Pain medications Flashcards
nociceptors
pain receptors
Signs of pain
Abnormal body position, movements, or limping
Increased heart rate
Increased breathing rate
Decreased appetite
Salivation
Vocalization
Tenderness
Restlessness
cells in damaged tissue release ____ _____ ____ and then
prostaglandins, histamine, and leukotrienes
they stimulate new blood vessels to grow and existing blood vessel walls to become leaky.
Bonus - The increased blood flow to the area brings in white blood cells to clear the area of foreign invaders and fibrin to plug the area
Drugs that reduce the inflammatory process include
NSAIDs (non-steroidal anti-inflammatory drugs), glucocorticoids,
DMSO (dimethyl sulfoxide, topical)
etc
pyrogen
A substance that raises body temperature.
pyrogens affect the hypothalamus and reset its thermostat to a higher setting.
NSAIDS primary meds to bring fever down
Pain is carried to the brain
through two different pathways
Type-C fibers are responsible for dull, nonlocalized pain,
Delta fibers are responsible for sharp, localized pain.
Controlling pain and inflammation is achieved through medications such as the following: (6)
NSAIDs
Opioids
Antihistamines
Muscle relaxers
Steroids
Nerve blocks
For the most effective pain control of severe pain, drugs from different categories are used together
Caution: steroids and NSAIDs should not be used together because of the increased risk of gastrointestinal side effects, ulceration, and bleeding.
NSAIDs.
*These drugs work by inhibiting the enzyme cyclooxygenase (cox).
NSAIDs offer analgesia and will lower temperatures. Not all NSAIDs block pain to the same degree. Some NSAIDs work very well and some work only for mild pain.
Inflammation analogy
inflammatory process like a waterfall.
The more water (top to the bottom) means more inflammation. If the waterfall is blocked near the top, inflammation is better controlled.
steroids (pain)
Are better anti-inflammatories than NSAIDs,
they appear earlier in the inflammatory cascade.
However, steroids, for some reason, don’t block pain or lower fevers.
NSAIDs side-effects
gastrointestinal bleeding and ulceration.
NSAIDs can also adversely affect the kidneys and cause clotting problems because they inhibit platelet aggregation
Any animal that stops eating, is vomiting, or has abdominal pain may have an ulcer and shouldn’t be given aspirin.
Aspirin
Is an NSAID that’s a/an
Analgesic (relieves pain)
Antipyrexic (relieves fever)
Anti-inflammatory (relieves redness, heat, swelling, pain)
Reducer of platelet aggregation
Liver
Everything below is BONUS
Buffered aspirin (that neutralizes both acids and alkalines) is preferred for dogs. It should be given with food to help protect the dog’s stomach from ulceration
Aspirin isn’t recommended for cats, because they don’t have the enzymes to metabolize this drug.
antipyrexic
Fever reducer
Acetaminophen
Limited use in veterinary medicine and should never be given to cats.
Propionic acid derivatives
Thought to work by inhibiting cyclooxygenase.
Carprofen is used in dogs to relieve arthritis or postoperative pain.
The drug has a long half-life of eight hours.
Processed in liver
α-2 adrenergic Agents
these drugs offer enough anesthesia for minor surgical procedures.
can alleviate stress for the animal and allow the procedures to be done more efficiently.
Bonus -
α-2 adrenergic agents include xylazine , dexmedetomidine.
principles that should be followed concerning corticosteroid therapy.
- Alternate-day dosing may help prevent iatrogenic hypoadrenocorticism.
- Administration should never be stopped abruptly but should be tapered off gradually.
- Very large doses may be used in emergency situations.
What function do mineralocorticoids serve in the body?
regulate electrolyte and water balance in the body
Iatrogenic
Caused by the vet
Side effects α-2 adrenergic Agents
Side effects of slow heart rate and low blood pressure are common, therefore they should not be used in animals with cardiovascular disease.
side effects of of short-term and long-term corticosteroid
Short-term effects of corticosteroid use include polyuria, polydipsia, polyphagia, and delayed healing.
Long-term effects include thinning of the skin, gastric ulcers, osteoporosis, and iatrogenic Cushing’s disease.
local anesthetic agents
Local anesthetics work by preventing the generation and conduction of nerve impulses in peripheral nerves
Used for
* Infiltration of local areas
* Epidural anesthesia
* Topical application in the eye, ear, and larynx, among others
* Nerve block
* Antiarrhythmic effects
4 steps of pain production
Transduction, transmission, modulation, and perception
Histamine
A major chemical mediator involved in allergic responses,
Two types of receptors for histamine exist, H1 and H2.
H1 receptors
Histamine receptor associated with the allergic response, nausea, or motion sickness.
H2 receptors
Histamine receptor associated with acid production in the stomach.
Glucocorticoids
exert anti-inflammatory effects, immunosuppressive (at higher doses) effects, and also influence the metabolism of carbohydrates, fats, and proteins.
Forms of cyclooxygenase and NSAIDS
Cox-1 and cox-2.
*Those NSAIDs that selectively block cox-2 are preferred because they’re associated with fewer gastrointestinal side effects.
