 12.5mg?
12.5/5 x 1/1 = 125/50 x 1/1 = 5/2 x 1/1 = 2.5
tabs
A syrup contains penicillin 125mg/5ml. How much syrup do
I administer for 250mg?
250/125 x 5/1 =
2/1 x 5/1 = 10/1 = 10 ml
480mg of Paracetamol is prescribed. The stock solution
is 120mg in 5ml. How many ml do I administer?
480/120 x 5/1 = 4/1 x 5/1 = 20/1 = 20 ml