Veterinary Maths and Therapeutics

Question 1

How to convert ug to mg?

Answer 1

/ 1000

Question 2

How to convert mg to ug?

Answer 2

x 1000

Question 3

What do you need to calculate when doing drug dosage? (3)

Answer 3

1. How many mg or ug are needed
2. How many mg or ug per ml for the particular drug?
3. Do I need more or less than one ml?

Question 4

Each drug has different….

Answer 4

mg per ml

Question 5

What calculations do you need to be able to do in veterinary maths?

Answer 5

1. Fractions to decimals
2. Multiply whole numbers by fractions
3. Add fractions
4. Do simple proportions
5. Take a percentage of a number

Question 6

A 44 kg diabetic dog needs 0.25 U/kg insulin
- Insulin comes as a 100 U/ml
solution
Q1. How many units do I need?
Q2. How many units in one ml?
Q3. Do I need more or less than one ml?
Q4. How many ml will I inject?

Answer 6

1. No. of Units = 0.25 U/kg X 44 kg = 11 Units
2. 100 Units/ml
3. Less than a ml
4. Number of mls = 11 Units ÷ 100 Units/ml
   = 0.11 ml

Question 7

A 600 kg Friesian cow is to be sedated prior to anaesthesia and needs 0.15mg/kg xylazine.
- Sedative xylazine is 20 mg/ml
Q1. How many mg do I need?
Q2. How many units in one ml?
Q3. Do I need more or less than one ml?
Q4. How many ml will I inject?

Answer 7

1. 600 kg X 0.15mg/kg = 90mg
2. 20 mg/ml
3. More than a ml
4. 90mg/20mg/ml = 4.5ml

Question 8

How can we minimise calculation mistakes? (4)

Answer 8

1. Do the calculation with a pen and paper (or on you phone or in your head)
2. Repeat the calculation using your calculator
3. Look at the answer and consider whether it ‘looks right’
4. Ask someone else to check

Question 9

ug =

Answer 9

microgram

Question 10

mg =

Answer 10

miligram

Question 11

ml =

Answer 11

mililitre

Question 12

What is therapeutics?

Answer 12

Treatment and care of a patient for the purpose of both preventing and combating disease or alleviating pain or injury

Question 13

What is pharmacology?

Answer 13

The study of drugs

Question 14

What is pharmacodynamics

Answer 14

What the drug does to the body (eg sedative, change heart rate etc)

Question 15

What is pharmacokinetics

Answer 15

What the body does to the drug (elimination, metabolism etc)
- How long does it last?
- How fast does it have an effect?

Question 16

Pathogenesis

Answer 16

What’s causing this disease or symptom

Question 17

MOA=

Answer 17

Mode of action (of a drug)

Question 18

Correct drug doses are crucial to ___ and ___

Answer 18

safety; effectiveness

Question 19

What do you need to know before you administer a drug?

Answer 19

• Mode of action (MOA)
• Route of administration
• Speed of onset
• Duration of action
• How often should we dose?
• Will the drug accumulate with repeated doses?
• If so, reduce the dose or lengthen the dosing interval

Question 20

SID, OID, q24h

Answer 20

Once daily/every 24 hours

Question 21

BID, q12h

Answer 21

Twice daily/every 12 hours

Question 22

TID, q8h

Answer 22

Three times daily/every 8 hours

Question 23

QID

Answer 23

Four times daily

Question 24

PRN

Answer 24

As needed

Question 25

qxh, qxd

Answer 25

Every x h, every x days

Question 26

Ad lib

Answer 26

Freely as wanted

Question 27

A patient weighing 19kg requires a drug with a dose rate of 12.5mg/kg BID for 7 days. The tablet size is 500mg. Q1. How many mg does the patient require per dose? Q2. How many tablets per dose? Q3. How many tablets to dispense?

Answer 27

1. 19 x 12.5 = 237.5mg 2. 237.5/500 = 0.475 = 0.5 (rounded up) 3. 0.5 x 2 = 1 tablet per day 7 x 1 = 7 tablets

Question 28

Rounding in dose calculations:

Answer 28

Round as **late as possible** in the process (2 decimal places!) - do the maths backwards to check how much you are adding or subtracting from the dose per kg

Question 29

A patient weighing 5kg requires fluid therapy at a rate of 5ml/kg/hr. Q1. How many mls does the patient require per hour? Q2. How many drops per second do we need if 1ml is delivered in 60 drops?

Answer 29

1. 5 x 5 = 25mls 2. Calculate how many mls need to be delivered per minute to achieve this. - 0.4ml every minute 24 drops over 1 minute (0.4 x 60 drops) - 24/60sec = 0.4 drop per second (round up to 0.5) = 1 drop per 2 seconds (1/0.5) (2 s per drop)

Question 30

I am speying a 22.8kg dog and want to administer IV fluids - The recommended rate is 5mls/kg/hour Q1. How many mls per hour should you administer? Q2. How many drops per ml from your giving set? Q3. How many drops per hour? Q4. How many drops per minute? Q5. How many drops per second or interval between drops?

Answer 30

1. 22.8 x 5 = 114 mls per hour 2. Standard is 20 drops per ml 3. 114 x 20 = 2280 4. 2280 / 60 = 38 5. 38/ 60 = 0.63 drops/sec = 1 drop every 1.5 seconds (1/0.63) OR: = 6 drops every 10 seconds = 3 drops every 5 seconds