Pain management in cancer

PAIN MANAGEMENT IN CANCER

• Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage

• Somatopsychic phenomenon modulated by

Patients moodPatients moraleMeaning of pain for the patient

• 75% of advanced cancer patients experience pain

• One third has single pain• One third has 2 pain• One third has 3 or more pain

pain

psychological

Spiritual

Social

Physical

PAIN MANAGEMENT

• Evaluation• Multidimensional process

• Begins with locating the pain• ‘where exactly is your pain?’• Duration

Characteristics

• Palliative factors• Provocative factors• Quality• Radiation• Severity• Temporal factors

Causes of pain

• Cancer

• Treatment-mucositis

• Debility-constipation, muscle tension

• Concurrent disorder-spondylosis, osteoarthritis

Mechanism

• Functional• Somatic muscle tension pains-tension head

ache, cramp• Visceral-distension, colic

• Pathological• Nocioceptive-tissue distortion or injury

• Neuropathic-compression or injury

• Causes • Cancer-

nerve compression or infiltrationPlexopathySpinal cord compressionThalamic tumor

• Treatment-surgical incision pain phantom limb pain

peripheral neuropathy brachial plexopathy

• Debility-post herpetic neuralgia

• Concurrent disorder-diabetic neuropathy, post stroke pain

AGGREVATING FACTORS

• Discomfort boredom• Insomnia mental isolation• Fatigue social abandonment• Anxiety• Fear • Anger• Sadness• depression

DECREASED• Relief of other symptoms • Sleep • Understanding• Companionship• Creative activity• Relaxation• reduction in anxiety• elevation of mood• drugs

managementModification of

pathological process

analgesics

Non-drug methods

psychological

Interruption of pain pathways

Modification of way of life and

environment

• Modification of pathological process-Radiation therapyHormone therapyChemotherapysurgery

Non-drug methods-massage, heat pads

Psychological-relaxation, cognitive behavioral therapy,

• Interruption of pain pathways local anaesthesia neurolysis-chemical(alcohol, phenol)

cryotherapy thermocoagulation

neurosurgery-cervical cordotomy

• Modification of way of life and environment• Avoid precipitating activity• Immobilisation of painful part-cervical collar,

slings, surgery• Walking aid

ANALGESICS

• Non-opioid• Opioid• Adjuvant

• Principles governing the analgesic use• By the mouth• By the clock-persistent pain needs preventive

therapy• By the ladder-if after optimising the dose of

drug fails to relieve, move up the ladder• Individualised treatment-right dose is the one

which relieve the pain• Use of adjuvant drugs-relieve pain in specific

situation

Strong opioid+non-opioid±adjuvant

Weak opioid+non-opioid±adjuvant

Non-opioid ±adjuvant

Non opioidParacetamol,NSAID

OpioidsCodeine(weak)

Morphine(strong)

AdjuvantSteroids, anti

depressants, anti-epileptics, anti-

spasmodics, muscle relaxants

NON-OPIOID ANALGESICS

• Paracetamol n NSAIDs• Paracetamol-anti-pyretic analgesic inhibits

COX in CNS• Lack anti-inflammatory effect• Undesirable effect uncommon• Does not cause gastritis• Does not affect plasma uric acid• No effect on platelet function

NSAIDs

• Pain associated with inflammation-soft tissue infiltration, bone metastasis

• Non selective Inhibition of COX

• Its prolog use is limited by its adverse effect

• Gastritis• Antoganise urocosuric drugs• Salt and water retension• Renal failure and interstitial nephritis• Platelet dysfunction• Aspirin may cause tinnitus and deafness

WEAK OPIOIDS

• Codeine, dextroprpoxyphene, dihydrocodeine, tramadol

• Codeine is 1/10 as potent as morphine• More constipating than morphine• Tramadol is 1/10 to 1/5 as potent as morphine• Dual mechanism of action partly via opioid

receptor partly by inhibiting PRE SYNAPTIC reuptake of 5-HT and NA

• Less constipating• More effective in neuropathic pain than

morphine• Lower seizure threshold• TCA and SSRIs

Strong opiods

• Morphine, dimorphine, methadone• Oral morphine(tablets and aqeous solution)

• Guidelines for starting morphine

• Indicated in patients in patients who does not respond to optimised combined use of non-opioid and weak opioid

• Start with 10mg q4h or m/r 20-30mg q12h

• Lower dose 5mg q4h in elderly and frail and in renal failure

• If patients requires two or more p.r.n dose in 24h increase dose by 30-50% every 2-3 days

• Titrate till pain relieves or intolerable effects limits further escalation

• Add drugs which relieves its adverse effects

• Anti emetic haloperidol 1.5mg stat and sos, metaclopramide

• Prophylactically prescribe laxative to prevent constipation

• Warn all patients about initial drowsiness

• For outpatients write out drug regimen in detail time, amount to be taken and arrange for follow up

• Ordinary morphine and modified release morphine(m/r)

• Once we get the stable q4h ordinary morphine dose

• Replace it with q12h m/r morphine(3 times q4h dose)

• Continue to give p.r.n ordinary morphine 1/6 th of total daily m/r dose

Adverse effects

• Gastric stasis- epigastric fullness, flatulence, nausea, anorexia, hiccup-metoclopramide

• Sedation• Cognitive failure-haloperidol

• Myoclonus and Hyperexcitability -abdominal muscle cramps, whole body allodynia, symmetrical jerking of pain

• Vestibular stimulation- movement induced nausea and vomiting

• Pruritus-ondansetron

• Histamine release- broncho constriction

• Dimorphine• More soluble than morphine• Large amount can be in small volume• It is used instead of morphine when injections

are necessary• Twice as potent as morphine in iv

Alternative strong opioids

• buprenorphine• fentanyl• hydromorphone• methadone• Oxycodone these are used when patients are intolerant

to morphine

Indication of methadone-• Severe intolerable side effects with morphine

at any dose• Severe pain despite increasingly high doses• Neuropathic pain not responding to typical

regimen of NSAIDs, morphine, TCA and valproate

• Renal failure

• Stop morphine abruptly

• 1/10 dose of 24h oral morphine up to maximum 30 mg

• Allow the patient to take the dose in q3h p.r.n

• On day6 amount of methadone taken over previous 2 days is converted into regular q12h dose

• If p.r.n dose is still neededincrease the dose of methadone by 1/3-1/2 every 4-6 days

• 2nd scheme• Stop morphine abruptly

• 5-10mg methadone q4h and q1h p.r.n

• After12-24h if frequent p.r.n dose is needed

• 10-15mg and q1h p.r.n

• After 72 h convert to q8h and q3h p.r.n

• Increase the dose every 4-5 days

ADJUVANT ANALGESICS

• They are add on drugs supplementing the impact of NSAIDs and opioids

• Its main use is in neuropathic pain

CLASS INDICATIONS

MOA EXAMPLE TYPICAL REGIMEN

ADVERSE EFFECTS

STEROIDS Nerve compression

Reduce peri tomor edema

Prednisolonedexamethasone

15-30mg om8-16 mg o.m

Hyperglycemia,anxiety,steroid psychosis

ANTIDEPRESSANTS

Nerve injury pain

Potentiation of GABA inhibition

Amitriptylineimipramine

25-100 o.n

Antimuscarinis effects,drowsiness,

ANTI EPILEPTIC

Nerve injury pain

Potentiation of GABA inhibition

Valproate

gabapentine

400-1000mg o.n100-300mg tds

drowsiness

NMDA RECEPTOR CHANNEL BLOCKER

Pain poorly responding to analgesics

Nmda receptor block

Methadone

ketamine

10-60mg bd

10-20mg q6h

Drowsiness

dysphoria

Anti spasmodics

Bowel colic Relax smooth muscles

Hyoscine 60-160mg/24h sc

Peripheral anti muscarinic effect

Muscle relaxants

Muscle spasm

Relax somatic muscle

baclofen 10mg tds

bisphosphonates

Metastatic bone pain

Osteoclastic inhibition

Zolendronic acid

4mg every 4-8 week

pyrexia

• ADJUVANT ANALGESICS FOR NEUROPATHIC PAIN

• STEP1-CorticosteroidsT• STEP2-TCA or anti EPILEPTICS

• STEP3-TCA and anti EPILEPTICS

• STEP4-NMDA receptor blocker

• STEP5-Spinal analgesia

ALTERNATIVE ROUTES OF ADMINISRATION

• Dispersible tablets

• Liquids or sprinkling

• Sublingual tablets or suppository or transdermal patch

• Injections

Continuous SC infusions

• Battery driven portable syringe drivers

• Useful in patients with severe nausea and vomiting who cannot swallow drug due to various reason

• Upper chest, upper arm, abdomen, thighs-sites for infusion

• Advantages

• Better control of nausea and vomiting

• Constant analgesia

• Minimum no of injections

• Does not limit mobility

Topical morphine

• 0.1% gel• Pain associated with Cutaneous ulceration

• Oral mucositis

• Vaginal inflammation associated with fistula

• Rectal ulceration

Spinal morphine

• Epidurally or intrathecally

• Much lower dose with greater analgesic effect

• Intractable pain inspite of standard and adjuvant treatment