pain control Flashcards
pain is a normal response to —-
-Encourages —
-Can become —
-Can become —
definition:
—-an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage
- injury
- rest
- pathological
- chronic
- pain
types of pain:
—- pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors
—- pain caused by a lesion or disease of the somatosensory nervous system (nerves that provide information about the body).
e.g. stroke, vasculitis, diabetes mellitus, genetic abnormality
—- pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain
e.g. fibromyalgia, non-specific low back pain
—- Both nociceptive and neuropathic eg cancer pain
- nociceptive pain
- neuropathic pain
- nociplastic pain
- mixed pain
aspects of pain:
1- —- :
-The neural process of encoding noxious stimuli
-Nociceptors are high-threshold sensory receptors of the peripheral somatosensory nervous system that are capable of transducing and encoding noxious stimuli.
2- — :
Pain in response to an innocuous stimulus ( basically it causes u pain even when its not supposed to)
Pain in dressing
Common in neuropathic pain
3- exaggerated response to noxious stimulus
nociception
allodynia
hyperalgesia
pain duration:
1- acute pain:
— response to injury and takes — which prevents further injury
2- subacute pain:
- is due to —
- triggers —
3- chronic:
- — pain— injury
- non involved in repair
- pathological
immediate
sec
acute inflammation takes hours
repair
prolonged
post
notiception has 3 domains which are:
1- biological/physical : due to genetics sex age sleep magnitude of disease or injury , decondintioning loss of grey matter , etc ( leads to pain)
2- psychological : depression anxiety coping skills personality , poor concentration , etc( leads to suffering )
3- socioculture: job satisfaction social support system language and cultural barrier , isolation
description of pain:
- biring stabbing electric shock like is —>
- tenderness ashiness and stiffness —>
- descprtiion of nerve pain
description of muscle pain
stages of pain:
1- activation of — as:
2- transmission of pain to — which is inhibited by — and —
3- transmission of pain to —
- pain receptors ( nociceptors ) as bradykinin histamines and sensisted by prostaglandins
- spinal cord
- inhibited by enkephalin and endorphin
- brain
pain fibers:
1- alpha omega ( check slide for name)
- — — fibers
- speed conduction of —
- triggers – withdrawal reflex
- produces ——- pain
- allows – of pain
2- c fibers
- – fibers
- speed of conduction is
- produce —– pain aka — pain
- thinly militated
- 5-35 m/s
- immediate
- sharp localised immediate pain
- localisation
- slower unmylinated
- 0.5-2 m/s
- dull diffuse pain
-2ndary pai
treatment of pain:
Analgesics are used to mask pain
They do not treat the underlying problem
They can lead to further injuries
Can be important to help in recovery
Target specific pain pathway involved
( check slide 15,16)
opioid analgesics:
1- —Compounds related to substances found in the opium poppy, e.g. —
2- —- Natural or synthetic compounds that cause opiate-like effects
opiate
morphine
opioid
—- is an enzyme that breaks down enkephalins
- thiorphan :
1- active metabolite of —
2- used as —
3- inhibits —
- Research on developing enkephalinase inhibitors for —-
- ennkephalinase
- racecadotril
anti-dirraheal - enkephalinase
- pain control
opioid receptors :
- 5 types of opioid receptors:
m (MOP)
k (KOP)
d (DOP)
nociceptin/orphanin FQ (N/OFQ) (NOP)
Opioid growth factor receptor
- they are —
- promotes opening of —
- reduces —-
- inhibits opening of —- channels
- reduces —–
- g protein (Gai-linked)
-k+ channels
-neural excitability - voltage gated ca2+ channels
- neurotransmitters
morphine:
- m, k and d receptor –
- Marked elevation in pain threshold without loss of — (m and k receptors)
- euphoria for – receptors :): pleasant, ‘floating’ sensation with freedom from anxiety [dysphoria in some subjects (k receptors)]
- given —
- variable —
- modest t1/2 = —
- sustained release oral preparation to— duration of action
- patient controled by —
- agonist
- consiocusiness
- u receptors
- orally s.c i.m i.v
- 1st pass metabolism
- 3-4 hours
- increase
- i.v analgesia
morphine side effects;
Sedation, mental clouding/drowsiness
Respiratory depression: inhibits brain stem regulatory centre
Nausea, vomiting
Constipation: increased GIT muscle tone, decreased propulsive movements, reduced sensory stimuli for defecation reflex
Miosis: important in diagnosis of overdose
Tolerance and dependence
- other opioid angonsit :
1- pethidine ( or meperidine) : - efficacy is — morphine
- — > – agnosts
- — acting often used in —
- less liable to cause —
2- codeine : - – efficacy of u > k agonist
- 10% converted to —
- alleviation of — pain
- 3- fentanyl:
- 100+x —- potent than morphine
- used for – pain
4- oxydocodone
5- tramadol : - inhibits — and — uptake
- usually prescribed w —
less or equal
u > k agonist
short acting used in labour
constipation
low
morphine
mild moderate pain
antitussive ( cough suppressant )
more
cancer pain
inhibits serotonin
noradrenaline reuptake
paracetamol
opioid antagonists;
1- naloxone:
- u > k receptor antagonist
- almost —
- — of opioid actions especially 000
- – half life of — relative to — hence the – administration
- available as —–
2- naltrexone:
- – half life
- available as —-
- approved for treatment of —- and —
- inert
- reversal
- overdose
- short half life of 1-2 hours
- relative to morphine
- repeated
- IV IM and intranasal formulation
- long
oral and long lasting injectable formulation - treatment of opioid use disorder OUD and alcohol use disorder AUD
abuse deterrence:
1- —- , abuse deterrent oxycodone using — technology similar release to immediate release —
- the sentry bond resits manipulation such as — and —–
2- —- which is ( — + — )
- prevents —-
- prevents —
- RoxyBond
- sentry bond
- oxycodone
- crushing and chemical extraction
- targin ( oxycodone + naloxone)
- constipation ( naloxone is poorly absorbed )
- prevents injecting the drugs
( the butter: RoxyBond is a newly approved opioid pain medication (approved in 2024) that features abuse-deterrent properties through its use of SentryBond technology. It is a formulation of oxycodone, a powerful opioid commonly used for pain relief.)
PGs, 5HT and bradykinin sensitise pain fibres are all —-
rather than cause pain they — pain fibbers making them more likely to response to other —- signals
- inflammatory mediators
- sensitise
- pain signals
—- are used to treat inflammation
- act to inhibits —- and —- productions
they are — and —- and —–
such as:
- NSAIDS
- cyclooxyrgenase and prostaglandin production
- anti inflammatory , analgesic and anti pyretic
as:
aspirin (irreversible)
ibuprofen
indomethacin
meclofenamate
diclofenac
anti inflammatory drugs:
— is a major cause of pain due to a specific —- mediator sensitising — fibers
- primarily — and —
- inflammation
- inflammatory mediators sensitising pain fibres
- prostagldins and calcitonin gene related peptides
COXIBS :
- COX II inhibitors are: — and —
- developed to protect against —
( Have similar efficacies to that of the non-selective inhibitors, but the GIT side effects are decreased by ~50%.)
- celecoxib and rofecoxib
- gastric ulceration
paracetamol is technically not — as its only used for — and — and not —
- MOA is unclear w multiple theories as:
- NSAIDS
- pain n fever and not inflammation
- theories are:
1- COX II selective inhibition
2- metabolites of paracetamols may inhibits nocipetors
read: CDC DATA
Nearly 15,000 people die every year of overdoses involving prescription painkillers.
In 2010, 1 in 20 people in the US (age 12 or older) reported using prescription painkillers for nonmedical reasons in the past year.
Enough prescription painkillers were prescribed in 2010 to medicate every American adult around-the-clock for a month.
Nearly half a million emergency department visits in 2009 were due to people misusing or abusing prescription painkillers.
Nonmedical use of prescription painkillers costs health insurers up to $72.5 billion annually in direct health care costs.
read:
-Many patients discontinue long term opioid therapy (especiallyoral opioids) due to adverse events or insufficient pain relief; however, weak evidence suggests that patients who are able to continue opioids long-term experience clinically significant pain relief. Whether quality of life or functioning improves is inconclusive. Many minor adverse events (like nausea and headache) occurred, but serious adverse events, including iatrogenicopioidaddiction, were rare.
-90% of all addictions begin in adolescence
-Less than 13% of patients treated for overdose were also being treated with chronic pain
-75% of people using opiates were not prescribed them by their doctor
Main risk factors for opiate addiction are:
-Poverty
-Mental illness
-Childhood trauma
-US ranks 34 out 35 top OECD countries for child poverty (Romania was 35). Probably the main driver of opiate epidemic in US
read:
Purdue pharma
Founded in 1892 in NY
Taken over by Sackler brothers (doctors)
Focus on pain management
Developed Contin sustained release formulation
MS Contin delivers morphine (1984)
OxyContin use this to deliver oxycodone (1996) - blockbuster
Promised a 2x day dosing
Not really - Patients required more than prescribed
78% heroin addicts started with OxyContin
Sued for bad business practices
$8 billion
Criminal prosecutions of senior management
Company converted into a public interest company
