This document discusses pain management and analgesia. It covers the physiology of pain, classification of pain types, the pain pathway in nociception, consequences of untreated pain, types of hyperalgesia, physiologic changes caused by pain, signs of pain in animals, tools for pain assessment, effective postoperative analgesia, and various opioid and non-opioid agents used for pharmacologic pain management. The focus is on controlling pain at different stages including preoperative, surgical, postoperative, and at home periods using multimodal therapy and a variety of analgesic drugs and techniques.

1. 1Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Controlling Pain
Analgesia
Chapter 7

2. 2Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Physiology of Pain
 Nociception: detection by the nervous system
for the potential for, or actual tissue injury
 Protects animal from painful or noxious stimuli
 Physiologic pain
 Ouch pain
 Little or no tissue injury
 Pathologic pain
 Follows tissue injury
 Acute or chronic

3. 3Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pathologic Pain
 Classification based on mechanism
 Inflammatory, neuropathic, cancer, idiopathic
 Classification based on origin
 Visceral or somatic: superficial or deep
 Classification based on severity of pain
 None, mild, moderate, severe

4. 4Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Nociception: The Pain Pathway
 Step 1: transduction
 Transformation of stimuli into sensory electrical
signals (action potentials)
 Step 2: transmission
 Sensory impulses conducted to spinal cord
 Step 3: modulation
 Impulses are either amplified or suppressed
 Step 4: perception
 Impulses are transmitted to the brain where they
are processed and recognized

5. 5Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Nociception: The Pain Pathway
(Cont’d)
 Each step has different receptors
 Drugs can be selected that will target specific
receptors and block a specific step
 Multimodal therapy: targeting two or more of the
receptors

6. 6Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Consequences of Untreated Pain
 Catabolism and wasting
 Immune system suppression
 Inflammation and delayed wound healing
 Anesthetic risk and increased anesthesia
doses
 Patient suffering

7. 7Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Primary Hyperalgesia
 Peripheral hypersensitivity
 Results from tissue damage and constant
stimulation of nerves
 Area close to the site of tissue injury
becomes painful when stimulated with non-
noxious stimuli

8. 8Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Secondary Hyperalgesia
 Central nervous system hypersensitivity or
windup
 Area of hypersensitivity is further away from
the site of tissue injury
 Results from constant stimulation of spinal
cord neurons
 Neurons become hyperexcitable and
sensitive

9. 9Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Physiologic Changes
Caused by Pain
 Neuroendocrine changes: can result in a
catabolic state and wasting
 ACTH release
 Elevated cortisol, norepinephrine, and epinephrine
 Decreased insulin
 Sympathetic stimulation: can result in cardiac
arrhythmias
 Vasoconstriction
 Increased myocardial work
 Increased myocardial oxygen consumption

10. 10Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Signs of Pain in Animals
 Pain elicits a stress response
 Stress-related pain results in “fight-or-flight”
physiological response
 Avoid anthropomorphosis

11. 11Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Preemptive Analgesia
 Administration of pain medication before the
pain occurs
 Commonly involves adding analgesic to
premedication prior to anesthesia
 Reduces overall requirement for analgesia
and duration of administration
 Prevents windup

12. 12Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Behavioral Responses to Pain
 Vary depending on species, age, breed, and
temperament
 Young patients less tolerant
 Cattle very stoic
 Large dog breeds more stoic than small toy
breeds
 Cats hide; dogs seek owner comfort; herd animals
separate themselves
 Vary depending on nature, duration, and
severity of pain
 Vary on the presence or absence of humans

13. 13Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Physical Evidence of Pain
 Changes in gait and level of activity
 Evidence of arthritic pain
 Reluctance to lie down or constantly shifting
position
 Evidence of thoracic or abdominal pain

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Physical Evidence of Pain (Cont’d)
 Vocalization
 Whine, growl, whimper, groan, snarl, bite, hiss,
grunt, or purr
 Emergence delirium
• Immediate postoperative vocalization
 Changes in facial expressions, appearance,
and attitude

15. 15Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pain Assessment Tools
 Verbal rating scales
 Simple descriptive scales
 Numeric rating scales
 Visual analogue scales
 Comprehensive scales

16. 16Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pain Assessment Tools: Verbal Rating
Scales and Simple Descriptive Scales

17. 17Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pain Assessment Tools:
Numeric Rating Scales

18. 18Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pain Assessment Tools:
Visual Analogue Scales

19. 19Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pain Assessment Tools:
Comprehensive Scales

20. 20Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Assessing Response to Therapy
 Acute surgical pain vs. chronic pain
 Hourly vs. monthly
 With effective analgesia, pain-associated
behaviors will recede
 Appetite, grooming, body position or posture,
interaction with people
 With effective analgesia, pain assessment
scores will decrease

21. 21Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Effective Postoperative Analgesia

22. 22Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Perioperative Pain Management
 Preemptive analgesia
 Begins in preoperative period with premedication
 May be administered as part of anesthetic
premedication
 Transdermal fentanyl patch
 NSAIDs primarily in large animals
 Multimodal therapy
 The use of more than one drug to control pain
 Cover multiple receptors and mechanisms of
action
 Reduce dose of individual drugs and anesthetic
agent

23. 23Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pharmacologic Analgesic Therapy
 Analgesia is needed at every stage of
hospitalization and treatment
 Preanesthetic period
 Surgical period
 Immediately postoperative period
 Remainder of hospital stay
 At home

24. 24Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Pharmacologic Analgesic Therapy
(Cont’d)
 Choice of drug depends on:
 Severity and type of pain
 Patient’s general condition
 Route of delivery

25. 25Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Using Opioids as Analgesics
 Vary in potency, duration, and adverse effects
 Injectable premedication
 Often in combination with a tranquilizer
(acepromazine or dexmedetomidine)
 Diminish windup
 Duration of action is 2-4 hours, so not good for
postoperative pain
 Induce state of potent sedation
 Neuroleptanalgesia
 Provides analgesia throughout surgery and for
some time postoperatively

26. 26Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Using Opioids as Analgesics (Cont’d)
 Postoperative analgesia
 Alone or in combination with other drugs
 Sedative and antianxiety drug
 Excitement in awake cats and horses
 Gastrointestinal effects
 Initial increased gastrointestinal activity: nausea,
vomiting, defecation
 Followed by a slow down in gastrointestinal
activity: ileus, colic, constipation
 Metabolized in the liver

27. 27Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Morphine
 Schedule II drug (United States) and narcotic
(Canada)
 Used for moderate to severe visceral or
somatic pain
 Preanesthetic and analgesic
 Pure agonist with affinity for mu and kappa opioid
receptors
 May cause excitement or dysphoria in cats and
horses
 May cause restlessness in dogs and horses

28. 28Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Morphine (Cont’d)
 Administered IV, IM, SC, intraarticular,
epidural, or spinal injection
 Adverse side effects
 Initial gastrointestinal stimulation in dogs and cats
 Ileus and colic development in horses
 Excitement, miosis (dogs), mydriasis (cats),
hypothermia, hyperthermia (cats)
 Bradycardia, panting, increased intraocular
pressure, urinary retention
 Physical addiction (humans)

29. 29Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Oxymorphone
 Pure opioid agonist
 Greater analgesic potency and sedative effect
than morphine
 Fewer side effects and longer duration of
effect than morphine
 Fewer tendencies to induce vomiting
 Administered IV, IM, SC, or epidural
 May use concurrently with a tranquilizer
 Expensive Schedule II drug (United States)
and narcotic (Canada)

30. 30Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Hydromorphone
 Opioid agonist
 Less potency but similar duration of effect
compared with oxymorphone
 Administered IV, IM, SC to dogs and cats
 Used as a premedication alone or with a
tranquilizer
 Less expensive than oxymorphone
 Schedule II drug (United States) and narcotic
(Canada)

31. 31Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Methadone
 Synthetic opioid
 Characteristics similar to oxymorphone and
hydromorphone
 Least likely to cause vomiting in cats and
dogs
 Antagonist at the NMDA receptor

32. 32Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Fentanyl
 One of the most potent analgesics known
 Rapid onset (2 minutes) and short duration of
effect (20-30 minutes) when administered IV
 Administered by continuous IV drip,
transdermal patch, IM, SC, or epidural
injection
 Used in combination with midazolam or diazepam
drawn into separate syringes
 Schedule II drug (United States) and narcotic
(Canada)

33. 33Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Meperidine/Pethidine
 Pure opioid agonist with less potent analgesic
properties and shorter duration of action
 Administered by SC injection
 Wide margin of safety
 Used mostly as a preanesthetic in combination
with atropine or acepromazine
 When used with a tranquilizer, it provides effective
neuroleptanalgesia in puppies
 Used with injectable NSAIDs to provide analgesia
before NSAIDs take effect
 Schedule II drug (United States) and narcotic
(Canada)

34. 34Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Butorphanol
 Synthetic opioid with agonist and antagonist
properties
 Stimulates kappa receptors and blocks mu
receptors
 Not as effective an analgesic as a pure agonist
 Produces less sedation, dysphoria, and respiratory
depression
 Can be used to reverse the effects of morphine
and fentanyl

35. 35Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Butorphanol (Cont’d)
 Used as a preanesthetic, sedative, and
postoperative visceral analgesic
 Administered IV, IM, SC, or orally (as tablets
for long-term analgesia)
 Constant rate infusion IV can prevent redosing
 Schedule IV drug (United States) and
controlled drug (Canada)

36. 36Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Buprenorphine
 A partial mu agonist that produces some analgesia
for mild to moderate pain
 Used to provide postoperative analgesia to dogs and cats
 Can be used to reverse the effects of morphine and fentanyl
 Administered IV, IM, or epidural; orally to cats
 Delayed onset of action and longer duration of
analgesia
 Used with a sedative it can prolong sleep times
 Expensive Schedule V drug (United States) and
unavailable in Canada

37. 37Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioid Agents: Nalbuphine
 Kappa agonist and mu antagonist with
greater antagonist properties than
butorphanol
 Weak analgesic and sedative
 Used as a reversal agent for opioid agonists
 Fewer adverse effects
 Not a controlled drug in the United States

38. 38Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids as Postoperative Analgesics
 Administered IM or SC before animal regains
consciousness
 Injections repeated as necessary
 Alternative routes (IV, epidural, intraarticular,
transdermal patch) minimize adverse effects
 Disadvantages
 Short duration of action
 Potential adverse reactions: respiratory depression,
bradycardia, excitement, apprehension,
hypersalivation, mydriasis, excessive sedation,
panting, increased sensitivity to sound, urinary
retention, gastrointestinal effects

39. 39Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Intravenous Infusion
 Morphine, fentanyl, oxymorphone,
hydromorphone, methadone, butorphanol
 Provides continuous analgesia for constant,
unremitting pain

40. 40Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Intravenous Infusion
(Cont’d)
 Initial loading dose given to effect followed by same
dose given over 4 hours through constant flow
 Drug may be added to a bag of fluids if an automated
infusion pump is not available
 Monitor patient frequently for adequate pain control,
excessive sedation, or adverse effects
 Adjust rate of administration according to patient response
 Morphine (for example) can administered with
lidocaine or lidocaine/ketamine to control severe pain

41. 41Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Intraarticular Injection
 Especially useful after elbow or stifle surgery
 Morphine diluted in saline instilled into joint
via catheter
 Immediately after joint closure
 Can be combined with a local anesthetic
(e.g., bupivacaine)
 Provides 8-10 hours postoperative analgesia

42. 42Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Epidural Injection
 Instillation of opioid into epidural space at
lumbosacral junction
 To provide analgesia to hind limbs, abdomen,
caudal thorax, pelvis, tail
 Morphine is the most commonly used drug
 May be combined with an alpha2-agonist in large
animals
 Profound postoperative analgesia with long
duration of action

43. 43Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Epidural Injection (Cont’d)
 Instillation of an opioid into the epidural space
at the lumbosacral junction
 Administer after induction of anesthesia, but
before surgical procedure begins
 Onset of action: 20-60 minutes
 Duration of action 6-24 hours
 Must be supplemented with general anesthesia for
surgical procedures
 Reposition animals every 2-4 hours to prevent
pulmonary atelectasis or prolonged pressure on
superficial nerves

44. 44Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Transdermal Use
 Fentanyl transdermal patch
 Reservoir of fentanyl enclosed in plastic
 Attached to clipped skin and left in place for
several days
 Comes in various sizes
(25 mcg/hr; 50 mcg/hr; 75 mcg/hr; 100 mcg/hr)
 Large animals may require more than one patch

45. 45Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Transdermal Use (Cont’d)
 Provide convenient, long-term opioid
administration
 Similar to IM oxymorphone injection but longer
duration of action
 Delay of action from 4 to 12 hours (cats) or 12 to
24 hours (dogs) as drug is absorbed through the
skin
 Apply patch at least 6-12 hours prior to the start of
surgery
 Supplement with another opioid or NSAID if patch
isn’t applied until after surgery

46. 46Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Fentanyl Patch
 Use: Provide analgesia for postoperative pain
and pain associated with trauma, burns,
cancer, and painful abdominal conditions
 Amount of drug absorbed through skin varies
among animals
 Monitor for breakthrough pain and supplement as
necessary
 Monitor for fentanyl overdose
• Ataxia and sedation (dogs)
• Dysphoria and disorientation (cats)
 Remove patch if necessary

47. 47Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Opioids: Fentanyl Patch (Cont’d)
 Heat may increase the amount of fentanyl
absorbed
 Avoid using in animals with fevers
 Avoid contact of patch with external sources of
heat (e.g., hot water bottles)

48. 48Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Nonsteroidal Antiinflammatory Drugs
 NSAIDs or nonsteroidal antiinflammatory
analgesics (NSAAs)
Acetylsalicylic acid (aspirin) Carprofen
Acetaminophen Etodolac
Meloxicam Tolfenamic acid
Ketoprofen Deracoxib
Firocoxib

49. 49Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Nonsteroidal Antiinflammatory Drugs
(Cont’d)
 Mechanism of action
 Efficacy: somatic and visceral pain (varies by
drug)
 Onset of action: 30-60 minutes
 Duration of effect varies with species
 Toxicity varies with species
 Analgesic and antiinflammatory properties vary by
drug
 Inhibit prostaglandin synthesis by inactivating COX
isoenzymes
 Metabolized in the liver; eliminated by the
kidneys and the gastrointestinal tract

50. 50Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Adverse Effects of NSAIDs
 Prevent the production of beneficial
prostaglandins along with the production of
prostaglandins that mediate pain,
inflammation, and fever
 NSAIDs that inhibit the COX-2 enzyme but
not the COX-1 enzyme produce the least
adverse effects
 The perfect NSAID is not available yet

51. 51Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Adverse Effects of NSAIDs (Cont’d)
 Adverse effects vary with drug, species,
breed, and individual animals
 Stomach ulcers, vomiting, gastrointestinal
bleeding, lack of appetite
 Gastrointestinal ulceration leading to hemorrhage
 Renal toxicity
 Impaired platelet aggregation leading to prolonged
bleeding time
 Liver damage
 Antagonist to several drugs prescribed for cardiac
disease and hypertension

52. 52Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Other Analgesic Agents
 Opioids and NSAIDs are the most commonly
used analgesics
 Local anesthetics, alpha2-adrenergic agonists,
and ketamine are also used as analgesics in
special circumstances

53. 53Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Local Anesthetics as Analgesics
 Used to prevent or treat postoperative pain
 Sprayed or injected at the site of injury or surgical
site or infiltrated around a nerve supplying the
affected area
 Desensitize the entire region (epidural or IV
infusion)

54. 54Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Local Anesthetics as Analgesics
(Cont’d)
 Advantages
 Complete anesthesia of affected area
 Low toxicity
 Rapid onset of action
 Disadvantages
 Short duration of action
 CNS and cardiac toxicity with repeated use

55. 55Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Alpha2-Adrenoceptor Agonists
as Analgesics
 Limited use in small animals
 Short duration of analgesic effect
 Profound sedative effect
 Adverse effects: respiratory depression, vomiting,
bradycardia, heart block, hypotension
 When used in low doses may potentiate opioid
effects and increase quality of postoperative
analgesia
 Produce significant analgesia via the epidural
route alone or with other agents

56. 56Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Alpha2-Adrenoceptor Agonists
as Analgesics (Cont’d)
 Used in horses to provide sedation, muscle
relaxation, and analgesia
 Xylazine, detomidine, romifidine
 Horses remain standing but may become ataxic
 Analgesia okay for moderately to severely painful
diseases or procedures
 Adverse effects
• Cardiovascular effects, respiratory effects, GI effects
 Reversal with alpha2-adrenoceptor
antagonists will also reverse sedation and
analgesia

57. 57Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Ketamine as an Analgesic
 Used as an adjunct to more potent analgesics
(opioids, local anesthetics, alpha2-agonists)
 Doesn’t produce analgesia by itself
 MLK (morphine, lidocaine, ketamine) provides
intraoperative analgesia
 Blocks NMDA at the level of the spinal cord to
prevent windup
 Use a lower dose than the one used to induce
anesthesia

58. 58Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Ketamine as an Analgesic (Cont’d)
 Adverse effects: dose-related effects rarely
seen at analgesic levels
 Tachycardia
 Hypertension
 Seizures
 Postoperative delirium
 Increased intraocular and intracranial pressure
 Salivation

59. 59Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Corticosteroids as Analgesics
 Strong antiinflammatory properties
 Decrease prostaglandin activity such as NSAIDs
 Don’t use concurrently with NSAIDs
 Adverse effects
 Ulcerogenic
 Immunosuppression with long-term use
 Hyperadrenocorticism

60. 60Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Tramadol as an Analgesic
 Nonopiate drug with activity at the mu
receptor
 Also inhibits reuptake of norepinephrine and
serotonin
 Administered orally after patient has resumed
eating
 A postoperative alternative to opiates
 Can be administered at home
 Don’t use concurrently with other
norepinephrine or serotonin reuptake
inhibitors (e.g., amitriptyline)

61. 61Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Tranquilizers and Analgesia
 Tranquilizers are not considered analgesics
 May potentiate effects of opioids in anxious
patients
 Useful in calming the excitement sometimes seen
in cats and horses following opioid administration
 Cannot be substituted for opioids or other
analgesic agents

62. 62Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Multimodal Therapy
 Use of more than one type of analgesic to
relieve pain
 Pain is produced by several mechanisms
 Different drugs will target different mechanisms
along the pain pathway

63. 63Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Examples of Multimodal Therapy
 Acetaminophen and codeine
 Oral treatment for moderate to severe pain in dogs
 Fentanyl and meloxicam
 Administered at the same time to cats to provide analgesia
until the fentanyl patch takes effect
 Morphine and injectable NSAID (meloxicam or
carprofen)
 Administered at the end of surgery followed by oral NSAID
for 3 days
 MLK
 Administered in IV fluids during surgery, decreases amount
of inhalant anesthetic needed

64. 64Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Home Analgesia
 Fentanyl patches
 Used sequentially for up to several months for
chronic pain (dogs and cats)
 NSAIDs
 Long-term therapy of chronic painful conditions
 Oral morphine
 Sustained-release tablet administered BID to
effect
 Tylenol with codeine (dogs) and butorphanol
 Tablet for mild-to-moderate pain
 Tramadol

65. 65Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Nursing Care
 Relieving patient discomfort will help pain
control
 Keep patient and cage or stall clean and dry
 Comfortable bedding/quiet surroundings
 Opportunity to urinate and defecate
 Comfortable position
• May have to turn every 2-3 hours
 Reduce anxiety with toy or blanket from home
 Ophthalmic ointment in unconscious patients to
prevent corneal drying
 Comforting reassurance through touch and talking

66. 66Copyright © 2011, 2003, 2000, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.
Nonpharmacologic Therapies
 Used in conjunction with or as an adjunct to
pharmacological therapy
 Acupuncture
 Transcutaneous electric nerve stimulation
 Massage therapy
 Apply cold (acute injuries) or heat (chronic injuries)
 Physiotherapy
 Laser or magnetic therapy
 Homeopathic or herbal remedies