Administration of medicines in animals

Different means of administration of medicines to animals.and their advantages and disadvantages.

1. Veterinary Clinical medicine
ADMINISTRATION OF
MEDICATIONS
SHARON A .J
2009-03-10

2. Drug Routes
Drugs may be administered in various ways.
The route chosen depends on the part of the
body the drug needs to affect, how quickly
the drug needs to work, and the ability of the
owner to give the drug.

3. Routes of administration
Oral
Parenteral
IV IM IP IC SC
Other
Topical
Rectal
Intrauterine
Intramammary

4. Advantages of Oral
medication
Usually least painful
Can be administered by client
Skin not penetrated, less risk of introducing infection

5. Disadvantages of Oral medication
Aspiration of medication - choking,
pneumonia (eg paraffin to cats)
Variable rate of absorption depending on
patient, contents of gut, etc.
Vomiting, irritation of gut (eg aspirin)
Patients may not tolerate administration
May be difficult to ensure correct dosage

6. Oral medications
Tablet
Capsule
Granule
Powder
Paste
Liquid

7. Tablet
Compressed drug in a carrier such as chalk
or sugar
Often coated
to protect drug inside from moisture
to disguise unpleasant tastes
to protect from gastric juices, slow down the breakdown
of the drug for a slower release
to avoid irritation
to give the tablet a recognizable colour
Usually scored into halves or quarters for
ease of breakage for more accurate dosing
Most common form of medication

8. Tablet Administration

10. Capsule
Bullet-shaped, gelatin container
Contains powder, granules or liquid
Easier to swallow (smooth)
No need for 'carrier'
Gelatin dissolves in stomach

11. Granules/Powder
Solid preparations
Dissolved in water
eg Vytrate
®
,

Lectade
®
Mixed with feed

12. Paste
Semi solid preparation
Usually in a water soluble base
Via syringe
Easy for owner to use
Rabbit, guinea pig
Horse (worming paste)
Cat (worming paste)

13. Liquid
Syrup
Drugs contained in a concentrated sugar solution. 
Good for young animals/small doses (eg Clavulox drops).
Solution
Drug in liquid form or dissolved in water (eg glucose solution).
Suspension
Insoluble particles float in liquid but settle when standing
Needs to be mixed before use (shaken)
Emulsion
Two immiscible liquids (eg water and paraffin).

14. Routes of enteral liquids
Directly into the mouth
By crop needle (birds)
By stomach tube
Drugs which burn the mouth
Very young animals, to reduce the risk of
aspiration
Large volumes of fluid.

15. Parenteral Preparations
These are drugs that can be given by injection. All
drugs in this form must be sterile. The most common
routes of injection of drugs in small animal practice
are iv ,im,ip,sc,ic
Usually taken to mean ‘by injection’
Strictly, par-enteral = ‘adjacent the gut’

16. Injection Route depends on
Type of drug
Condition and temperament of patient
Volume of the drug,
Required speed of action

17. Systemic Drugs
Some drugs cannot be applied directly where
they are needed. Instead they need to travel
through the animal’s system until they get to
where they are needed. These drugs are said
to be given SYSTEMICALLY.
Examples include oral preparations and
injections

18. Routes of injection
Intradermal
Intramuscular
Intravenous
Intraperitoneal
Intracardiac
Intrapleural
Intra-articular
Epidural
Subconjunctival

20. Intradermal (ID)
Into the dermis
The living part of the surface layer
Needs a very fine needle
Causes a blister like appearance (bleb) if
performed correctly
allergy testing
tuberculin testing

21. Subcutaneous (SC)
Under the skin
Most common site
Loose skin over shoulder blades a
good site
Less painful than intramuscular
injections
Only for low irritant drugs
Slow absorption if dehydrated
Used for most vaccines

22. Intramuscular
Injected deep into the body of a
muscle
Less likely to cause an overt tissue
reaction
Insert needle at right angles to the
skin
Larger volumes may be injected in
the one site than with other routes
Faster absorption than s/c

23. Im sites

24. Intravenous (IV)
Into the vein directly
Fastest onset of action
Can give irritant solutions into the vein which
cannot be given IM or SC     
Irritant drugs should be given via an
intravenous catheter, (caparsolate,
thiopentone, guifenasin)

25. Peri-vascular Necrosis
When irritant solution leaks from a vein
and enters
area may 'slough‘
Immediately inject the area with
saline (isotonic i.e. 0.9% NaCl) to
dilute the drug  

26. Intra-peritoneal (IP)
Into peritoneal cavity
Usually near umbilicus
Or half way between umbilicus &
pubis
Used for
Rodents
Birds
Euthanasia of young difficult patients

27. Intra-cardiac (IC)
Injection through the chest wall into the
heart
Emergency administration of drugs
during cardiac resuscitation
e.g. adrenaline
Euthanasia
Moribund animals

29. Intrapleural
Injection into the pleural space through
the chest wall
Not commonly used

30. Intra-articular
Injection into the joint space
Needs full surgical preparation
should also wear gloves and draw drug up
in a sterile manner, new unused bottle, etc,
to avoid introduction of infection.
Used for
Dogs (eg cortisone with greyhounds,
Cartrophen)

31. Epidural
Injection into the epidural space surrounding
the spinal cord usually in the lumbar site
Full sterile prep needed
Animal positioned on sternum, with back
legs drawn forwards
Used for
Before an orthopaedic procedure on spine
or hindquarters
Pain relief (eg morphine, local anaesthetic
for dog)
Stops straining and gives pain relief,
(lignocaine, xylazine).

32. Epidural site

33. Subconjunctival
Into the conjunctiva of the eye
Use a fine needle
Needs good restraint
Used for
Ocular conditions

34. Safety Considerations
Wear all
proper PPE
for the
procedure.

35. Supplies Needed
Before giving an injection, gather the following:
The drug or substance to be injected.
Alcohol swab or alcohol moistened cotton
ball
Correct size syringe
Correct size needle
Sharps Container- a hard plastic with a screw-
on or tightly-secured lid

36. Factors to Consider
When choosing needle size, syringe size, and injection
site / route of injection there are several factors which
need to be considered:
The type of the solution / medication.
The viscosity (Thin / watery? Thick / sticky?)
The absorption rate for the solution / medication.
The size of the patient (Beagle? Hound? Something larger?)
The mobility status of the patient (Anesthetized? Immobile?
Fully conscious?

37. Venipuncture
The cephalic vein on the inside of the front
limb below the elbow may be used.

38. Hold off the vein by gripping
and rolling laterally

39. .
Prepare the site
Clip area
Wipe with alcohol

40. Insert needle,
bevel up, into
the vein.
Gently pull
back.
Hold off when
completed.

41. Medial saphenous vein on the
hind limb can also be used.

42. Factors to Consider: IM
Injections
Intramuscular injections may be performed
in the thigh muscles on the front of the
rear limb, or using the hamstring muscles on
the back side of the rear leg
If blood is aspirated, the needle should be
removed as this indicates needle placement
in a blood vessel. Reinsert the needle at a
different site.
Needle sizes used for IM injections range
from 25 to 20 gauge. Muscle is dense tissue
and can only accommodate small volumes of
fluid

43. Triceps muscle
The triceps muscle belly located caudal to
the humerus is one IM injection site. The
left thumb is placed on the humerus,
isolating the muscle belly in the left hand.
The needle is placed in the muscle belly.
The plunger is withdrawn to create
negative pressure.

44. Quadriceps muscle
The quadriceps muscle is located
anterior to the femur. The left
thumb is on the femur. The needle
is inserted at a right angle to the
muscle belly.

45. Semitendinosis muscle
Administering an injection into the
semimembranous/semitendinosis muscle
group, the tip of the needle (white arrow)
should be directed toward the caudal
aspect of the limb so if the patient moves,
the needle will not advance toward the
sciatic nerve. Notice the left hand is being
used to isolate the muscle group caudel to
the femur.

46. Lumbar muscle
The dorsal lumbar muscles on
either side of the midline can be
used for IM injections. The thumb
of the left hand is on the transverse
processes of the lumbar vertebrae.

47. Factors to Consider: SC
Injections
For SQ (subcutaneous) injections, in general, use :
An 18 or 20 gauge needle, 1 to 1.5 inches long.
SQ medications are deposited into the loose connective
tissue just below the dermis.
This tissue is not richly supplied with blood vessels so the
absorption rate is slow.
There are many pain receptors in this tissue so only non-
irritating, water-soluble medications in small doses should
be given by the SQ route.

48. The loose skin over the
shoulders and neck is an
ideal site for
subcutaneous injection . 

49. Procedure for sc injection

50. Topical medications
External surfaces
eg the skin, eyes, ears
Exposed mucous membranes
eg gums, nasal mucosa, prepuce and
penis, vulva and vagina.
Medication may work
Topically - on only the area to which it is
applied
(eg ringworm ointment)
Systemically (eg Spotton, Ivomec Pour On,
DMSO)  

51. Cream
CREAMS – the drug is dissolved in water and mixed
with oil or fat. Creams spread easily and penetrate
the outer layers of the skin
A semi-solid water-soluble emulsion which
penetrates the skin surface
Tubes or plastic squeeze bottles
Wash off with water.

52. Ointment
OINTMENTS – the drugs are present in a base of wax
or fat. They do not penetrate the skin.
Semi-solid oil-based preparation, usually with a base
of wax or jelly
Comes in tubes, jars, etc.
Does not usually get absorbed by the skin, (eg
prednoderm).

53. Suspension
Liquid preparation in which particles suspended in
the liquid
Will separate out on standing, so needs to be
shaken, (eg calamine lotion, yellow lotion)

54. Rinse/Wash/Solution
Liquid which often diluted and poured on an animal
May have a residual action when dry, (asuntol,
otoderm, ectodex).

55. Aerosol
SPRAYS – a way of applying liquids in fine droplet
form
Liquid under pressure
Sprayed on as particles of liquid suspended in air,
(eg chloromide, debrisol, frontline, fly repellent)

56. Powder
Finely particulate solid preparation which dusted on
Can be irritant to open wounds
May help to dry weeping wounds, (eg tricin powder,
pinkeye powder)

57. MEDICATED SHAMPOOS
MEDICATED SHAMPOOS – drugs mixed with
detergents which penetrate the coat. Shampoos
are left in contact with the skin for the
recommended amount of time and then should be
rinsed off thoroughly.

58. EYE & EAR MEDICATION
EYE & EAR MEDICATIONS – these are both examples
of topical medication.
Eye medications should be sterile. Once they have
been opened they should be stored only for the
length of time recommended by the manufacturer.

59. Aural medications
Drops or Ointments
The ear is ideally cleaned of wax and
discharge before administration of
medication

60. Medications per rectum
Enema
Suppository
Fluid replacement

61. Enema
Commercial solutions
Syringe, tube or pack (eg Microlax
®
)
Soapy water
Funnel and tubing
Other substances
paraffin, bloat treatment (Tympanyl
®)
)

62. Suppository
Bullet shaped, semi solid, glycerine based
Melts at body temperature
Can contain antibiotics, laxatives, soothing agents
May be absorbed systemically

63. Medications intra-uterine
Pessaries
Solutions

64. Pessaries
Large tablets
Usually antibiotic
May also have a foaming agent
Administered by hand when the cervix is open for
example, after a calving

65. Intra-uterine fluids
Administered via the cervix with a pipette or balloon
(Foley) catheter
During oestrus when the cervix is relaxed
Some will remain in the uterus, while others will be
siphoned out again

66. Health & Safety and
Administering Medicines
Health and safety should be considered in order to
make sure that we don’t get hurt whilst
administering medicines.
It is also important to ensure that the animal doesn’t
get hurt or frightened.

67. What are the risks to animals
when administering
medicines?
Overdose
Allergic reaction
Wrong administration route selected
Animal stressed
Animal gets injured

68. How can these risks be
minimised
Follow instructions carefully
Make sure that the animal is adequately restrained
Use sprays in a well ventilated area
Wear appropriate PPEs (e.g. gloves, mask etc)