Filling a Prescription
Scenario 1
• Charlie, a 3 year-old, neutered male, Corgi mix is
seen by Dr. Brown for vomiting and diarrhea
• Dr. Brown diagnoses Charlie with a gastrointestinal
tract infection and prescribes 2 mL Amoxi-Drop 50
mg/mL to be given BID for 7 days
• Amoxi-Drop is an oral suspension:
– Add required amount of water to the bottle and shake
vigorously
– #1 bottle 15 mL reconstituted with 12 mL water, #2 bottle
30 mL reconstituted with 23 mL water
– Discard unused portion after 14 days; refrigerate after
mixing
– Expires 6 months after prescription date
Texas A&M Veterinary Hospital
College Station, TX
Name: Charlie
Species: Canine
Date: 03/28/2015
Dr. Brown
Directions:
Give 2 mL by mouth every 12 hours for 7 days
Mix with 23 mL of water and shake vigorously before use
Refrigerate after mixing and discard after 14 days
Drug: Amoxi-Drop 50 mg/mL #2, No refills
Expiration: 9/28/2015
Keep out of reach of Children – For Veterinary use only
Scenario 2
• “Toothless” a 12 year-old, spayed female, Maine
Coon has been diagnosed with arthritis by Dr. Ag
and has a standing prescription for .25 mg Triam
Tabs to be taken once daily
– This is a monthly prescription and can be refilled between
visits
• Toothless will be seen in 2 months to re-evaluate
• Triam Tabs:
– Available in 2 strengths: 1.5 mg and .5 mg
– Store at room temperature
– Expire 1 year after prescription date
Texas A&M Veterinary Hospital
College Station, TX
Name: Toothless
Species: Feline
Date: 03/28/2015
Dr. Ag
Directions:
Give ½ tablet by mouth once daily
Store at room temperature
Drug: Triam Tabs .5 mg (15), 2 refills
Expiration: 3/28/2016
Keep out of reach of Children – For Veterinary use only
Calculating Percent Solutions
Terminology
•Solution- a mixture of two or more substances
•Solute - the substance dissolved in the liquid
solvent in a solution
•Solvent - the liquid that dissolves the solute in
a solution
Solution Ratios
• Weight in weight (W/W)
– number of grams of the drug = ___Xg drug__
g of the final product
100g product
• Weight in volume (W/V)
– number of grams of the drug = ___Xg drug__
mL of the final product
100mL product
• Volume in Volume (V/V)
– number of milliliters of the drug = ___XmL drug__
milliliters of the final product
100mL product
Solution Formulas
• Weight in weight (W/W)
– grams of active ingredient x 100
g of the final product
• Weight in volume (W/V)
– grams of active ingredient x 100
mL of the final product
• Volume in Volume (V/V)
– milliliters of active ingredient x 100
milliliters of the final product
Problem 1
• If there are 30g of dextrose in 500mL of the
solution, what is the percentage of solution?
• W/V ratio
– Grams of drug x 100
mL of final product
– 30g x_100
500mL
–6%
Problem 2
• Determine the percent solution of a 20mL vial of
800mg Gentamicin.
• W/V ratio
– Grams of drug x 100
mL of final product
– Strength of drug is given in mg, must convert to g
– 1000mg in 1 g, 800mg x 1g_____ = .8g
1000mg
– .8g x_100
20mL
– 4%