Analgesic drugs Flashcards
Allodynia
a pain responce to an non-painful stimulus
Hyperalgesia
increased pain from a stimulus that normally provokes pain
Hypoalgesia
diminished pain in response to a normally painful stimulus
neuralgia
pain in the distribution of a nerve or nerves
neuritis
inflammation of a nerve or nerves
noxious stimulus
a stimulus that is damaging or threatens damage to normal tissues
nociception
the neural process of encoding noxious stimuli
nociceptor
a high threshold sensory receptor of the peripheral somatosensory system that is capable of transducting and encoding noxious stimuli
nociceptive pain
pain that arises from actual or threatened damage to a non-neural tissue and is due to the activation of nociceptors
neuropathic pain
pain causes by a lesion or damage or disease of the neurons or somatosensory nervous system
WHO therapeutic recommendations for mild pain 1-3/10
nonopioid analgesic NSAID ; regular scheduled dosing
WHO therapeutic recommendations for moderate pain 4-6/10
add an opioid to the nonopioid for moderate pain with regular scheduled dosing (weak opioid)
WHO therapeutic recommendations for severe pain 7+/10
switch to a high potency opioid; regular schedules dosing
what analgesics work at the transduction/ local level to modulate pain
LAs, Capsaicin, Anticovulsants, NSAIDs, ASA, acetaminophen and nitrate
what analgesics work at the transmission/ peripheral nerve level to modulate pain
LAs, opioids, and a2 - agonists
what analgesics work at the modulation level in the spinal cord to modulate pain
TCAs, SSRIs and SNRIs
what analgesics work at the brain/perception level to modulate the pain
Opioids, TCAs, SSRIs, SNRIs, and a2- agonists
what are the 2 types of analgesics
1) opioid
2) non-opioid
what are the 2 types of non-opioid analgestics
1) Non-Steroidal Anti Inflammatory Drugs (Cox, Ibuprofen, Naproxen etc.)
2) anti-inflammatory agents (NSAIDs or glucocorticoids)
what are the 3 endogenous opioid peptides
1) endorphins
2) enkephalins
3) dynorphins
what are endorphins derived from
POMC
what is the primary agonist of endorphins
mu and also has delta action
what are enkephalins derives from
proenkephalin
what are the primary agonist of enkephalins
mu and delta
what are dynorphins derived from
kappa agonist and have mu and delta action
what is a opioid
any natural occurring, semi-synthetic or synthetic compound that bind specifically to the opioid receptors and share the properties of one or more of the naturally occurring endogenous opioids
what is an opiate
any naturally occurring opioid derived from opium
what are strong agonists
- morphine
- fentanyl
- hydromorpone
-meperidine - oxymorphone
- oxycodone
what do strong agonists have in common
they have a high affinity for certain receptors and are believed to interact primarily with mu opioid receptors in the CNS
Mild-to moderate agnoists
- codeine
- hydrocodone
mixed agonist-antagonist drugs
exhibit some of agonist and antagonist like activity at the same time because the drugs have the ability to act differently at specific classes or opioid receptors (for example they might bond to kappa but block mu)
what are some examples of mixed agonist-antagonist drugs
- buprenorphine
- nalbuphine
- pentazocine
what are the opioid antagonists
- naloxone and naltrexone
- they block all opioid receptors expecually mu; and can be used to help treat overdoses and addition
nalxone
the primary agent in the US to treat opioid overdoses when administered in an emergence situation it can dramatically reduce the respiratory depression that is usually the cause of death
naltrexone
is commonly used in conjunction with behavioral therapy to maintain an opioid free state for addicts
what are the common primary therapeutic effects of all 3 opioid receptors (mu,kappa, and delta)
spinal and supraspinal analgesia
what are the other effects of Mu
- sedation
- respiratory depression
- constipation
- inhibits neurotransmitter release (acetylcholine and dopamine)
- increases hormonal release
what are the other effects of kappa
- sedation
- constipation
- psychotic effects
what are the other effects of delta
- increases hormonal release (growth hormone)
- inhibits neurotransmitter release (dopamine)
what type of receptors are opioid receptors (m,k and delta)
Gi/10 protein-coupled receptors
what are the 2 establishes direct Gi/10 protein coupled actions on neurons
1) close Ca2+ gated channels on presynaptic nerve terminals and thereby reduce transmitter release (glutamine and substance P)
2) they open K+ channels on post synaptic neurons and hyperpolarize them thus inhibiting postsynaptic neurons
what are the 3 sites of action of opioid analgesics on the afferent pathway
1) on inflamed or damaged peripheral nerves
2) at the SC (Dorsal root)
3) the amygdala
what are the action of agonists
- analgesia
- respiratory depression
- spasm of smooth muscle of the GI and GU tracts, including the biliary tract
- miosis (pinpoint pupils)
what is the CNS effect of opioids
- analgesia
- euphoria
- sedation
- respiratory depression
- cough suppression
- miosis
- truncal rigidity
- nausea and vomitiing
- body temperature
- sleep disturbances