243 Pain Flashcards
Describe chronic pain
Pain lasting over 3-6 months
Pain that occurs after tissue healing has taken place
Pain persisting after the course of acute disease
E.gs arthritis, cancer, fibromyalgia
Describe acute pain
Pain that lasts less than 3-6 months
May be postoperative pain or result from acute injury
What are the three main classes of pain?
Nociceptive
Neuropathic
Inflammatory
What is the Nociceptive classification of pain?
Normal response to noxius insult (painful stimuli) or injury of tissues, skin, muscle joints, tendons
Nociceptors react in response to something
Somatic (cells) usually localised eg. Hitting finger
Visceral: organs and smooth muscle, often referred eg. Heart pain causing pain in arm
What is post herpetic neuralgia?
When pain persists in someone that’s already HAD shingles (herpes zoster)
Tingly and uncomfortable pain.
Part of neuropathic pain classification.
What is inflammatory pain?
Results from activation of the Nociceptive pain pathway by a variety of mediators released in tissue inflammation
Pro-inflammatory cytokines eg IL1 alpha, IL1 beta, IL6, TNF a
Examples are rheumatoid arthritis, appendicitis, inflammatory bowel disease, herpes zoster (shingles- virus In nerve endings )
What are the 5 types of pain/ condition in the WHO classification of MuscoSkeletal disorders?
Inflammatory rheumatoid diseases eg RA Osteoporosis Osteoarthritis Soft tissue periarticular disorders Back pain
What are the types of pain that are hard to classify?
Cancer pain
Fibromyalgia
Migraine & other primary headaches
What causes Fibromyalgia?
The exact cause is unknown
What happens in people with fibromyalgia?
Disturbed pain messages
Low levels of hormones- dopamine, noradrenaline, serotonin
Sleep problems
Pain in upper back and around collar bones mostly
What areas does the pain effect with fibromyalgia?
Pain in muscles and fibrous tissues, such as from tendons and Ligaments
NB: it does NOT affect the joints (not arthritis)
What are the pharmacological options for treatment of fibromyalgia?
Analgesics
Antidepressants
Drugs currently being looked at: Pramipexole, Pregabalin
Any non-pharmacological options for treating Fibromyalgia?
Balneotherapy (Hot Pool)
Cognitive behavioural therapy (CBT)
Massages
First line treatment for Breakthrough pain?
ORAMORPH
An immediate release morphine
Consider if:
Intolerance to morphone
Unable to swallow
Rapid onset and short duration of BTP
What is the usual dose for breakthrough pain?
Between 1/6th -1/10th of the starting dose
Depends what is best for patient
Also used in Breakthrough pain but NOT first line?
Fentanyl products
Eg Actiq, abstral, Effentora
Consider if:
Intolerance to morphone
Unable to swallow
Rapid onset and short duration of BTP
Five types of Pain rating scales/ questionnaires you can think of?
Verbal rating scale Numerical rating scale Visual analogue score Visual recognition (Faces ) McGill pain Questionaire
What route of administration of analgesics should be used wherever possible?
ORAL administration
What’s the standardized dosage of pain medication such as stron opioids?
There isn’t one!!
Dosing of pain medication should be adapted to the individual
Every patient will respond differently
The correct dose is one that allows adequate relief of pain for that patient
Analgesics should be prescribed with a constant concern for detail. What does this mean?
The regularity of analgesic administration is crucial for the adequate treatment of pain.
Once distribution of medication over a day is established, it is good to provide a written personal program to the patient.
Patient family and medical staff will all have info on when to administer medicines
What is the WHO analgesic ladder ? (From 1-3)
1) paracetamol +/- NSAID
2) Step 1 + weak opioid
3) step 1+ strong opioid
What’s the WFSA analgesic ladder for ACUTE pain?
1) strong opioid by injection + local anaesthetic
2) opioids by mouth + paracetamol +/- NSAID
3) Paracetamol +/- NSAID
Step 2 of the WHO ladder is paracetamol + weak opioid. What weak opioid could be used?
Regular co-codamol
Dihydrocodeine
Step 3 of the WHO ladder involves Paracetamol + strong opioid. What strong opioid could be used?
Regular morphine
The newer version of the WHO pain ladder now includes some new additions.
What new additions are there to step 3?
(Strong opioids)
Methadone
Transdermal patch
The newer version of the WHO pain ladder now includes some new additions.
What does STEP 4 involve? (ADVANCED interventions)
Nerve block Epidurals PCA pump Neurolytic Block therapy Spinal stimulators
What is an NNT?
The higher the NNT number, the LESS effective the drug is at pain relief.
NNT= 1, everyone gets pain relief, good drug
NNT= 16, only 1 in 16 patients get pain relief from this drug
What analgesics have LOW NNTs? (Therefore v effective)?
Diclofenac 100mg- but CV risks now! (NNT1.9)
Paracetamol 1g + Codeine 60 mg in combo (NNT 2.2)
Naproxen 440mg (NNT 2.3)
Oxycodone IR 15mg (NNT 2.3)
Would you consider codeine as a monotherapy?
No not really
NNT of codeine 60mg monotherapy= 16.7!
Paracetamol + codeine = 2.2 (much better!)
Paracetamol 1g monotherapy = 3.8
Will NNT usually increase or decrease with INCREASING the dose of analgesic? (Eg tramadol?)
Decrease
This is expected; higher dose = more pain relief = lower NNT= more patients experience pain relief from this drug
What are some common unwanted side effects of the opioids?
Constipation
Nausea and vomiting
Respiratory depression
Is lower back pain acute or chronic pain?
Acute
What’s an example of intermittent pain? I.e can’t really specify if acute or chronic?
Migraine
TENs can be used to help chronic pain. What is this?
Electrical nervous stimulation machine
A machine used to stimulate nerves, place against the area with pain
Helps relieve pain without use of medication
People with chronic pain often get a “vicious cycle” of problems. What does this involve?
Pain leads to anxiety and depression, which can make pain worse (lowers pain threshold) as well as affecting sleep. Lack of sleep increases pain
Muscle tension is increased by pain and can also contribute to more pain itself as well as anxiety and sleep problems!!!
What agent is licensed for post-herpatic neuralgia?
Topical lidocaine (a local anesthetic)
This is questioned as an adjuvant, because it is directly used for pain
What medication is licensed for pain in painful diabetic neuropathy?
Duloxetine
Oral amitryptyline if Duloxetine contraindicated
What medication is licensed for Central and peripheral Neuropathic pain?
Pregabalin
What is FIRST line for treatment of neuropathic pain?
Oral AMITRIPTYLINE or Pregabalin
What are the doses for first line amitryptyline and Pregabalin in neuropathic pain?
Amitryptyline: start at 10mg per day
With a gradual upward titration to an effective dose or persons maximum tolerated dose. No higher than 75mg a day (gran was on 50mg!)
Pregabalin: start at 150mg a day (divided into 2 doses, a lower starting dose may be appropriate for some people), with upward titration to an effective dose or persons maximum tolerated dose of no higher than 600mg per day (divided into 2 doses)
What is the dose of first line Duloxetine in painful diabetic neuropathy?
Start at 60mg a day
With upward titration to an effective dose or the persons maximum tolerated dose of no higher than 120mg per day
What are adjuvant therapies?
Treatment given in addition to the main primary treatment (analgesic)
They’re not typically used for pain but may be helpful for its management
Antidepressants are an example of an adjuvant. What kind of pain do they help? Example drugs?
Neuropathic pain
Burning pain
Amitryptyline, imipramine
Muscle relaxants are an adjuvant. What drug examples are there?
These help Muscle spasms
Baclofen, diazepam, dantrolene
What adjuvant therapy can be used for Colic pain and smooth muscle spasms?
Antispasmodics
Eg Hyoscine
Hydrobromide
Loperamide
Bisphosphonates are as adjuvant in ______ pain.
Bone pain
Eg Clodronate
What is a McKinley t34??
A SYRINGE DRIVER!!
You can use it to automatically set the pump mechanism to an infusion rate over a given time
What’s a syringe driver?
A small battery operated device, it’s capable of pumping a volume of a solution over a period of time to provide a continuous subcutaneous infusion (CSCI)
What problems can occur with syringe drivers?
Mixing drugs
Stability of drugs in solution/ over time
Where’s the preferred site of Administration for syringe drivers?
Upper arm- first choice
Then chest wall, or abdomen
Then upper back
Then thigh
Goes in Via a subcutaneous infusion!!
There’s a section in the BNF on syringe drivers! (Just look in index)
It’s common for 1-3 drugs to be used together as a single solution in a syringe driver.
In specialist centres up to 5 drugs can be mixed together.
Most drugs used in syringe drivers are being used ‘off-label’
(The manufacturer wouldn’t usually recommend SC route or mixing in a syringe driver)
What’s the most common drug used in PCA?
Morphine 1mg/1ml in sodium chloride 0.9%
If a syringe driver does not control symptoms of pain, the use of an intrathecal (spinal) or epidural route may be considered.
What is this?
Injection into area around spinal chord (epidural and intrathecal inject into different areas)
Numbs lower body.
A type of neuraxial blockade
Who does the catheter for an epidural have to be inserted by?
By an anesthesist in theatre
An epidural and intrathecal (spinal) are generally made up of what drugs?
An Opioid in combo with an anaesthetic such as bupivacaine or occasionally Ketamine or clonidine.
The drug mixtures that go into an epidural and spinal must be ____ free and made under aseptic conditions
Preservative free
What’s the difference between a spinal and an epidural?
Epidural involves a catheter, spinal usually just one shot injection
Space injected into is larger in an epidural
Injected dose therefore larger in epidural
Onset of analgesia slower in epidural
Injected into different regions
Can Contain different opioids (epidural usually fentanyl)
What is neuropathic pain?
To do with somatosensory nervous system
Lesion/disease on nerves
Hyperalgesia, tingling (paraethesias), numbness
Examples: phantom limb, spinal chord injury, diabetic neuropathy, post-herpatic neuralgia
Neuraxial blockade with epidural or spinal anaesthesia reduces the incidence of _________ and ____ month mortality in ____ fracture patients
incidence of Deep Vein Thrombosis and One month mortality in hip fracture patients
Mortality has been seen to reduce by ______ of patients allocated neuraxial blockade
One third
In a study what 7 things was neuraxial blockade seen to reduce?
Risk of DVT Pulmonary embolism Transfusion requirements Pneumonia Respiratory depression Myocardial infarction Renal failure
What has it been announced that Botox could do?
Help soothe pain of cancer, arthritis, and migraines without the side effects
Where is the Botulinum (Botox) injection usually given to relieve pain?
Into a trigger point, an area in muscle where pain begins
It blocks messages that tell muscles to contract, so muscles stay relaxed an pain free
When a person having had a Botox injection is ready for their muscles to contract again as it’s about to wear off, what can they do to ease them into it and stop it being a painful wear off?
Doing a Gentle course of daily exercise will sometimes help the muscle to contract normally which prevents pain from returning, prevents the recurrence of pain!
Why are more people “dying in Agony” now that the Liverpool care pathway has been scrapped?
Because this pathway meant people at the end of their life we’re let to due by stopping giving them foods and liquids. Like a natural form of euthanasia.
Now people are left to live right up to then end of their life, which means they can die in agony.
What is hyperanalgesia and Allodynia?
Hyperanalgesia: response to stimulus that is slightly painful but person thinks it’s extremely painful
Allodynia: pain due to a stimulus that isn’t usually painful eg. Tickling!
Could a PPI be seen as an adjuvant therapy in pain?
Yes
Patient may be on it as they’re on an NSAID causing gastric irritation
Taking the PPI is seen as for a condition spurring from pain: so is adjuvant
Are muscle relaxants good for acute or chronic pain?
Acute pain
Not so good for chronic
Which are equivalent to the highest dose of morphine daily, transtec patched or Butrans?
Transtec patches
Release a higher dose of buprenorphine
Equivalent to much higher doses of morphine
How long are transtec patched put on for? What about Butrans?
Transtec for 4 days
Butrans for 7 days
How long are fentanyl patches put on for?
72 hours (3 days)
What are PCA pumps commonly used for?
Post-operative pain management
And end stage cancer patients
Tell me about Alfentanil,
What is it used for?
What’s about it’s potency?
Equivalence to 30mg oral morphine?
It’s about 30 X more potent that morphine (but Less potent than fentanyl)
It’s used for painful manouvres eg when a patient is moving beds.
Oral morphine 30mg is equivalent to SC Alfentanil 1mg
Alfentanil can come in a high conc preparation of 5mg/ml
Can get it in a sublingual / buccal spray that is 5mg/5ml
It’s a THRID LINE injectable opioid for moderate to sever pain in patient unable to tolerate morphine, diamorphine or oxycodone due to their side effects
If I’m working out morphine equivalence, and my patch works out as a dose just under then desired dose of morphine, should I just give two patches (then it’ll be over the required dose)?
No!
Always go under the required dose if you can’t make it exactly as this reduces chance of toxicity and overdose!!
Can always add more in later if this dose isn’t sufficient
What happens with opioids in someone with renal impairment?
THe effects are increased if renal impairment is under GFR 30ml/min, especially morphine and diamorphine as these will accumulate
When someone is “unable to tolerate opioids such as morphine, diamorphine, oxycodone due to persistent side effects” what are these side effects?
Sedation
Confusion
Hallucinations
