Pain

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Pain

An unpleasant sensory and emotional

experience associated with actual or

potential tissue damage, or described in

terms of such damage.

International Association for the Study of Pain

MYTHS

“Anesthetics mask symptoms”

“Patient will harm itself if there’s no pain”

“Pain is difficult to assess”

The Truth!

• Pain is BAD:

– Decreased cardiovascular function

– Decresed appetite

– Slows wound healing

– Decreased immune function

• Greater chance of infection

– Increased fear and anxiety

از لحاظ فیزیولوژیک درد چهار مرحله دارد

• STIMULATION ( تحریک)

• TRANSMISSION ( انتقال)

• PERCEPTION ( درک)

• MODULATION (متعادل کردن درد)

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Mechanism

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Process #2—Transmission

• Impulse spinal cord brain stem

thalamus central structures of brain pain

is processed.

• Neurotransmitters are needed to continue the

pain impulse from the spinal cord to the

brain—opioids (narcotics) are effective

analgesics because they block the release of

neurotransmitters

Process #4—Modulation of Pain• Changing or inhibiting pain impulses in the

descending tract (brain spinal cord)

• Descending fibers also release substances such as norepinephrine and serotonin (referred to as endogenous opioids or endorphins) which have the capability of inhibiting the transmission of noxious stimuli. Helps explain wide variations of pain among people.

• Cancer pain responds to antidepressants which interfere with the reuptake of serotonin and norepinephrine which increases their availability to inhibit noxious stimuli.

Process #3—Perception of Pain

• The end result of the neural activity of pain

transmission

• It is believed pain perception occurs in the cortical

structures—behavioral strategies and therapy can be

applied to reduce pain. Brain can accommodate a

limited number of signals—distraction, imagery,

relaxation signals may get through the gate, leaving

limited signals (such as pain) to be transmitted to the

higher structures.

Nociceptive Neuropathic

-soft tissue

-bone

-skeletal muscle

-smooth muscle

Nerve

Compression

Nerve

Injury

Classification of Chronic Pain

تفاوتهای این دو نوع درد

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Nociceptiveدردای دردای وريپاتیک

گب سبثق ضرث یب آسیت )آسیت ث اعػبة جد دارد اهب گب یچ سبثق ای وی تاى

(یبفت

آسیت ث ثبفت ثذىعلت درد(عضل، استخاى یبپست)

درد هجن ک هکبى آى یس هجن است حبلت ثرق گرفتگی سزش یب از ایي دست دارد

درد تیس ثب هکبى هطخع مشخصات دردضذیذ

ثسیبر هطکلداربی ضذ غرع ضذ افسردگی س حلق

ای

پبسخ ث درهبى هبست استNSAID ب ، استبهیفي

هخذربدرمان

رپبتی دیبثتیدرد ثعذ از یرس رپسدردبی هسهي ثعذ از عول

درد پطت

مثالاستئ آرتریت

Classification of Pain

Acute Chronic

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Postoperative pain can be divided into:

Acute pain is experienced immediately after

surgery (up to 7 days)

Pain which lasts more than 3 months after the

injury is considered to be chronic pain

مقایسه دو نوع درد

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درد حاددرد مسمهرایی از دردبسیار خشایىذبسیار خشایىذ

مقايمت ي يابستگی ب دارياوادرشایع

مشکالت ريحی ي رياویوادرشایع

علت بذوی ي فیسیکی ياضحاغلب مجد استعمما يجد وذارد

درگیری محیط ي خاوادبسیار واچیس استکامال بارز است

بی خابیوادریک جس تقریبا ثابت است

اذاف درماویدرمان قطعی درد ي بیماری زمیى ایببد فعالیت

افسردگیوادرشایع

―Describing pain only in terms of its

intensity is like describing music only

in terms of its loudness‖

von Baeyer CL; Pain Research and Management 11(3) 2006; p.157-162

PAIN HISTORY

• Description: severity, quality, location,frequency,

aggravating & alleviating factors

• Previous history

• Context: social, cultural, emotional, spiritual

factors

Patient

Assessment

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Treatment

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Treatment

• Non-pharmacologic

• Pharmacologic

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Non-Pharmacologic

• Stimulation Therapy:

– electrical nerve stimulation

• Psychological Intervention

– relaxation training, and hypnosis, have proven

effective in the management of postprocedure pain

and in cancer-related pain

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Pharmacologic Therapy

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General Treatment Principles

• In general, common causes of treatment failure

is Under-dosing

• When treating chronic pain, elimination and

prevention of pain is best accomplished by

using analgesics at fixed time intervals rather

than on an as-needed basis

• Effective analgesic therapy begins with an

accurate assessment of the patient

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+/- adjuvant

Non-opioid

Weak opioid

Strong opioidBy the

Clock

W.H.O. ANALGESIC LADDER

+/- adjuvant

+/- adjuvant

1

2

3

Guidelines for Cancer pain

The WHO 3-step Analgesic Ladder

Strong opioid

+non opioids+ adjuvants

Weak opioid

+non opioid

+ adjuvants

Non opioid

(antipyretic)

+ adjuvants

Pain

Pain persisting or

increasing

Pain persisting or

increasing

Step 1.

Step 2.

Step 3.

90% respond well to oral medicines

Adjuvant Analgesics

• first developed for non-analgesic indications

• subsequently found to have analgesic activity in specific

pain scenarios

• Common uses:

– pain poorly-responsive to opioids (eg. neuropathic

pain), or

– with intentions of lowering the total opioid dose and

thereby mitigate opioid side effects.

Adjuvants Used In Palliative Care

• General / Non-specific– corticosteroids– cannabinoids (not yet commonly used for pain)

• Neuropathic Pain– gabapentin– antidepressants– ketamine– topiramate– Clonidine– Pregabaline

• Bone Pain– bisphosphonates– (calcitonin)

inflammation

edema

spontaneous nerve depolarization

tumor mass

effects

CORTICOSTEROIDS AS ADJUVANTS

}

Steroids: MOA

inhibit phospholipase A2>>>

inhibits prostoglandin/leukotrienes

Membrane Phospholipid

Arachidonic Acid

“Bad” Prostaglandins

Pain/Inflammation

“Good” Prostaglandins

GI Protection

Renal Blood Flow

Thromboxane

“Platelets”

COX-2

COX-1

Phospholipase A2 Steroids inhibit here

NSAIDS inhibit here

Pain Level

Description

Numerical

Rating (0 to

10 Scale)

WHO Therapeutic

Recommendations

Example Medicines for

Initial Therapy

―Mild‖ pain 1–3

Nonopioid analgesic: taken

on a regular schedule, not as

needed (prn)

•Acetaminophen 650 mg

every 4 hr

•Acetaminophen 1,000 mg

every 6 hr

•Ibuprofen 600 mg every 6

hr

―Moderate‖ pain 4–6

Add opioid for moderate pain

(e.g., moderate potency

analgesic). Use on a

schedule, not prn

•Acetaminophen 325

mg/codeine 60 mg every 4 hr

•Acetaminophen 325

mg/Oxycodone 5 mg every 4

hr

•Tramadol 50 mg every 6 hr

―Severe‖ pain 7–10

Switch to a high potency

(strong) opioid; administer

on a regular schedule

•Morphine 15 mg every 4 hr

•Hydromorphone 4 mg every

4 hr

•Morphine controlled release

60 mg every 8 hr

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Dosing

• The management of chronic pain is also best

accomplished by around-the-clock

administration

• As-needed schedules are to be used in

conjunction with around-the-clock regimens

and are used when patients experience

breakthrough pain

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TOLERANCE

physiological phenomenon normalA

in which increasing doses are required

to produce the same effect

3.2.4: Chapter 1993Oxford Textbook of Palliative Medicine Inturrisi C, Hanks G.

PHYSICAL DEPENDENCE

physiological phenomenon in normalA

which a withdrawal syndrome occurs

when an opioid is abruptly discontinued

or an opioid antagonist is administered

3.2.4: Chapter 1993Oxford Textbook of Palliative Medicine Inturrisi C, Hanks G.

PSYCHOLOGICAL DEPENDENCEand ADDICTION

A pattern of drug use characterized by a

continued craving for an opioid which is

manifest as compulsive drug-seeking

behaviour leading to an overwhelming

involvement in the use and procurement

of the drug

3.2.4: Chapter 1993Oxford Textbook of Palliative Medicine Inturrisi C, Hanks G.

میلي گرم هروئین 60

دو هفته

ساعت بعد از آخرین مصرف 12

احساس ضعف

خمیازه

لرز

عرق

عطسه

ترشحات

موقع بیداري

ساعت 24تا 18

عمق جهنم

وابستگي

روز 7-8ترک

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Type of Pain Nonopioids Opioids Other

Medications Comments

Chronic low

back pain

Acetaminophen,

NSAIDs

Short-term use for

mild-to-moderate

flare-ups

TCAs, AEDs

Acetaminophen and

NSAIDS first; opioids in

selected patients; AEDs or

TCAs if neuropathic

symptoms

Fibromyalgia Acetaminophen,

NSAIDs

Long-term use not

recommended

Tramadol,

TCAs; AEDs

Acetaminophen and

NSAIDs considered first;

tramadol may be better

alternative than opioids

Neuropathic

pain

Acetaminophen

or NSAIDs are

rarely effective

Considered first-

line therapy but

usually are tried

after AEDs and/ or

TCAs, tramadol,

lidocaine 5% patch

TCAs, AEDs,

SNRIs, trama

dol, topical

(e.g., 5% lido

caine patch,

capsaicin)

Gabapentin, 5% lidocaine

patch, tramadol, nortrip

tyline, desipramine, all

considered first-line agents;

opioids considered first-line

agents but usually are tried

after above

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نام دارو دوز رایج حداکثر دوز عوارض توضیحات

Acetaminophen

Tynelol®

Panadol®

هیلی گرم ر 1000الی 500سبعت یب 4ر 650الی 325سبعت 6 4000

عبرض کجذی در غرت هسوهیت

Mefenamic acid

Ponstan®سبعت 6هیلی گرم ر 250هیلی گرم سپس 500اثتذا 1000

اثر ثیطتر ثری اعقبد خى

سبل تغی وی ضد 14ثرای زیر حذاکثر تب یک فت هػرف ضد

Naproxen

Aleve®

6ر 250سبعت یب 12ر 500هیلی گرم سپس 500اثتذا سبعت 8تب 1000

Ibuprofen

Advil®

سبعت 8الی 6هیلی گرم ر 400الی 200سبعت 8هیلی گرم ر OTC 400ث طر

هیلی گرم ث ازای ر کیل زى ثذى 10الی 5دز اطفبل سبعت 8تب 6ر

32001200

حذاکثر دز ثرای هػرف

OTCثطر

کن عبررض تریي NSAID

هب 6ایي دار ثتر است در اطفبل زیر استفبد طد

Celecoxib

Celebrex®

Cobix®

یک ثبر در رز 200د ثب در رز یب 100 200

احتوبل ایجبد هطکالت قلجی

تبخیر در ترهین استخاى

ثبعث 200افسایص دز هػرفی از افسایص هطکالت قلجی عرقی هیطد

Diclofenac

Voltaren®

سبعت 8الی 6هیلی گرم ر 50تب 25هیلی گرم از فرآرد آست رص یک تب حذاکثر د 100

ثبر در رز200

ضیع ثیطتر عبرض کجذی

Indomethacin

Indocin®

یس دز را 150ثبر هی تاى تب رزا 3الی 2رزی 25افسایص داد

عذد 2قرظ آست رص را هی تاى رز ییک تب سبعت 6ر 25در حوالت حبد قرس

150پر عبرض تریي

NSAIDعارؼ عػجی

Tolmetin سبعت 8هیلی گرم ر 400تب 200 1800

Meloxicam

Mobic®هیلی گرم یک ثبر در رز 15تب 7.5 15

ثیطتریي عارؼ پستی

ترکیجبت هبر کذ اختػبغی هطبث COX2

Piroxicam

feldene ®

هیلی گرم رزی یک 20ثبر در رز یب 2هیلی گرم 10ثبر

ثیطتریي عارؼ پستی

ث علت طل اثر ثلذ، اثر کبهل آى ضبیذ ثعذ از یک فت ظبر ضد

Patient Control Analgesia (PCA)

Treatment of Neuropathic Pain

Pharmacologic treatment

• Opioids

• Steroids

• Anticonvulsants – gabapentin, topiramate

• TCAs (for dysesthetic pain, esp. if depression)

• NMDA receptor antagonists: ketamine, methadone

• Anesthetics

Radiation therapy

Interventional treatment

• Spinal analgesia

• Nerve blocks

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