Analgesics Flashcards
where do you find nociceptors?
skin, tendons, jts, body organs, meninges
how does peripheral neuropathic pn generally present?
as burning, sharp, shooting or aching pain and mb associated w/tingling or numbness
different approaches to treating nociceptive pn vs chronic neuropathic pn
nociceptive pn generally tx w/anti-inflammatories or analgesic meds
neuropathic pn may be tx w/meds that act to influence neurotransmitters in addition to using anti-inflammatories and analgesics
what, ultimately, are analgesics? what can narcotics cause? what are opioids?
6 types of narcotic analgesics?
analgesics are pain killers
narcotics cause delirium and drowsiness
narcotic analgesics are st referred to as opioids b/c contain opium derivatives
examples: morphine, heroin, codeine, methadone, pethidine, fentanyl
what category is heroin?
category I - no accepted medical use
solubility of heroin?
more lipid soluble= more rapid crossing of the BBB, generally produces a much greater sense of euphoria than morphine
primary indication for opioids? MOA?
have a broad range of effects but primary use is to relieve intense pain and anxiety that follows pain
MOA: bind to specific opioid receptors in order to produce effects that mimic the actions of endogenous neurotransmitters referred to as opiopeptins
what are opiopeptins? 2 examples?
opioid receptor specific endogenous neurotransmitters
examples: include peptides such as the endorphins and enkephalins
MOA of opiate analgesics specifically?
opioid receptors are G protein couple receptors and therefore opioids work by inhibiting adenylate cyclase
they are also involved in postsynaptic hyperpolarization and reduce presynaptic Ca2+ influx which overall inhibits neuronal activity = less pain (sensation and perception)
5 areas of high density opioid receptors?
brainstem medial thalamus spinal cord hypothalamus limbic system also found on peripheral sensory nerves
analgesic properties of opiates are primarily mediated by what subclass of receptors?
mu receptors
enkephalins interact with what receptors where?
interact w/the delta receptors peripherally
which receptor type tends to be less selective and interacts w/drugs such as phencyclidine (hallucinogen)?
sigma receptors: therefore may be responsible for hallucinations and dysphoria often assoc w/opiate use
what is the effect of opioids and opioid agonists on nerve cells?
cause hyperpolarizaiton resulting in inhibition of further nerve firing
also opioid receptor stimulation causes presynaptic inhibition of the release of various pain mediators such as substance P
4 highly used opiate/narcotic analgesics?
morphine sulfate/MS contin
fentanyl/duragesic
codeine/T#3, T#4
tramadol/ultram
class of morphine/MS contin? indications? MOA?
class: opioid analgesic
indications: pain relief, acute MI, peripheral vasodilator
MOA: potent opioid agonist, high affinity for mu receptors; relieves pn both by raising pn threshold at brainstem, thalamic and spinal cord level as well as altering brain’s perception of pain
does morphine act on the peripheral or central nervous system?
central nervous system
high potential for addiction and tolerance (physical and psychological)
how to rx morphine/MS contin? how does tolerance work?
can give PO, PR, IM, IV; duration of action varies by route, significant 1st pass w/oral
high risk of developing tolerance
tolerance is generally dt increased breakdown of drug by up-regulation of -P450 system in the liver or by down-regulation of # of receptor sites in the brain
SEs of morphine?
respiratory depression by reducing sensitivity of respiratory center to CO2 (MC cause of death related to morphine), miosis, itching, N/V dt stimulation of chemoreceptor center in the brain, constipation dt reduced GI SM motility, paralytic ileus
class of fentanyl/duragesic? indications? MOA? how to rx? onset?
class: opioid analgesic
indications: pn relief, anesthesia
MOA: similar to morphine w/80x analgesic property of morphine, used for anesthesia and intractable pn
rx IV, transdermal patch, buccal lozenge, film, sublingual spray and lollipop form
onset of action w/in mins
single IM doses have DOA of 1-2 hrs, single IV doses last 30 mins-1 hr
SEs of fentanyl/duragesic? what category?
respiratory depression w/life threatening hypoventilation, pts using concomitant CYP450 inhibitors may result in fatal blood levels, N/V, constipation, paralytic ileus, highly addictive
category C drug
what is the only way to rx and receive transmucosal immediate release fentanyl products?
pt and doc have to be a part of the TIRF ACCESS program
effects of EtOH, grapefruit juice and St. John’s wort on fentanyl/duragesic?
EtOH may increase CNS depression
grapefruit juice increases fentanyl concentrations in the blood
st. John’s wort can decrease fentanyl levels
what is buprenorphine? what can it be used to tx?
semi-synthetic opioid that is used to tx opioid addiction in higher doses
can be used to control moderate acute pain in non-opioid tolerant individuals in lower doses and to control moderate chronic pain in dosages ranging from 20-70 millig/hr
class of codeine/T#3, T#4? indications? MOA? how to rx?
class: opioid analgesic
indications: pn relief, antitussive
MOA: opioid agonist, converted to morphine in the body but mg per mg, codeine is a much weaker analgesic then morphine
rx via PO, IV, IM, SQ- lower abuse potential than more potent narcotic analgesics
dosing form of codeine/tyelenol #3, #4? DOA? schedule?
PO, mc syrup form as an antitussive
DOA 4-6 hrs
DEA schedule II drug
SEs of codeine/T#3, T#4? do not give to what group b/c of what?
sedation, constipation, itching, increased potential for exaggerated response in certain individuals at risk dt genetic variability
do not give to those who have just received a tonsillectomy and/or adenoidectomy as there was an increased occurrence of death w/this pattern dt being ultra-rapid metabolizers of codeine dt CYP2D6 polymorphism
MOA of tramadol/ultram?indications for tramadol/ultram? what receptor does it affect, what neurotransmitter? SEs?
MOA: centrally-acting analgesic via the mu opioid receptor and affecting re-uptake at the noradrenergic and serotonergic systems
indications: to tx moderate to severe pn, suggested that it may be effective for alleviating sxs of depression, anxiety and phobias
SEs: respiratory distress, drowsiness, withdrawal-like sxs if weaned off too quickly or abrupt discont
5 acetaminophen-containing narcotic analgesics?
codeine/acetaminophen -T#3, T#4
hydrocodone/acetaminophen - vicodin, lortab
oxycodone/acetaminophen- percocet, roxicet
propoxyphene/acetaminophen- darvocet
tramadol/acetaminophen - ultraset