Drug Doses and Injection Techniques

Question 1

Why is the correct drug dosage essential

Answer 1

1. Too low a dose and the drug won’t reach therapeutic levels = ineffective
2. Too high = dangerous and potentially life threatening

Question 2

What is therapeutic dose of a drug

Answer 2

The amount needed to treat a disease

Question 3

What are the different ways of drug administration

Answer 3

1. Topical
2. Enteral
3. Parenteral

Question 4

What is Topical?

Answer 4

1. applied to a particular site
2. May include
   a) epi cutaneous (application to skin) e.g. dermatological preparations
   b) Inhalational e/g/ asthma inhalers
   c) Enema (absorption via rectal mucosa (some anti seizure medications)

Question 5

What is Enteral

Answer 5

1. Administration via GI
2. May include:
   a) Oral/ Gastric e.g. tablets or oral liquids
   b) Rectal (considered the same as topical enema preparations) e.g. some anti seizure medications

Question 6

What is parenteral

Answer 6

1. Non oral, systemic administration
2. generally considered to be injection
3. may include:
   a) subcutaneous (under skin)
   b) Intramuscular (into muscle)
   c) Intravenous ( into vein)
   d) Intradermal (into layers of skin)
   e) Intracardiac (into heart)

Question 7

What are the most common routes for parenteral injection

Answer 7

1. subcutaneous: slowest absorption
2. intramuscular
3. intravenous: fastest absorption

Question 8

To calculate the dose of an Enteral medication what do we need to know?
Then how do you calculate the required number of tablets?

Answer 8

ORAL
1. Weight of the patient in kilograms (kg)
2. Dose rate usually in milligrams per kilogram (mg/kg)
3. Drug concentration usually in milligrams per tablet (mg/tablet)
CALCULATION:
Number of tablets = Weight of animal (kg) x Dose rate (mg/kg) /
Drug concentration (mg/tablet)

Question 9

How do you calculate the appropriate dose of parenteral medication and calcualtion

Answer 9

1. Weight of the patient in kilograms (kg)
2. Dose rate usually in milligrams per kilogram (mg/kg)
3. Drug concentration usually in milligrams per millilitre (mg/ml)
   CALCULATION:

Volume of drug (ml) = Weight of animal (kg) x Dose rate (mg/kg) /
 Drug concentration (mg/ml)

Question 10

How are parenteral medication presented

Answer 10

in 2 forms

1. Solution, a soluble substance dissolved in a solvent
2. Suspension, an insoluble substance suspended in a solvent

Question 11

What do you need to remember when usign a suspension medication

Answer 11

1. Insoluble substance may settle out over time so must shake vigorously to ensure even dispersion and NEVER intravenously

Question 12

What is the prescribing cascade

Answer 12

1. specific guidelines which must be followed when considering which medication to use

Question 13

Why best to use a veterinary medicine that has been authorised in the UK for treatment of the condition in the species you are treating?

Answer 13

Because the medication will have been tested for appropriate safety, quality and efficacy (ability to produce a desired or intended result.)

Question 14

If there is no suitable medication authorised for this use in the UK what must you follow when selecting medication?

Answer 14

1. A veterinary medicine authorised in the UK for use in another animal species, OR for a
   different condition in the same species
2. A medicine authorised in the UK for human use, OR a medicine authorised in animals in
   another EU member state
3. Medicine made up at the time on a one-off basis by a veterinary surgeon or a properly
   authorised person

Question 15

What checks must you undertake before you administer medication?

Answer 15

1. Do you have the right patient?
2. Have you selected the right drug?
3. Have you calculated the right dose?
4. Have you checked you are administering the medication via the right route?
5. Are you giving the medication at the right time?
6. Is the medication being administered at the right frequency?

Question 16

What is the formula used when calculating the volume to be injected?

Answer 16

Patient weight [kg] x dosage [mg/kg] /

concentration [mg/ml]

Question 17

If the drug dosage is expressed as ml/kg how do you calculate the volume?

Answer 17

Dosage [ml/kg] x patient weight [kg]

Question 18

What do you need to do before take drug

Answer 18

1. swab the top of the drug bottle as the rubber seal can get dirty = could be drawn up into the syringe

Question 19

Once got the correct volume of medication then what

Answer 19

1. DEtach the needle from the syringe and replace with a new one of appropriate length adn gauge as ensures it is sharp so less painful for animal and sterile

Question 20

How do you carry out a subcutaneous injection?

Answer 20

WASH HANDS

1. injected under skin usually in dorsal cervical area (scruff)
2. restrained in sternal recumbency, sitting or standing
3. Draw up accurate dose
4. swab injection site with skin disinfectant to remove debris
5. Pick up fold of skin by pinching between thumb and finger
6. insert needle subcutaneously up to hub
7. observe the needle hub for blood
8. connect syringe to needle hub
9. inject in moderate controlled fasion
10. remove needel adn syringe and massage

Question 21

When inserting needle if resistance is felt what does this mean and what should you do

Answer 21

1. it is being inserted intradermally or intramuscularly so should be redirected

Question 22

Why should you observe the needle hub for blood

Answer 22

1. ensures the agent isn’t being injected intravascularly as some agents can cause a severe reaction and/ or death if intravascularly

Question 23

Why massage the site

Answer 23

to ensure dispersal of agent and helps alleviate irritation

Question 24

Where to inject intramuscular on canine and horse

Answer 24

canine = quads, lumbo dorsal muscles (either side of lumbar vertebrae) or triceps.
equine = superficial pectorals, lateral neck, gluteals, semimembranosus and semitendinous

Question 25

What msucle to avoid when injecting intramuscular on dog

Answer 25

HAMSTRING because risk of sciatic nerve damage

Question 26

How to inject intramuscularly

Answer 26

1. identify site for intramuscular injection 2. restrain patient appropriately 3. Clean hands 4. prepare injection (draw up accurate dose) 5. Observe needle hub for blood - ensure not intravascularly 6. connect syringe 7. inject material in moderate controlled fashion 8. remove needle

Question 27

What do you need to remmeber about injecting into muscle

Answer 27

1. muscle is dense and cannot accomodate large volumes of liquid 2. 2ml in a cat 3. 3-5 ml in a dog 4. 10 mls in equine neck, 20-30 in pectorals gluteals)

Question 28

How to take a intravenous injection/ taking blood

Answer 28

1. ask assistant to raise vein 2. clean hadns 3. Swab injection site with disinfectant 4. Identify vein by palpation adn stabilise it by placing thumb of free hand along it 5. hold needle with bevel facing up and insert through skin and into raised vein at approx 30 deg to skin up to half needle length 6. dark venous blood drips from needle 7. advance needle along vein up to hub 8. inject stuff 9. remove needle and syringe and apply swab under pressure to injection site

Question 29

Where can intravenous injections be injected

Answer 29

1. Jugular, cephalic, lateral saphenous or femoral vein

Question 30

What position should the patient be in when taking blood from jugular

Answer 30

1. Sternal or lateral recumbency, limbs forward, head turned away from injector, injector responsible for raising vein

Question 31

What position should patient be in when taking blood from cephalic vein?

Answer 31

Sitting or sternal recumbency, limb held forward with restrainer’s hand behind elbow and thumb used to raise the vein. Vein raised by injector just above elbow using rubber band and secured tight with artery forceps

Question 32

How do you know if you have inserted the needle correctly when intravenous

Answer 32

1. Dark venous blood should drip from hub if the needle has successfully entered a vein. 2. bright red blood exits under pressure = inadvertently = entered an artery = very dangerous. Apply pressure above the insertion site, withdraw needle, start again.