Solutions
The attending veterinarian asks you to administer 120 mg of enrofloxacin (Baytril) IV slow over 20
minutes to a dog that is hospitalized in your clinic. The strength of injectable enrofloxacin is 2.27%,
how many milliliters of drug will you administer?
Answer: 5.3 ml
A 2.27% solution is 22.7 mg/ml. 120 mg divided by 22.7 mg/ml = 5.3 mls
A 120-pound Great Dane has presented with Gastric Dilatation Volvulus. The clinician has asked you
to quickly prepare the drug protocol. As a premedication, the dog is to receive 0.08 mg/kg of
Hydromorphone. How many milligrams will you administer?
Answer: 4.4 mg
To calculate milligrams administered the dog's body weight should be converted to kilograms. As a
general rule, the majority of medications are dosed in a milligram-per-kilogram dosing. Therefore all
body weights need to be converted to kilograms so that you are working in the same units.
120 lb/2.2 = 54.5 kg (There are 2.2 lbs per kilogram)
54.5 kg x (0.08 mg/kg) = 4.4 mg (Notice the "kg" will cancel out when you do the math)
If your answer was 9.6 mg, you did not convert the body weight into kilograms.
How many milligrams are in 100 ml of a 3% solution?
Answer: 3,000 mg
A 3% solution is equal to 30 mg/mL.
Now take 100 mL X 30 mg/mL = 3000 mg= 3 grams (since there are 1000 mg in 1 gram)
How many milliliters should be administered to a 100-kg patient that needs 50 mg of a 2.5% solution?
Answer: 2 ml
Percent is equal to weight (in Grams) / 100 parts volume (in mLs)
(This is based on water since 1 mL weighs 1 Gram):
Example: A 3% solution: 3 Grams / 100 mL or 3000 mg / 100 mL or 30 mg/mL
The easiest way to remember is to just add a zero onto any percentage for the milligrams (i.e. 2%
solution = 20 mg/ml; 10% solution = 100 mg/ml, etc.)
In this situation a 2.5% solution is equivalent to 25 mg/ml. Therefore:
50 mg / (25 mg/ml) = 2 ml
A 4-kg puppy is in need of subcutaneous fluids due to dehydration. The doctor prescribed a dose of 20
ml/kg. How many milliliters should this patient receive?
Answer: 80 ml
To obtain the answer the following math should have been performed:
4 kg x (20 ml/kg) = 80 ml
Notice the kilograms were canceled out.
, A dog presents with a history of coughing and rapid breathing. Radiographs confirm congestive heart
failure (see image). You are asked to administer 2 mg/kg of furosemide IV. The concentration of
furosemide is 50 mg/mL. The dog weighs 25 pounds. How many milliliters should you administer to
this patient?
Answer: 0.44 mL
The dog is 25 pounds.
25 pounds/2.2 pounds per kg= 11.3 kg
Now multiply the dog's weight in kg by the dose you need (2mg/kg):
11kg X 2mg = 22 mg
The dog needs 22 mg. Now divide this dose by the concentration of furosemide (50 mg/mL):
22mg/ 50 = 0.44 mL
You are instructed to administer 12 liters of sterile isotonic IV fluids via a fluid pump over the next 24
hours. What is the appropriate fluid rate to administer this volume of IV fluids?
Answer: 500 mL/hour
12 liters (12000 mLs) divided by 24 hours would equal 500 mLs/hour.
A 12 pound dog comes into the clinic with a history of vomiting for the last 24 hours. The doctor asks
you to give an injection of Cerenia (maropitant) at a dose of 0.45mg/lb. Cerenia has a concentration of
10mg/ml. How many milliliters will be given to the dog?
Answer: 0.54 mls
(12lb) X (0.45mg/lb)=5.4mg (lbs cancel)
5.4mg divided by 10mg/ml=0.54mls (the milligrams cancel)
A 60-kg dog needs to be sedated with dexmedetomidine and butorphanol. The doctor would like a
dose of 10 ug/kg for dexmedetomidine and 0.1 mg/kg for butorphanol. Dexmedetomidine comes in a
1 mg/ml solution, and butorphanol is in a 10 mg/ml solution. How many milliliters of each medication
will need to be administered for the patient's sedation?
Answer:
0.6 ml of dexmedetomidine and 0.6 ml of butorphanol
For dexmedetomidine, do the following math:
60 kg x (10 ug/kg) = 600 ug
Note the units and convert to work with milligrams as the solution is in milligrams per milliliter.
600 ug / (1000 mg/ug) = 0.6 mg
0.6 mg / (1 mg/ml) = 0.6 ml
For butorphanol, do the following math:
60 kg x 0.1 mg/kg = 6 mg
6 mg / (10 mg/ml) = 0.6 ml