Dose Calculations

Instructor Trish Carr, LVT

Right Administration Principles

Right Patient: Confirm you're treating the correct animal to prevent mistakes. This includes verifying the animal's identification with records or tags to avoid mix-ups, especially in multi-animal facilities.
Right Medication: Ensure the medication matches what’s prescribed. Always cross-check the medication's name, dosage form (tablet, solution, etc.), and the administration route (oral, IV, IM, etc.) against the veterinary order.
Right Dosage: Calculate the correct dosage based on the animal's weight or surface area. Use specific formulas tailored for various species to minimize errors.
Right Units: Use the correct measurement units throughout the process. Be mindful of unit conversions, especially between milligrams and grams or milliliters and liters.
Right Time: Administer medications at the right times as indicated in the treatment plan. This may include special considerations, such as the time of day or requirements for food.

In-Lab Protocol

When performing calculations in a lab setting, it is mandatory to have your calculations verified by a lab instructor or assistant before drawing up any medications. This verification process helps minimize errors and ensures safe practice by providing a second set of eyes on crucial calculations. Always ask for clarification if unsure about specific details.

Essential Definitions

Understanding common terminology related to drug calculations is vital to ensure accuracy. Familiarize yourself with terms like dosage, concentration, volume, and administration routes to enhance comprehension.

Rounding Rules for Veterinary Technicians

Guidelines to follow when rounding numbers:

If the number is greater than or equal to 5: Round up.
If the number is less than 5: Round down.

Examples of Rounding to 0.01:

0.1822 rounds to 0.18.
0.1872 rounds to 0.19.
0.355 rounds to 0.36.

Selecting Syringes

Choose the appropriate syringe size based on the volume needed. Common sizes include:

1/2 mL
1 mL
1.5 mL
2 mL Always ensure the syringe is appropriate for the dosage and the animal size. Using the correct syringe size aids in accurate dosing and minimizes stress on the animal during administration.

Units of Measurement

MILLIGRAMS (mg): A unit of mass equal to one-thousandth of a gram.
GRAMS (g): A basic unit of mass in the metric system, equal to 1000 milligrams.
KILOGRAMS (kg): A unit of mass equal to 1000 grams, often used for larger animals.
MILLILITERS (mL): A unit of volume, commonly used for liquid medications, equivalent to one cubic centimeter.

Steps for Dose Calculation

Step 1 write down info given.

ex: dosage is 10 mg/kg, concen

Step 2a Determine the units for the medication as it will be administered to the animal. Place these units to the right of the equal sign (e.g., = mL).

Step 2b put dosage on the first thing on left side of the equal sign

Step 3aWhen calculating medication, ensure to add numbers that help cancel the units appropriately. Example Calculation:10 kg X 15 X = _____ mL1 1000 250 1 X

Step 3b[Content for step 3b is missing]

Step 4[Content for step 4 is missing]

Essential Reminders

Round only once!: Do not round multiple times throughout the calculation process to avoid compounding rounding errors.
Show all units!: Ensure that each step of your calculation displays all units clearly to avoid confusion and maintain clarity.
Cancel all units!: Always simplify units appropriately during calculations to ensure that the resulting calculation is valid.
Double-check your work!: Confirm all calculations to prevent administering incorrect dosages, which can have serious consequences for the patient's health.
Round to the syringe size!: Ensure the final dosage is appropriate for the syringe that will be used, taking into consideration both the maximum capacity of the syringe and comfort during administration.

Documentation in Medical Records

Sample entry for documentations:

S: BAR (Bright, Alert, Responsive)
O: 250g
PE-NR (Physical Examination - No Remarkable findings)
P: Performed brief PE. Administered 2.55 mg (0.17 mL) Acepromazine IP lower right abdomen.

P. Carr

Practice Problem 1

Scenario: Administering Sleepystuff® to a 2 kg rabbit. Dosage = 0.75 mg/kg; Concentration = 10 mg/mL.Required Calculation: How much to administer IM?Result: 0.15 mL.

Further breakdown:10 X = 1.5 mg.

Documentation for Practice Problem 1

Sample entry for documentations:

S: BAR
O: 2 kg
PE-NR
P: Performed brief PE. Administered 1.5 mg (0.15 mL) Sleepystuff IM left epaxial muscle.

P. Carr

Practice Problem 2

Scenario: Administering Sleepystuff® to a 200 g rat. Dosage = 10 mg/kg; Concentration = 15 mg/mL.Breakdown of calculation:10 kg X 15 X 200g = _____ mLFinal Calculation: 0.13 mL, ensures correct dosage.Result of Practice Problem 2Calculated Result: 0.13 mLAdditional dosage information:15 X = 1.95 mg.

Documentation for Practice Problem 2

Sample entry for documentations:

S: BAR
O: 200g
PE-NR
P: Performed brief PE. Administered 1.95 mg (0.13 mL) Sleepystuff IP lower right abdomen.

P. Carr