Pharmacy Calculations
Study online at https://quizlet.com/_huikms
1. express 1:100 as a percent: % = (1/100) X 100====>>1%
2. How many milligrams of active drug are in 100 ml
of a 1% solution?: 0.01 = (x gm/100ml)
x = 1 gm (1000 mg)
3. H ow many milliliters of a 5% solution would be
needed to deliver500 mg of active drug?: 0.05 = (0.5 gm / x ml)
x = 10 ml
4. Calculating Drug Doses & Percentages
To calculate drug dosages, remember one basic
statement:
One gram or ml of drug in 99 ml of diluent will yield a 1%
solution. Therefore, 1 ml of a 1% solution contains .01 gm
(10 mg) of the drug.: • The formula that proves this statement is:
% (in decimals) = amount of solute (gm)/total amount of solution (ml)
5. Mixing Solutions
• When mixing two solutions to obtain a desired
drug percentage, the following formula is used:: (amount of solute needed)/(amount of
solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
6. Mixing Solutions
• Example
- prepare 5 ml of a 5% solution of acetylcysteine,
using 20% acetylcysteine and normal saline: (x/5) = (5/20)
therefore X = (25/20)
x = 1.25
, Pharmacy Calculations
Study online at https://quizlet.com/_huikms
To prepare 5 ml of 5% acetylcysteine, mix 1.25 ml of the 20% acetylcysteine with 3.75 ml normal saline.
7. 1. A .3 ml dose of 5% Metaprel contains how many mg metaproterenol?: % (in
decimals) =
(amount of solute (gm))/(total amount of solution (ml)
8. 2. A .5 ml dose of 1:200 Isuprel contains how many mg isproterenol?
First, convert 1:200 to a percentage (in decimal form): % (in decimals) =
(amount of solute (gm)/total amount of solution (ml))
9. 3. How many ml of 1:200 Proventil would be needed to deliver 5 mg
albuterol?: % (in decimals) =
( amount of solute (gm)/total amount of solution (ml))
10. 4. What is the percentage strength of a solution of Ventolin that
contains 5 mg albuterol per ml?: % (in decimals) =
( amount of solute (gm)/total amount of solution (ml))
11. 5. What is the ratio strength of an epinephrine solution that contains 1 mg
epinephrine per ml?: % (in decimals) =
( amount of solute (gm)/total amount of solution (ml))
12. 1. Prepare 250 ml of 1% NaCl using H2O and 10% NaCl solution.: (amount of solute
needed)/(amount of solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
13. 2. Prepare 50 ml of 5% acetylcysteine solution using NS and 20% acetylcys-
teine: (amount of solute needed)/(amount of solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
14. 3. Prepare 2 L of 20% NaHCO3 solution using H2O and NaHCO3 crystals.: -
(amount of solute needed)/(amount of solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
15. 4. Prepare 1 L of NS using H2O and NaCl crystals.: (amount of solute needed)/(amount
of solution desired )=
Study online at https://quizlet.com/_huikms
1. express 1:100 as a percent: % = (1/100) X 100====>>1%
2. How many milligrams of active drug are in 100 ml
of a 1% solution?: 0.01 = (x gm/100ml)
x = 1 gm (1000 mg)
3. H ow many milliliters of a 5% solution would be
needed to deliver500 mg of active drug?: 0.05 = (0.5 gm / x ml)
x = 10 ml
4. Calculating Drug Doses & Percentages
To calculate drug dosages, remember one basic
statement:
One gram or ml of drug in 99 ml of diluent will yield a 1%
solution. Therefore, 1 ml of a 1% solution contains .01 gm
(10 mg) of the drug.: • The formula that proves this statement is:
% (in decimals) = amount of solute (gm)/total amount of solution (ml)
5. Mixing Solutions
• When mixing two solutions to obtain a desired
drug percentage, the following formula is used:: (amount of solute needed)/(amount of
solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
6. Mixing Solutions
• Example
- prepare 5 ml of a 5% solution of acetylcysteine,
using 20% acetylcysteine and normal saline: (x/5) = (5/20)
therefore X = (25/20)
x = 1.25
, Pharmacy Calculations
Study online at https://quizlet.com/_huikms
To prepare 5 ml of 5% acetylcysteine, mix 1.25 ml of the 20% acetylcysteine with 3.75 ml normal saline.
7. 1. A .3 ml dose of 5% Metaprel contains how many mg metaproterenol?: % (in
decimals) =
(amount of solute (gm))/(total amount of solution (ml)
8. 2. A .5 ml dose of 1:200 Isuprel contains how many mg isproterenol?
First, convert 1:200 to a percentage (in decimal form): % (in decimals) =
(amount of solute (gm)/total amount of solution (ml))
9. 3. How many ml of 1:200 Proventil would be needed to deliver 5 mg
albuterol?: % (in decimals) =
( amount of solute (gm)/total amount of solution (ml))
10. 4. What is the percentage strength of a solution of Ventolin that
contains 5 mg albuterol per ml?: % (in decimals) =
( amount of solute (gm)/total amount of solution (ml))
11. 5. What is the ratio strength of an epinephrine solution that contains 1 mg
epinephrine per ml?: % (in decimals) =
( amount of solute (gm)/total amount of solution (ml))
12. 1. Prepare 250 ml of 1% NaCl using H2O and 10% NaCl solution.: (amount of solute
needed)/(amount of solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
13. 2. Prepare 50 ml of 5% acetylcysteine solution using NS and 20% acetylcys-
teine: (amount of solute needed)/(amount of solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
14. 3. Prepare 2 L of 20% NaHCO3 solution using H2O and NaHCO3 crystals.: -
(amount of solute needed)/(amount of solution desired )=
(concentration of desired solution)/
(concentration of on - hand solution)
15. 4. Prepare 1 L of NS using H2O and NaCl crystals.: (amount of solute needed)/(amount
of solution desired )=
