advanced pain Flashcards
What is pain?
Pain is a highly personal and subjective experience. The patients self-report of pain is the most reliable pain indicator.
Pain Perception
A fibers- dont transmit pain impulses, they transmit TOUCH and TEMPERATURE. Large fibers can block small fibers.
Gate Control Theory
Sensory and emotional experience.
Interneurons act as a gate by blocking ascending transmission pain impulses. These impulses can be modulated or adjusted. Gates can be closed by larger A fibers and by descending impulses down the spine.
Some factors affect this: like learned experience, cultural expectations, individual tolerance, placebo effect….. can activate the descending inhibitory nerves for upper CNS.
Opioid receptors in CNS, GI tract, and peripheral nerves.
Narcotic agonsists
Narcotic (opiod) agonists: Codeine Fentanyl hydocodone hyrdomorphone (dilauded) meperidine methadone morphine oxycodone tramadol
Actions:
They act on specific receptor sites, and produce analgesia, sedation, and a sense of well being.
Indications:
They relieve severe acute or chronic pain.
Pharmacokinetics:
IV used to achieve most therapeutic response.
Metabolized through liver and excreted through urine.
Adverse reactions:
Respiratory depression, CNS depression, and opioid induced constipation.
Fentanyl
IV, transdermal patch, or lollipop
dose starts at 25mcg, then increases
lasts 72 hours
opioid tolerance and addiction
narcotic antagonists
Maximum safe dosage to be invidisually assessed. Tolerance develops when taken for prolonged periods… then you need to increase dosage. You will go through withdrawal when opioid is discontinued.
Naloxone
Action:
Naloxone is a narcotic antagonist that binds to the opioid receptors, and reverses the effects of opioids. They DO NOT activate the opioid receptors.
Indication:
Reverses adverse effects of narcotics, like respiratory depression and sedation. Also used for overdoses.
Pharmacokinetics:
Metabolized in liver, excreted through urine. It CAN enter breast milk.
Neural blockade
remember neURAL= epiDURAL
epidural: a catheter is placed in the subarachnoid or epidural space at thoracic/lumbar level for administration of opioid or anesthetic agents.
monitor vital signs and look for headaches and pruritus (itching).
Non opioid analgesics
Analgesics (pain relief)/Antipyretic (fever reducer):
Acetaminophen (1st line of treatment)
Acetylsalicylic acid (aka aspirin and is an NSAID)
NSAIDs:
Ibuprofen: inhibits platelet aggregation (blood clots/thrombocytopenia)… so it can cause bleeding since the blood cant clot… and will also interact with other medications that may cause bleeding. Examples are anticoagulants and acetylsalicylic acid.
Centrally acting muscle relaxants
These medications have a systemic effect!
Examples are baclofen and cyclobenzapine
They are used to treat whiplash, herniated discs, muscle spasms, and fractures or dislocations.
Actions:
work in the CNS to interfere with the reflexes that are causing the muscle spasm
First, you must RICE Rest Ice Compress Elevate
Direct acting skeletal muscle relaxants
Enter the muscle directly, therefore the muscle relaxes without depressed respiratory system or consciousness. It treats muscle spasticity and spasms that directly affect peripheral muscle contraction.
Example:
Dantrolene
Actions:
Dantrolene directly affects peripheral muscle contraction and has become important in the management of spasticity associated with neuromuscular diseases. Dantrolene acts within skeletal muscle fibers, interfering with the release of calcium from the muscle tubules. This action prevents the fibers from contracting.
Used for CP, MS, and quadriplegia
Narcotic agonist-antagonists (not in med list, but might be good to know)
The narcotic agonists–antagonists stimulate certain opioid receptors but block other such receptors. These drugs, which have less abuse potential than the pure narcotic agonists, exert a similar analgesic effect as morphine. Like morphine, they may cause sedation, respiratory depression, and constipation.
Examples are buprenorphine, butorphanol, nalbuphine, and pentazocine.
