Pain Management Flashcards
What are some mechanistic approaches to pain management?
Remove cause
Decrease inflammation, irritation, and sensitivity of nerve endings (aspirin, nonsteroidal antiinflammatory drugs, and related agents).
Block conduction of impulses by pain fibers (local anesthetics such as lidocaine).
Modify the processing of pain information in the central nervous system (opioids such as morphine and related drugs; aspirin, acetaminophen, NSAIDs and related agents).
Acetaminophen
mechanism, where does it work, anti-inflame, GI and toxicity
Inhibits prostaglandin synthesis in nerve endings and CNS, but not in the periphery.
Alleviates pain by acting at nerve endings and in the CNS (exact mechanism of action is still not
clear)
No antiinflammatory activity
No tendency to cause GI irritation
Potential for hepatotoxicity at high doses
Ketorolac
alternative, side-effects, duration of use?
Injectable NSAID
Useful alternative to opioids for pain
Tendency to cause GI irritation
- inhibit prostaglandin production
- stomach prostaglandins stimulate mucus production and inhibit acid secretion
OK for short term (<1-2 days) use but not chronic
Local Anesthetics (lidocaine and related agents)
mechanism, fibers, pain relief, additional techniques
Block sodium channels in nerve endings and axons and stop generation and conduction of action potentials.
Small, unmylenated pain fibers are most sensitive but other neurons can be affected.
Powerful pain relief with spinal, regional and nerve block techniques.
Invasive procedures and may affect motor function and
sensory modalities.
Newer, low dose protocols provide more selective pain
relief without affecting other functions.
Techniques are being used increasingly for surgical pain
and chronic pain syndromes.
What are some adjuvant drugs for pain management
what do they act on, what are they useful in treating?
Corticosteroids, Disease Modifying Antirheumatic
Drugs (DMARDs) and Immunomodulators - act on
various components of the immune system; they are
useful in the treatment of inflammatory and
autoimmune disorders (e.g. rheumatoid arthritis and
lupus erythematosis).
Corticosteroids can have
powerful analgesic effects.
Additional adjuvant drugs for pain management
Muscle relaxants
Antidepressants
Anticonsulsants
Clonidine
Identify some muscle relaxants and antidepressants helpful in pain management, and what they do.
Muscle relaxants (e.g. diazepam, metaxalone, cyclobenzaprine, chlorzoxazone, tizanidine, etc).
- By relaxing skeletal muscle, they can break muscle spasms and are useful in the management of low back pain.
Antidepressants (*amitriptyline, imipramine, *duloxetine,
fluoxetine, etc..).
-They can alleviate symptoms of depression that commonly occur in patients with chronic pain and they can enhance the analgesic effects of opioids. In addition, some are beneficial in the treatment of neurogenic pain.
Identify some anticonvulsants helpful for pain and explain what clonidine is
*Carbamazepine, Valproic acid, *Gabapentin (Neurontin) and
*Pregabalin (Lyrica) - anticonvulsant drugs that are useful in the management of various types of neurogenic pain.
Clonidine – alpha 2 agonist that was originally used as an antihypertensive agent. It can enhance the analgesic effects of
opioids. A preparation of clonidine has been approved for use in spinal analgesia (Duraclon). Clonidine and other alpha 2 agonists may also be beneficial in pain syndromes involving activation of the
sympathetic nervous system (e.g. reflex sympathetic dystrophy).
Ketamine
use, military use, side-effects, cardiac, controversy
Older drug that is similar to Phencyclidine (PCP)
Has long been used as a “dissociative anesthetic” in
humans and animals.
Widely used by military in emergency trauma situations
in battle.
Lower doses are being used increasingly in pain management and psychiatry.
Potential for “dissociative” psychiatric side effects which can be very distressing to some patients.
Cardiac stimulation may be severe.
Controversy regarding use by law enforcement and first responders to calm agitated subjects.
Drug selection for mild pain
acetaminophen
aspirin
ibuprofen, ketoprofen, naproxen
Drug selection for moderate pain
Oral NSAIDs (especially for arthritis, musculoskeletal,
postsurgical and dental pain)
intermediate potency opioids (codeine, hydrocodone,
etc.) usually in combination with acetaminophen or aspirin.
Mixed agonist antagonist opioids such as tramadol would also be appropriate.
Drug selection for severe pain
Strong opioids (morphine, oxycodone, hydromorphone, fentanyl, methadone, etc.) either
alone or in combination with other agents.
Keep in mind that patients with severe pain may require higher than normal doses of opioids.
NSAIDS
Adjuvant drugs such as antidepressants, anticonvulsants, etc.
