Routes of Administration

Question 1

Entral Administration

Answer 1

Involves the GI tract and includes oral, buccal and rectal

Question 2

Parenteral Administration

Answer 2

Does not involve the GI tract, injections, topical and inhaled administrations

Question 3

What does the route of administration depend on? (4)

Answer 3

The properties of the active drug, the disease state to be treated, the temperate and condition of the patient, the confidence and ability of the owner to adminsister the medication

Question 4

Oral route
Advantages and Disadvantages

Answer 4

A- Variety of forms available - Solid or Liquid
Generally easy for the owner to administer at home

D- Not suitable for vomiting, seizuring or unconsious patients
Food can affect the absorption of some drugs and absorption from the GI tract may be irregular
Some drugs destroyed by enzymes in the GI tract

Question 5

Buccal and sublingual
Advantages and Disadvantages

Answer 5

A- Quick onset of action
can be administered to unconscious or vomiting patients as medication is not being swallowed
Drugs are absorbed directly into the systemic circulation therfore avoiding first pass metabolism

D- Few drugs are available in formulations suitable for buccal and sublingual absorption
Variabliluty in absorption between soecies - Bupernorphine is well absorbed in cats but not in dogs

Question 6

Rectal
Advantages and Disadvantages

Answer 6

A- Can be used when the oral route is innapropriate - diazepam for a seizuring patient
Useful when the drug causes GI tract irratation

D- Absorption can be irregular and unpredictable, leading to a variable effect
Less convenient than the oral route and low owner acceptability for home use

Question 7

Topical
Advantages and Disadvantages

Answer 7

A- easy to apply & non invasive
application can be ttargeted to the exact site it is required
long term use possible

D- Slow absorption
Most drugs have a high molecular weight and are poorly lipid-soluble, so are not absorbed via the skin or mucous membranes
Animal may interfere with preparation once applied - lick, chew scratch

Question 8

Inhalation
Advantages and Disadvantages

Answer 8

A- Fast absorption and onset of action
No first pass metabolism, does can be lower than with the oral route with a consequent reduction in side effects

D- Administration can be difficult in animals that do not tolerate a spacer device well
Nebulisers are expensive

Question 9

Intra-articular Injection
Advantages and Disadvantages

Answer 9

A- Accurate and exact does possible - able to administer amount calculated and full amount will be able to have an effect
Rapid onset of effect - not required to be absorbed and distributed around the body
Localised effect - higher doses can increase effectiveness of the drug

D- Painful procedure - Sedation/GA required
Sterility required - prep of site, sterile gloves
Needs to be performed by a vet
High risk of infection

Question 10

Intramusclular injection
Advantages and Disadvantages

Answer 10

A - Drugs are absorbed more quickly and consistently than with sub/cut route - muscle has a much richer blood supply than sub/cut fat
Accurate dose possible able to administer the amount calculated and all of it will be able to have an effect

D- Only small volumes can be adminstered as muscle tissue is densly packed
Painful injection
Skill required - not to hit sciatic nerve
Risk of infection, Injury and Assistance

Question 11

Intra-osseous Injection
Advantages & Disadvantages

Answer 11

A - Rapid action, almost dirrect effect due to massive blood supply to the bone
Accurate and exact dose possible able to administer the amount calculated and all of it will be able to have an effect

D- Sedation/GA required as this is a painful procedure
Sterility required - prep of site, hair needs cliped and sterile gloves
High risk of infection as injecting into the bone

Question 12

Intravenous Injection
Advantages and Disadvantages

Answer 12

A- Most rapid action achieved by I/V injection - almost immediate depending on animals circulation and direct effect
Large volumes can be given over time intraveoune fluid therapy (IVFT)

D- Assistance & skill/training required
Preparation of skin
care to ensure correct dose
Increased risk of infection

Question 13

Intraperitoneal Injection
Advantages and Disadvantages

Answer 13

A- Relatively rapid effect as peritoneal cavity has excellent blood supply
Relatively painless method and relatively large volumes can be administered

D- Assistance, Skill - confident not to hit any organs as risk of penatratiing orfan
Risk of infection and injury

Question 14

Administration of intra-articular injection

Answer 14

Medication given directly into the joint, needle inserted into the joint cavity
used for adminsitration of long lasting analgesics/ anti-inflammatorroes for joint conditions

Commonly used in horses - less so in small animals

Question 15

Administration of Intra-muscular injection

Answer 15

Medicine injected into muscle sites - quadricepts femoris, lumbar muscles used - in cats seems less painful. Gluteal not often use as risk of hitting sciatic nerve

Hold muscle mass with one hand, insert needle 3/4 of it’s length
Before injecting drug, draw back plunger to check for blood.
Blood indicates hitting a vesselk and the preparation may not be suitable for I/V administation so remove needle and redirect.

Question 16

Administration of Inra-osseous Injection

Answer 16

Medication injected directly into the bone, needle is inserted into the medullary cavity of the bone. The femoral head, humerus and wing of illium are commonly used

Generally used when i/v access is not possible or a rapid response to medication is required e.g. neonates, small furries, birds, reptiles, severe shock and another route would take to long to have an effect.

Hypodermic needle used in very small/ small animals

Question 17

Administration of Oral medication

Answer 17

Drug is administered via the mouth.

Passes into the stomach (where it may be dissolved), then passes into the small intestines where it is absorbed into the bloodstream. It is then transported / distributed throughout the body.

Oral medications can take the form of liquids, tablet, capsule, powders or granules and can be administered by hand, in food, via syringe or via a tube.

Care to ensure oral meds are not aspirated by mistake (this is more commonly a complication with oral administration of liquids, especially if the animal struggles during administration or if the animal is recumbent).

Question 18

Administration of Subcutaneous Injection

Answer 18

Medication injectied into the fat layer which lies under the skin.
Scruff at the back of the neck is the most commonly used site, along with other areas of loose skin

Skin is grasped with one hand and needle inserted ¾ of its length at 45 angle to the skin. Before injecting the drug, draw back plunger to check for blood.

Blood indicates that you have hit a vessel and as the preparation may not be suitable for intravenous administration the needle should be removed and re-directed.

Question 19

Administration of Intraveous injection

Answer 19

Medication is injected directly into a vein.

The cephalic vein is most commonly used as it is easy to access. The saphenous vein and jugular vein can be used although these are generally only used if the cephalic is not possible.
The marginal ear vein is commonly used in RABBITS

The needle is inserted into the vein and the plunger drawn back to ensure blood is present before injecting.

It is important to make sure that the needle is in the vein before injecting as some medications can cause severe damage to surrounding tissue. It will also take longer for the drug to have its desired effect if it is not given directly into the vein.

Question 20

Administration of Intraperitoneal Injection

Answer 20

Medication is injected into the peritoneal cavity

The animal is held on its back with its head held downwards, allowing abdominal organs to move towards the diaphragm (reducing the risk of injecting into an organ). The needle is inserted at 20 angle into the abdomen, lateral/caudal to the umbilicus (lower right) directed towards the head.

Before injecting the drug, draw back plunger of syringe to check for fluid. Fluid indicates that you have hit an organ therefore the needle should be removed and a fresh needle/syringe with newly drawn up preparation should be administered otherwise you will contaminate the abdomen.

This route is mainly used in rodents as i/v access is difficult.

Question 21

Topical administration

Answer 21

This is when the medication is applied directly/locally to the desired area. The drug only has an affect on the area it is applied to as it is not absorbed into blood stream.

Creams, ointments, lotions, shampoos, powders, drops, gels, aerosol sprays, inhalants are commonly used as topical preparations

Question 22

Most common parenteral routs (4)

Answer 22

Subcutaneous, Intramuscular, Intravenous and Intraperitoneal

Question 23

Lesss common parenteral routes include (3)

Answer 23

Intraosseous, Intra-articular, Epidural