How to manage different types of pain

1. Management of Acute
and Chronic Pain
Dr Akinsowon Olusegun

2. • Pain is an unpleasant sensory and emotional
experience associated with actual or potential
tissue damage, or described in terms of such
damage
• Pain is a subjective experience. The experience
varies from person to person and from time to
time
–Pain is whatever the experiencing person says
it is, existing wherever he says it does

3. Total pain: how patients experience pain
3
TOTAL PAIN
PHYSICAL
PSYCHOLOGICAL EMOTIONAL
SPIRITUAL
• Patients experience pain on several levels and effective treatment
requires a holistic assessment
• This training program focuses on physical pain

4. • Analgesics are medicines that relieve pain
• Opioids are medicines that are derived from opium poppy
plants or synthetic formulations that act in the same way
–Weak opioids
• Codeine
• Tramadol
• Dihydrocodeine
–Strong opioids
• Morphine
• Fentanyl
• Oxycodone
• Hydrocodone
• Buprenorphine
• Methadone

5. IASP: Treatment of pain in low-resource settings (2010)Opioid analgesics for pain reliefOpioids are the foundation of pain management for moderate or severe pain
• No organ toxicity, even at high doses and
after prolonged use
• Side effects diminish over time
• Potential harmful side effects are
avoidable when opioids are used correctly

6. In low-resource countries, pain is the most common
indication for visiting a health care practitioner
Pain treatment:
• Improves compliance to curative treatment
• Extends survival for some patients
• Improves quality of life
• Improves patient – physician relationship
• Reduces unnecessary prolonged admission

7. Characterisation of Pain
• pain can be characterised
–Duration
–Mechanism
–Origin
–Situation

8. Pain can be described by its:
• Duration – acute or chronic
• Mechanism – nociceptive or neuropathic
• Origin – somatic or visceral
• Situation – incidental pain, breakthrough pain,
procedural pain

9. Duration; Acute vs Chronic
Acute pain
• Presentation: characterized by help-seeking behavior such as
crying and moving about in a very obvious manner
• Cause: definite injury or illness
• Signs/symptoms:
– Definite onset with limited and predictable duration
– Clinical signs of sympathetic over-activity: tachycardia,
pallor, hypertension, sweating, grimacing, crying, anxious,
pupillary dilation
• Example: trauma, surgery, or inflammation

10. Chronic pain
• Presentation: Patients may not show signs of distress
seen in acute pain
• Cause: chronic pathological process
–Under-treatment of acute pain can lead to changes
in the central nervous system that result in chronic
pain
• Signs/symptoms:
–Gradual or vague onset
–Continues and may become progressively more
severe
–Patient may appear depressed and withdrawn
–Usually no signs of sympathetic over-activity

11. Mechanism; Nociceptive
Pain
Nociceptive pain: caused when nerve receptors
called nociceptors are irritated. Nociceptors exist
both internally (visceral) and externally (somatic)
• Indicates that nerve pathways are intact

12. Somatic pain: stimulation of nociceptors in the skin,
soft tissues, muscle, or bone
• Pain usually is in a particular location
• Aching, throbbing, or persistent pain
• Causes: bone or soft tissue infiltration

13. Visceral pain: stimulation of nociceptors in internal
organs and hollow viscera organs
• Pain is often not in a single location
• Described as pressure, cramping, or squeezing
pain
• Causes: blockage, swelling, stretching, or
inflammation of the organs from any cause

14. Neuropathic pain: caused by damage to nerve pathways
• Described as burning, prickling, stinging, pins and needles,
insects crawling under skin, numbness, hypersensitivity,
shooting, or electric shock
• Causes: infiltration by cancer, HIV infection, or herpes
zoster, drug-related peripheral neuropathy, central
nervous system injury, or surgery

15. • Incident pain – occurs only in certain
circumstances (e.g. after a particular movement)
• Breakthrough pain – a sudden, temporary flare of
severe pain that occurs on a background of
otherwise controlled pain
• Procedural pain – related to procedures or
interventions

16. WHO Analgesic Ladder
• The WHO analgesic ladder was introduced in 1986
–3-step ladder for adults
–Updated in 2012 to include 2-step ladder for children
• Framework for pharmacological management of pain
• 80-90% of patients are effectively treated using the
WHO 3-step approach

17. 17
Mild pain
Moderate pain
Severe pain
Step 1
Non-opioid
Step 2
Weak opioid
Step 3
Strong opioid
+/- adjuvant
+/- non-opioid
+/- adjuvant
+/- non-opioid
+/- adjuvant
Consider prophylactic laxatives to avoid constipation
Step up if pain
persists
or increases
Step up if pain
persists
or increases
Non-opioids ibuprofen or other NSAID, paracetamol (acetaminophen), or aspirin
Weak opioids codeine, tramadol, or low-dose morphine
Strong opioids morphine, fentanyl, oxycodone, hydromorphone, buprenorphine
Adjuvants antidepressant, anticonvulsant, antispasmodic, muscle relaxant, bisphosphonate, or corticosteroid
Combining an opioid and non-opioid is effective, but do not combine drugs of the same class.
Time doses based on drug half-life (“dose by the clock”); do not wait for pain to recur
Adapted by Treat the Pain from World Health Organization http://www.who.int/cancer/palliative/painladder/en/ (accessed 7 November 2013)
WHO Analgesic Ladder: adults
4

18. • Mild pain - start with a non-opioid, for example with
regular paracetamol or non-steroidal anti-
inflammatory drug (NSAID), then move up steps if
pain remains uncontrolled
• Moderate - start with a weak opioid, for example,
codeine or low-dose morphine
• Severe - start with a strong opioid, for example,
morphine, to control pain early
• Adjuvants can be used at any step

19. Paracetamol
• Adult dose: 500mg-1g by mouth every 6 hours;
maximum daily dose 4g
• Note: Hepatoxicity can occur if more than the
maximum dose is given per day
• Paracetamol can be combined with an NSAID
Step 1 – mild pain: non-opioids

20. Ibuprofen (NSAID)
• Adult dose: 400mg by mouth every 6-8 hours;
maximum daily dose 1.2g
• Give with food and avoid in asthmatic patients
• The maximum dosing limit should be lowered
in patients with liver impairment

21. Diclofenac (NSAID)
•Adult dose: 50mg by mouth every 8
hours; maximum daily dose 150mg
•Give with food and avoid in asthmatic
patients

22. NSAIDs can cause serious side effects, particularly
after using for more than 7-10 days
• Gastro-intestinal (GI) bleeding or renal toxicity
–If GI symptoms occur, stop and give H2 receptor
antagonist. e.g. Ranitidine
• Not for use in patients with renal failure
Cautions with NSAIDs

23. Tramadol
• Adult dose: 50-100mg by mouth every 4-6 hours
• Start with a regular dose and increase if no response (dose
limit: 400mg/day)
• Use with caution in epileptic cases, especially if patient is
taking other drugs that lower the seizure threshold
• May cause serotonin syndrome in patients on other
serotonergic medications
Step 2 – moderate pain: weak opioids

24. Codeine
• Adult dose: 30-60mg by mouth every 4 hours; maximum daily dose
240mg
• If pain relief is not achieved with 240mg/day, move to strong
opioid
• Can be combined with Step 1 analgesic
• Give laxative to avoid constipation unless patient has diarrhoea
• Genetic variability can lead to variable rates of metabolism which
may make codeine ineffective or lead to excessive side effects

25. Low-dose morphine
• Some palliative care experts recommend
using low-dose morphine in step 2 because it
is associated with fewer side effects
compared to other weak opioids

26. Morphine
• “Gold standard” against which other opioid
analgesics are measured
• When used correctly, patients don’t become
dependent or addicted, tolerance is uncommon,
and respiratory depression doesn’t usually occur
Step 3 – severe pain: strong opioids

27. Less commonly used strong opioids
(covered in separate lecture)
• Fentanyl
• Oxycodone
• Hydromorphone
• Methadone

28. Morphine
• Adult starting dose: 2.5–20mg by mouth every 4 hours
depending on age, previous use of opiates, etc.
–Patients changing from regular administration of a
Step 2 opioid: 10mg by mouth every 4 hours
–If the patient has experienced weight loss from
sickness or has not progressed onto Step 2 analgesics:
5mg by mouth every 4 hours
–Frail or elderly patients: 2.5mg by mouth every 6 to 8
hours due to the likelihood of impaired renal function

29. • Morphine is available as immediate-release or sustained-release
formulations
• Immediate-release
–Dose every 4 hours
–Use to titrate starting dose and treat breakthrough pain
• Sustained-release (or slow-release)
–Dose every 8-24 hours, depending on the formulation
–After determining daily dose with immediate-release morphine, can
change to sustained-release morphine, being careful to adjust dose as
needed to maintain the total daily dose
• Priority should be given to making immediate-release formulations
available
Morphine
• Increase dose gradually until pain is controlled
• The correct morphine dose is the one that gives pain relief without side
effects: there is no ‘ceiling’ or maximum dose

30. Pethidine is not suitable for patients with chronic pain
• It has a faster onset of action and a shorter duration of action than
morphine and needs more frequent dosing: every 2–3 hours
• Pethidine is metabolised to norpethidine which has side effects
inducing central nervous system excitability including mood
changes, tremors, myoclonus (sudden jerking of the limbs) and
convulsions
• Pethidine was removed from the WHO essential medicines list in
2003 because it was judged to be inferior to morphine due to its
toxicity on the central nervous system and is generally more
expensive than morphine
Caution: pethidine

31. Treatment principles
• By the mouth: Use the oral route whenever possible
• By the clock: Administer analgesics according to regular schedule
based on duration of effectiveness rather than “as needed”, except
when titrating dose
• By the ladder: Use the WHO analgesic ladder. If after giving the
optimum dose an analgesic does not control pain, move up the
ladder; do not move sideways in the same level
• By the patient: The right dose is the one that relieves pain. Titrate
the dose upwards until pain is relieved or side effects prevent moving
up further

32. • When stopping an opioid, reduce daily dose by 25% each
day to avoid symptoms of withdrawal
• When changing from one opioid to another, be mindful
of the need to convert doses
–Check reference materials or consult an expert
–All patients on opioids are at high risk for constipation,
and laxatives should be ordered unless
contraindicated
Stopping or changing opioids

33. Adjuvant analgesics, which are also referred to as co-analgesics, are
medicines that are not primarily used for analgesia. These are
medicines that are administered alone or with NSAIDs and opioids that
may:
• Enhance the analgesic activity of the NSAIDs or opioids
• Have independent analgesic activity for certain pain types (such as
neuropathic pain)
• May counteract the side effects of NSAIDs or opioidsThe use of
adjuvants that target neuropathic pain may be particularly important
because such pain may be difficult to treat with opioids alone
• Adjuvants are also useful for other pains that are only partially sensitive to
opioids such as bone pain, smooth or skeletal muscle spasms, or pain related to
anxiety
Adjuvants or Co-analgesics

34. Antidepressants
Used for neuropathic pain, presenting primarily as burning or
abnormal sensations (dysaesthesia)
• Amitriptyline
–Adults: 10-75mg or 0.5-2mg/kg at night then increase
slowly as needed
–Commonly start at 12.5mg at night and then increase to
twice per day as needed
–Response should be evident within 5 days
• If no effect after 1 week, stop the drug

35. –Side-effects include dry mouth and drowsiness
–Use with caution in the elderly because it may increase
falls
–Use with caution in those with cardiac disease because
it may cause orthostatic hypertension
• Nortriptyline
–May be better tolerated than amitryptyline

36. Anticonvulsants
Use for neuropathic pain; check for drug interactions
• Clonazepam
– Adults: 0.5mg to 2mg once a day
• Carbamazepine
– Adults: start at 100mg twice a day and can be increased up to 800mg twice a day
• Sodium valproate
– Adults: 200 mg - 1.2g once a day
• Gabapentin
– Adults: start with 300mg at bedtime and titrate up every 2 or 3 days (300mg
twice per day, then three times per day) until effective or side effects occur
– Usual effective dose is 300-600mg three times a day (maximum dose 1200mg
three times per day)
– Decrease dose in patients with renal insufficiency

37. • Use Phenytoin and Carbamazepine with caution
because of the rapid metabolism of other drugs
metabolised in the liver and therefore potential drug
interactions
• Side effects: drowsiness, loss of muscle coordination
(ataxia) or blurring of vision

38. Antispasmodics
Use antispasmodics for muscle spasm, e.g. colicky
abdominal pain or renal colic
• Hyoscine butylbromide (Buscopan)
–Adults: start at 10mg three times a day; can be
increased to 40mg three times a day
• Antispasmodics can cause nausea, dry mouth, or
constipation

39. Muscle Relaxants
Use these drugs for skeletal muscle spasm and
anxiety-related pain
• Diazepam
–Adults: 5mg orally 2 or 3 times a day
• Lorazepam
–0.5-2mg oral or intravenous every 3 to 6 hours
• Side effects: can cause drowsiness and ataxia

40. Corticosteroids
Use corticosteroids for bone pain, neuropathic pain, headache due to raised
intracranial pressure, and pain associated with oedema and inflammation
• Dexamethasone
– Adults: 2–4mg per day for most situations
– For raised intracranial pressure, start at 24mg per day and reduce by 2mg
each day to the lowest effective maintenance dose
– For pain from nerve compression, start at 8mg
– For spinal cord compression, start at 16mg
• Prednisolone
– Use when dexamethasone is not available
– A conversion rate of 4mg Dexamethasone to 30mg Prednisolone can be
used

41. • In advanced disease, a corticosteroid may improve
appetite, decrease nausea and malaise, and improve
quality of life
• Side effects include neuropsychiatric syndromes,
gastrointestinal disturbances and
immunosuppression
• When stopping a corticosteroid, remember gradually
taper down the dose

42. Biphosphanates
Bisphosphonates are used for the treatment of cancer-
related bone pain
• Pamidronate- 60-90mg slow intravenous infusion
every 4 weeks
• Side effects
–Fever and flu-like weakness
–Osteonecrosis of the jaw, although rare, has been
associated with bisphosphonate therapy

43. • Co-analgesics are important complementary
medications in pain relief
• Used with the correct combinations, co-analgesics
can enhance analgesic effects
• Adjuvants are useful for neuropathic pain and other
pains that are only partially sensitive to opioids such
as bone pain, smooth or skeletal muscle spasms, or
pain related to anxiety

44. Side Effects
Know the peculiar side effects to this Drugs
Opioids, NSAIDS, Acetaminophen
The Adjuvants
Also know the antidotes for their overdosage

45. WHO analgesic ladder in
children
Only two steps
mild——-moderate or severe pain
Non opioids +/- adjuvant———- Strong
opioids plus step 1
No room for weak opioid

46. Other modalities for the treatment
of pain
Nerve block; peripheral and Neuraxial
• PCEA, Epidural analgesia
• Peripheral nerve blocks; brachial plexus, femoral nv
block, ankle block
• Field infiltration
• Note non-pharmacological approach; acupuncture,
TCNS etc .

47. • Include family in the process
• Provide written information and in clear writing,
enlarged as needed
• Anticipate pain and treat accordingly
• Titrate doses individually
–Start low and titrate upward slowly
• Use care with adjuvant co-analgesia to avoid drug
interactions and unwanted side effects
Managing pain in the elderly

48. • Most patients with sickle cell disease experience pain on a
daily basis
• Crisis pain: the most severe pain experienced by sickle cell
patients
–Patient feels that “all my bones are breaking”
–Reported to occur about 13% of all days
–Characterized by abrupt onset, episodic and
unpredictable, and with severe pain
–May last several hours to a week or more
Pain in sickle cell disease

49. • Patients may need chronic pain management and rescue
medication for acute pain crises
• Those with three or more pain crises per year are candidates for
hydroxyurea therapy, which significantly decreases their
occurrence
• Assess pain frequently and treat as an emergency
• Maintain adequate hydration
• Investigate other possible causes of pain, including complications
of the diseases (acute chest syndrome, priapism, splenic
sequestration, cholelithiasis)
• Do not withhold opioids when pain is severe: treat according to
the WHO analgesic ladder
• Some patients may require chronic use of opioids on a daily basis
to manage pain and improve function

50. • Use the oral route whenever possible
• Exceptions may be:
–Need for rapid pain relief in pain emergencies:
intravenous or subcutaneous route
–Oral route is not accessible: rectal, buccal, intravenous,
subcutaneous, nasogastric, or transdermal
–Check to see if dose conversion is needed to move from
oral to alternative route
• Avoid intramuscular injection: causes more pain
Alternative routes of administration

51. • Though chronic pain is common in the elderly,
pain can be assessed and managed, even for
those suffering from dementia
• Sickle cell pain should be assessed frequently
• Sickle cell crisis should be treated as an
emergency

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