- The document provides an overview of pain therapy and clinical aspects presented by Dr. L. S. Patil. - It discusses the goals of pain therapy, approaches to patients with pain including classification, measurement scales, and examination. - Types of pain like nociceptive and neuropathic pain are defined. Analgesic treatments like NSAIDs, opioids, and the WHO pain ladder are explained. - Management of chronic pain, use of TCAs, anticonvulsants, and opioids are covered. The role of a multidisciplinary team and various modalities are highlighted. Pain in palliative care is also addressed.

1. PAIN
THERAPY AND CLINICAL ASPECTS
GUIDE – DR. L. S. PATIL
PRESENTER – Dr. DEEPAK R. CHINAGI
BLDE UNIVERSITY'S SBMPMC, VIJAYAPURA
21-03-2017

2. Topics to be covered
• Goals of therapy
• Approach to a patient with pain
• Nociceptive pain and neuropathic pain
• NSAIDS
• Opioid analgesics
• Management of chronic pain
• WHO Pain Ladder
• TCAs and Anticonvulsants in the management of
Chronic Pain.
• Pain as palliative care

3. GOALS OF THERAPY
• The ideal treatment for any pain is to remove
the cause, and provide effective analgesia
• In certain painful conditions (post operative,
burns, cancer, trauma), analgesics are the first
line of treatment and hence practitioners
should be familiar with the use of analgesic.

4. Approach to a patient with Pain
• International association for the study of pain
Defined Pain as unpleasant sensory and
emotionla experience associated with actual
or potential tissue damage.
• Classification of pain according to etiology
– Physiological
– Inflammatory/Nociceptive
– Neuropathic
– Psychosomatic

5. • Classification by duration
– Acute
– Chronic
• A careful history will help in the diagnosis of
underlying condition
– History regarding site, distribution, character,
duration, rapidity of onset, severity of pain,
aggravating or relieving factors,

6. • A detailed examination about the relevant
systems involving musculoskeletal system , per
abdomen, cardiovascular and respiratory system
is made to find out the cause.
• An inflamed joint can be graded into following
classes
– Grade 1 : The patient says joint is tender
– Grade 2 : The patient winces with pain
– Grade 3 : The patient withdraws the affected part
– Grade 4 : The patient will not allow the joint to be
touched

7. • Measuring pain : Pain is a subjective
experience and hence difficult to quantify.
• Either single dimension scales or
Multidimension scales are used for
quantifying pain.

8. Single dimension scale
• Visual analogue scale:
– Patient is given a scale of 0 to 10 cm , with 0 being
no pain and 10 being the worst pain. And patient
is asked to rate on the scale.

9. Multi dimension scale
• Mc Gill Pain Questionnare
– Here multiple aspects of pain are analysed,
subjective quality of pain and emotiinal response
to pain.
– Divided into Sensory pain rating, Affective Pain
Rating, Visual Analogue scale and a sum of all 3
rating.
– Pain rating divides type of pain experienced into 3
grades(mild - 1, moderate - 2, severe - 3). Total
scores are added to get final pain score.

10. Nociceptive pain and Neuropathic pain
Note Nociceptive pain Neuropathic Pain
Description of pain Aching, Localized, tooth
like, sharp, Squuezing
Shooting, Radiating,
Satbbing, Burning, Electric ,
Shock-like
Movement impact Associated with movement Independent
Physical examination Normal response Allodynia, Hyperalgesia,
Vasomotor changes
Examples Injury, Post operative pain Peripheral neuropathy,
shingles, Cancer pain
Treatment strategies Conventional analgesics Conventional and non-
conventional
(antidepressants,
anticonvulsants)

11. NON STEROIDAL ANTI INFLAMMATORY
DRUGS (NSAIDS)
• These drugs are effective in cases of mild to
moderate headache and pain of musculo-
skeletal origin.
• These drugs block the effect of both COX 1
and COX 2 enzymes. Cyclooxygenase 1 has
protective role and action on gastro-intestinal
mucosa, renal and platelet function.
Cyclooxygenase 2 produces inflammatory
prostaglandins at the site of inflammation.

12. • COX 1 blockade is undesirable effect of
NSAIDs, which often leads to gastric irritation
and ulceration. (e.g. Aspirin)
• Aspirin irreversibly inhibits platelet Cyclo-
oxygenase, and interferes with platelet
aggregation, hence it is used for this purpose.
• NSAIDs also affect renal prostaglandin
synthesis at usual therapeutic dosage.

13. NSAIDs mediated renal injury
• Normally protective prostaglandins like PGE2
and PGI2 are secreted by the glomerulus in
response to glomerular hypoperfusion. These
prostaglandins act as vasodilators to maintain
renal perfusion. Due to blockade of
cyclooxygenase enzyme, these protective
prostaglandins are not synthesized.
• Acute hypovolemia or hypotension should not
receive NSAIDs.

14. Clinical aspects in the usage of NSAIDs
• For management of postoperative pain, COX2
selective inhibitors are useful. Non selective
COX inhibitors are contraindicated
postoperatively due to their unwanted effects
on gastric mucosa, platelet function.
• COX 2 inhibitors are associated with increased
risk of cardiovascular disease. Hence they are
used with caution in patients with risk factors
for cardiovascular disease.

15. OPIOID ANALGESICS
• These drugs act directly on the pain
transmission pathway by activating pain
inhibitory neuron. These drugs act on opiate
receptors that are extensively distributed in
brain and spinal cord as well as
gastrointestinal tract.
• There are five types of opiate receptors, delta
(DOR), kappa(KOR), mu(MOR), nociceptin
(NOR), zeta(ZOR). Most of the drugs act on mu
opiate receptor.

16. • These drugs are preferred for the control of
acute severe pain and provide rapid pain relief
by intravenous administration.
• Opioids are prone for respiratory
depression(sedation and decreased
respiratory rate). Hence close monitoring is
required to prevent life threatening
hypoxemia.
• Ventilator assistance is often required.

17. • Opioid antagonist Naloxone should be readily
available and used whenever high doses of
opioid are used or pulmonary function is
compromised.
• Pain Controlled Analgesia (PCA devices):
– It is a micropressor controlled infusion device that
can deliver a baseline continuous dose of an
opioid drug and additional doses as and when
required.
– It is used in management of post operative pain
and pain due to cancer

18. • PCA devices deliver a small bolus of drug (1mg
morphine or 0.2mg of hydromorphone or 10mcg
of fentanyl). These devices have LOCKOUT period
and dose limit per hour.
• New routes of administration: intrathecal
morphine(0.1-0.3mg) low dose is sufficient to
achieve required effect. This approach has been
used during labor and post operative pain. Other
routes of administration include intranasal,
transdermal and rectal route.

19. Morphine
• It was first isolated by Freidrich Sertuner in
1803 from plant source poppy. (Morphium =
Greek. God of Dreams)
• Pharmacokinetics : nearly 90 % of the drug is
meatbolised in liver and excreted by kidney.
• Half life : 2 to 3 hours, Duration of action 4 – 6
hours.
• It is considered in the WHO list of essential
drugs .

20. • It is used in the treatment of pain due to
myocardial infarction, cancer pain and post
operative pain control.
• Combination therapy : when opioids and COX
inhibitors are used in combination, synergistic
effect is seen and less chances of side effects.
• But the dose ratio combination can interfere
with the rate of metabolism and excretion of
each drug seperately.

21. WHO Analgesic Ladder

22. WHO Pain Ladder
• Step 1 : Mild to Moderate pain
– Non Opioids(NSAIDs) are recommended. Adjuvant as
antidepressant or anticonvulsant.
• Step 2 : Mild to Moderate pain not controlled by
Non Opioids
– Weak opioid is added(e.g. hydrocodone) , adjuvants
are continued.
• Step 3 : Moderate to Severe Pain
– When pain is inadequately controlled by first 2
approaches, a strong opioid is added. (e.g. Morphine ,
Oxycocodone)

23. Managing Chronic Pain
• Chronic Painful conditions like arthritis,
chronic headache, chronic back pain,
fibromyalgia, diabetic neuropathy and cancer
require evaluation to assess emotional and
organic factors before initiation of therapy.
• A multidisciplinary team is required for the
management. Few of the approaches are
counselling, physical therapy, nerve blocks and
surgery, epidural injection of glucocorticoids.

24. • Other modalities like spinal cord electrode
stimulation and intrathecal drug delivery
system also have shown significant benefit.
• These procedures are generally reserved for
those patients who do not get adequate
analgesia with pharmacotherapy.

25. Tricyclic Antidepressant in Chronic Pain
• These drugs are useful in the management of
chronic pain and provide relief of pain even at
the lower dosages that are used for treating
depression.
• These drugs potentiate opioid analgesia nad
are used as adjuvant in the management of
pain in cancer condition. They are also used to
treat neuropathic painful conditions.

26. • Indications :
– Post Herpetic Neuralgia
– Diabetic Neuropathy
– Tension Headache
– Migraine
– Rheumatoid Arthritis
– Chronic Low Back pain
– Cancer pain
– Central post stroke pain

27. • Side effects :
– Orthostatic Hypotension
– Drowsiness
– Cardiac Conduction Delay
– Memory impairment
– Constipation
– Urinary Retention

28. Anticonvulsants and Antiarrythmics
• These drugs are primarily used for treating
neuropathic pain with lancinating quality.
• Phenytoin and Carbamazepine are used for
the treatment of trigeminal neuralgia.
• Gabapentin and Pregabalin are also advocated
for the use in neuropathic pain.

29. Chronic Opioid Therapy
• Opioids provide prompt relief of pain, but their
use for long term treatment is deferred due to its
physical dependance.
• However the long term use of opioids in
malignant disease is accepted. But for the long
term use in non malignant conditions is
controversial.
• Some animal studies have shown that long term
opioid therapy may worsen pain in some
individuals

32. Pain in Palliative Care
• Nearly 30 to 90 % of advanced cancer patients
deal with pain, which occurs due to
mechanical and chemical stimulation of
nocicieptors.
• Interventions for pain in palliative care is done
by WHO pain ladder(3 step approach).
• NSAIDs : drug of choice in palliative care is
Ibuprofen 400mg q.i.d

33. • Weak opioids like codeine are used. Strong
opioids like morphine 5 – 10mg/ 4th hrly.
• Ideally an antiemetic is added with opioid
medication for initial week (e.g.
metoclopramide)

34. Thank You