1.pain and its management,lecture 1f,2 (2)

7/28/2019 1.Pain and Its Management,Lecture 1f,2 (2)

1/48

Dr muhu kahiga

Lecture 1


2/48


3/48


4/48

Pain - a highly unpleasant, individualizedexperience of one of the body's defensemechanisms indicating an injury or problem

Pain management - encompasses allinterventions used to understand and easepain, and, if possible, to alleviate the cause ofthe pain.


5/48


6/48

A pain message is transmitted to the CNS by

special PNS nerve cells called nociceptors. When a nociceptor is stimulated,

neurotransmitters are released within the cell.

The nociceptor transmits its signal to nerve

cells within the spinal cord, which conveysthe pain message to the thalamus.

Once the brain has received and processedthe pain message and coordinated anappropriate response, pain has served itspurpose.


7/48

Touch, pain, and temperature pathways from the trunk and limbs


8/48

The body uses natural painkillers, calledendorphins, to derail further pain messagesfrom the same source.

However, these natural painkillers may notadequately dampen a continuing painmessage.

Also, depending on how the brain has

processed the pain information, certainhormones such as prostaglandins may bereleased.


9/48


10/48

Based on duration-Acute pain and chronicpain.

Based on pathologic state-Inflammatory painand Neuropathic pain

Based on speed of onset, intensity & location-Fast pain(bright, sharp, localized )

slow pain (dull, intense, diffuse,& unpleasant)


11/48

Afunction of nociceptors Response to acute pain is made by the

sympathetic nervous system.

Associated with injury, headaches, disease,

and many other conditions. It normally resolves once the condition that

precipitated it is resolved.


12/48

Response a function of the parasympatheticnervous system

Time limit-ranges from three to six months

Considered as pain that endures beyond a

normal healing time. e.g. pain associated with cancer; persistent

and degenerative conditions; and neuropathy,or nerve damage, unremitting pain such as

low back pain


13/48

This is divided into 3 phasesAcute inflammation-is the initial response to

injury and is mediated by autocoidseg,histamine,serotonin,bradykinin,Prostagladins,leulotrienes

Immune response-occurs when foreignsubstances or antigens activate an immune

reaction


14/48

Chronic inflammation-involves release ofmediators eg,interleukin,1,2,3,Granulocyte-macophage colony stimulating factor,tumornecrosing factor or platelet derived growth

factors

Usually outcome is negative because it doesnot lead to resolution of the injury eg inrheumatoid arthritis


15/48


16/48


17/48

Clinicians often take what is called a pain

history. A typical pain history includes the following

questions:

-Where is the pain located?

-On a scale of 1 to 10, with 1 indicating theleast pain, how would the person rate thepain being experienced?


18/48


19/48


20/48


21/48

-What does the pain feel like?

-When did (or does) the pain start?-How long has the person had it?

-Is the person sometimes free of pain?

-Does the person know of anything thattriggers the pain, or makes it worse?

-Does the person have other symptoms(nausea, dizziness, blurred vision, etc.)

during or after the pain?


22/48


23/48

-What pain medications or other measures hasthe person found to help in easing the pain?

-How does the pain affect the person's ability

to carry on normal activities?

-What does it mean to the person that he or

she is experiencing pain?


24/48


25/48


26/48

Considers the different causes and types of

pain, as well as its nature and intensity.

Management can require an interdisciplinaryapproach.

The elements of this approach includetreating the underlying cause of pain with:-

-non-pharmacological therapies

- pharmacological therapies

-invasive (surgical) procedures.


27/48

Relaxation techniques such as yoga andmeditation are used to focus the brainelsewhere than on the pain it decreasesmuscle tension, and reduce stress.

Regular exercise has been linked toproduction of endorphins, the body's naturalpainkillers.

Acupuncture involves the insertion of small

needles into the skin at key points.


28/48

Acupressure uses these same key points, but

involves applying pressure rather thaninserting needles.

Applying heat or massage are very relaxingand help reduce stress.

Transcutaneous electrical nerve stimulation(TENS) applies a small electric current tocertain parts of nerves, potentially

interrupting pain signals and inducing releaseof endorphins.


29/48

The Three-Step Ladder approach

Mild pain is alleviated withacetaminophen/Paracetamol or anonsteroidal anti-inflammatory drug (NSAID).

These drugs are used to treat pain from

inflammation and work by blockingproduction of pain-enhancingneurotransmitters.

NSAIDs and acetaminophen are effective formost forms of acute pain.


30/48

Mild to moderate pain is eased with a milder

opioid medication, plusacetaminophen/Paracetamol or NSAIDs. Opioids are both actual opiate drugs such as

morphine and codeine, and synthetic drugs

based on the structure of opium. This includes drugs such as oxy-codon,

methadone, and meperidine.

They provide pain relief by binding to specificopioid receptors in the brain and spinal cord.


31/48

Moderate to severe pain is treated withstronger opioid drugs, plusacetaminophen/Paracetamol or NSAIDs. Morphine is sometimes referred to as the

gold standard of palliative care

-It is not expensive-can be given by starting with smaller doses

and gradually increased

-is highly effective over a long period of time.

-can also be given by different routes


32/48

Propionic acid derivatives----ibuprofen Pyrroleakanoic acid derivativestolmentin Phenylalkanoic acid derivativesflubiprofen Indole derivative-----indomethacin Pyrazolone derivatives---phenylbutazone Phenylacetic acid derivative---diclofenac Fenamates-mefenamic acid Oxicams------piroxicam Napthylacetic acid prodrug--------

nabumetone


33/48


34/48

These are agents that are used in

combination with those discussed above.

They improve the outcome of management

They are mainly:-

-Antidepressants

-Anticonvulsants


35/48

Although antidepressant drugs were

developed to treat depression, it has beendiscovered that they are also effective in:-

-combating chronic headaches

-cancer pain

-pain associated with nerve damage.

Antidepressants that have been shown tohave analgesic (pain-reducing) properties

include amitriptyline, trazodone,andimipramine.


36/48

Anticonvulsant drugs share a similar

background with antidepressants. Developed to treat epilepsy, anticonvulsants

were found to relieve pain as well.

Drugs such as phenytoin and carbamazepineare prescribed to treat the pain associatedwith nerve damage e.g trigeminal neuralgia,neuralgia in herpes zoster ...


37/48

WHO THREE STEP ANALGESIC LADDER

Increasing level of pain

Aspirin

NSAIDs

ParacetamolAdjuvants

Codeine

Oxycodeine

Dihydrocodeine

Tramadol

Adjuvants

Morphine

Hydromorphine

Methadone

Fentanyl

Oxycodone

Adjuvants

Step 1Mild pain

Step 2Moderate pain

Step 3Severe pain

0 100


38/48


39/48

An effective alternative to aspirin.

Antipyretic activity comes from its directaction on the hypothalamic heat-regulatingcenter to increase the dissipation of heatthrough increased vasodilation and

perspiration. Analgesic activity is mediated through

prostaglandin (PG) inhibition in the centralnervous system (CNS).

Its lack of peripheral PG inhibition makes it aweak anti-inflammatory agent.


40/48

Acetaminophen/Paracetamol is almost

completely absorbed from the GI tract andthus has an onset of action ranging from 30to 45 minutes.

Its extensive liver metabolism to inactive

substances makes it a relatively nontoxicagent.

A small portion (4%) of the drug is convertedto a toxic metabolite, normally inactivated by

glutathione pathways.


41/48

The NSAIDs are divided into a variety of

chemical classes.

All NSAIDs have anti-inflammatory, analgesic,and antipyretic activity because of their abilityto inhibit cyclooxygenase, an enzymenecessary for PG synthesis.


42/48

All NSAIDs are highly protein bound.

Lower doses should be used in elderlypatients.

A significant analgesic effect is achievedwithin 1 hour of NSAID administration, with

maximaleffects within 2 or 3 hours.

Long-term use of NSAIDs at high doses (anti-inflammatory doses) can cause seriousadverse effects.


43/48

The most common, potentially serious sideeffects are those affecting the kidney and GItract.

The newer COX-2 inhibitors have less GI

toxicity; however, risk for renal adverseevents is similar to traditional NSAIDs.

Indomethacin is associated with more CNSadverse effects than other NSAIDs.


44/48

Opioids bind to one of the four opiate

receptors: mu, kappa , sigma , or delta. Agonists: morphine, hydrocodone,

hydromorphone, levorphanol , fentanyl,methadone , meperidine, propoxyphene ,

codeine, and oxycodone. Partial agonistantagonist:Pentazocine ,

butorphanol, buprenorphine , dezocine

and nalbuphine.


45/48

Opioid Antagonists:Naloxone and naltrexone These are pure opioid antagonists that

competitively bind to all opioid receptors

without producing an analgesic response.


46/48

Tramadol, a centrally acting, non-narcoticagent.

Chemically unrelated to both the opiates andthe NSAIDs.

Low risk of abuse and tolerance

Indicated for moderate to moderately severepain.


47/48

Side effects common to all opioids include

sedation, euphoria,and GI disturbances. The GI disturbances are primarily

constipation and nausea.

Although considered the most dangerous

side effect, severe respiratory depressionisrarely seen in patients without underlyingpulmonary dysfunction.


48/48

NonPharmacological Interventions

Paracetamol1g four times

daily(Optimize

dose)

NSAIDs-(optimizedose)

Mild opiodsDihydrocodeine

Codeine

diphosphate

Tramadol

StrongOpiodsMorphine

Fentanyl

Oxycodone

Take Home Message

1.pain and its management,lecture 1f,2 (2)

Documents