Module 5: Anti-Inflammatory and Pain-Reducing Drugs

Acute pain

Serves a purpose to warn against further damage

Chronic Pain

Pathologic/maladaptive- serves no biological purpose

Nociceptive

Normal processing of stimuli that damages normal tissue

Somatic

Well localized, aching or sharp (broken bone, cut etc)

Visceral

Aching, can be localized or generalized

Neuropathic

Pain from nervous system (abnormal processing of sensory input)

Chronic

Starts with acute pain → Prolonged pain→ Modification of the Nervous System

Nociceptive Pain Pathway

the neural process of detecting, transmitting, and interpreting noxious stimuli (tissue damage, extreme heat/cold) through four main phases: transduction, transmission, modulation, and perception

Transduction

Conversion of noxious stimuli into nerve impulses

• Local anesthetics, opioids, NSAIDs

Transmission

Traveling of nerve impulses from site of transduction to spinal cord

Modulation

Either increase (glutamate and substance P) or decrease (endorphins and serotonin) pain signal by neurons

Perception

The awareness and physical/emotional experience of the pain by the animal

List some severe pain scenarios

¡Osteosarcoma/Other Cancer Pains

¡Respiratory Distress

¡Urinary Blockages

¡Gastric Dilatation Volvulus

¡Spinal Pain

¡Trauma

¡Bone Fractures

¡Thromboembolism

¡Invasive Surgeries

Should pain be used to keep an animal more quiet?

No, use sedatives or anti-anxiety medications to keep them calm

How to identify pain?

Gentle pressure around the affected areas

If resp/ heart rate goes up can be sign of pain

Pain Scale

What is wind up pain?

Increase in pain perception or sensitivity to pain, often as a result of prolonged/ severe pain.

*Multimodal pain control*

The uses of a combination of drugs from different classes that target different sites along the nociceptive pain pathway.

Ex. Use of opioid and NSAID after orthopedic procedure.

• creates synergistic effect

Difference between Dysphoria and Pain

Dysphoria- thrashing and paddling, usually inconsolable, does not react abruptly when painful area is palpated

Pain- shaking, can be consoled to some degree

List the two common analgesics

Opioids and NSAIDs

Are opioids always controlled?

Yas

Do opioids cause some degree of sedation?

Yes, but not anesthesia

Some characteristics of opioids?

• controlled

• Cross placenta slowly

• Metabolized by liver

• Eliminated by kidneys

• Act on opiod receptors found in nervous system

Opioid adverse effects?

¡Respiratory depression

¡Panting (affect thermoregulators)

¡Salivation, vomiting, bradycardia,

• Constipation (effect GI movement and sensation)

Mu receptors ??

Dogs

Kappa receptors??

Horses/birds

What type of agonists can opioids be classified as?

• Full Agonists

• Partial Agonists

• Agonist-Antagonistcs

Name a drug that reverses mu and kappa agonists

Naloxone, an opioid antagonist.

**Affinity**

Measure of strength at which a drug binds to its receptor

**Potency**

Measure of amount of drug to produce desired effect (dosage needed)

What are analgesics

Drugs that relieve pain without loss of conciousness

Where do narcotics act on

Act on CNS → opiods/opiates

Where do non narcotics act on

Peripheral receptor sites or inflammatory pathway → NSAIDS

Opiate

Naturally derived from opium poppies

Opioid

Synthetic opiate

What is neuroleptanalgesia

Combine opioid and sedative

Characteristics of opioids 6

• antitussive

• Anti diarrheal

• Analgesia

• Controlled

• Cross placenta

• Metabolized by liver, eliminated by kidney

Adverse effects/cautions of opiods 6

• respiratory depression

• Panting

• Constipation

• Excitment

• Vomiting

• Brady cardia

What is the Mu receptor responsible for 4

• analgesia

• Euphoria

• Resp depression

• Hypothermia

What is the kappa receptor responsible for 3

• spinal analgesia

• Sedation

• Depression

4 opioid classifications

Full agonists

Partial agonists

Agonist-antagonists

Opioid antagonists

What is a full antagonist and provide 7 drug names

Bind to receptor & provide high level of analgesia

• morphine

• Hydromorphone

• Oxymorephone

• Hydrocodone

• Fentanyl

• Methadone

• Codiene

What is a partial agonist and provide one drug in this class

Affinity to some receptors, lower efficacy

• Buprenorphine

What is an agonist-antagonist and name one drug in this class

Act as agonist at one receptor but as an antagonist to another

• Butorphanol

What can Butorphanol be a reversal agent against

Full Mu agonists

What is an opioid antagonist and provide one example

Reversals

• naloxone

Efficacy

Drugs capability to produce an effect

Name some adverse effects of steroids

• Cushing like effects:

• PUPD

• Induce parturition

• Muscle wasting

• GI ulceration/bleeding

• Delayed wound healing

What is the main glucocorticoids in the body and what are its functions

Cortisol

• influences metabolism & anti inflammation

Are steroids analgesics

No

Main mineralcorticoid in body and what are its functions

Aldosterone

• retention of sodium and water

Do steroids cure inflammatory disease or just manage the clinical effects of disease?

Manage clinical effects of disease

Activity

Ability of that drug to cause action in or on a cell which the receptor is found

What is a major caution in tramadol

Dangerous in dogs→ serotonin syndrome!

Why is Buprenorphine not given orally?

They have first pass liver metabolism

What is inflammation a response from

Cellular damage

2 phases of inflammation

Early/vascular

Delayed/cellular

5 cardinal signs of inflammation

Redness, heat, swelling, pain, loss of function

2 major categories of antiinflammatory drugs

• steroidal anti inflammatories

• Nonsteroidal anti inflammatories

Where are steroids produced in the body

Adrenal cortex→ corticosteroids

Endogenous: produced naturally in body

Exogenous: drugs

2 types of corticosteroids

Glucocorticoids (cortisol, anti-inflammatory)

Mineralcorticoids (aldosterone)

Use of glucocorticoids (ends in SONE) 6

• antiinflammatory

• Antineoplasia

• Antiallergy

• Antipruritic

• Immunosuppressant

• Aural hematoma

What enzyme do glucocorticoids inhibit

Phospholipase

2 major cautions associated with glucocorticoids

• don’t give with NSAIDS

• Don’t stop suddenly

Name 6 steroids

• prednisone

• Prednisolone

• Dexmethazone

• Betamethasone

• Hydrocortisone

• Mometasone

What enzyme do Nonsteroidal anti inflammatories inhibit

Cyclooxygenase (COX) catalyze production of prostaglandins

What is COX-1 and COX-2

COX-1- (good prostaglandins→maintain renal blood flow, protect stomach lining, maintain platelet function)

COX-2- (bad prostaglandins→ promote inflammation)

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