lesson 4 analgesics

7/27/2019 Lesson 4 Analgesics

http://slidepdf.com/reader/full/lesson-4-analgesics 1/49

Analgesics andAntipyretics



Pain

When nerve signals are sent to thebrain (CNS) after feeling a hurtfulsensation inside or outside the body,

the brain perceives these signals aspain.

When the client complains of pain, it isimportant for the nurse to treat it.

Pain: the fifth vital sign



Pain Transmission

Tissue injury causes the release of:

Bradykinin

Histamine

Prostaglandins Serotonin

These substances stimulate nerve endings,starting the pain process.



Pain Transmission Gate Theory

Most common and well-described theoryof pain

Uses the analogy of a gate to describe

how impulses from injured tissues aresensed in the brain



Pain Transmission in theSpinal Cord

A fibers

Myelin sheath

Large fiber size

Conduct quickly

Sharp and well-localized

C fibers

No myelin sheath

Small fiber size

Conduct slowly

Dull andnonlocalized



Neurotransmitters

Body has endogenousneurotransmitters

Endorphins

Enkephalins

Produced by body to fight pain

Marathon runners and cyclists

Bind to opioid receptors

Inhibit transmission of pain by closingthe gate



Management of Pain

Treat the cause.

Select a safe analgesic.

Select the analgesic that provideseffective relief.

Provide psychological support.

Nursing actions: position change

and back rub



Analgesics

Analgesic drugs relieve pain withoutcausing loss of consciousness.



Opioid Analgesics

Opium has been used for thousands of years to alleviate pain.

Opium is derived from the poppy plant.

Opium produces pain relief by attachingto pain receptors.

Narcotics are derivatives of opium.

Narcotics are strong pain relievers.



Classifications of OpioidAnalgesics

Classifications based on their actions:

Agonist

Agonist-antagonist

Partial agonist



Uses for Opioid Analgesics

Main use: to alleviate moderate to severepain

Opioids are also used for:

Cough suppression

Diarrhea treatment



Effects of Opioid Analgesics

Euphoria

Nausea and vomiting

Respiratory depression

Urinary retention

Diaphoresis and flushing

Pupil constriction (miosis)

Constipation



Complications of OpioidAnalgesics

Respiratory implications

Constipation concerns



Opioid Analgesics:Nursing Assessments

Perform a thorough history.

Obtain baseline vital signs andassessments.

Assess for potential contraindicationsand drug interactions.



Opiates: Opioid Tolerance

A common response to chronic opioidtreatment

Larger dose of opioids is required



Opiates: PhysicalDependence

Physiologic adaptation to the presenceof an opioid

If in need of pain relief, give the

medication



Opiates: PsychologicalDependence (Addiction)

A pattern of compulsive drug use whenthe medication is not needed for physicalpain relief



Opioid Analgesics:Nursing Implications

Law: narcotics must be kept under adouble lock

(continues)




Pain management approaches

Medical/nursing Medicate clients before a procedure or an

activity and/or When they are complaining of pain

Nursing Back rub, musical therapy, and relaxation

therapy

(continued)



Opioid Analgesics:Therapeutic Effects

Monitor for therapeutic effects

Increased comfort

Activities of daily living improved



Opiate Antagonists

Naloxone (Narcan) and naltrexone(ReVia)

Opiate antagonists

Bind to opiate receptors and prevent aresponse

Used for reversal of opioid-inducedrespiratory depression




Rotate site for IM injections.

Follow proper guidelines for IVadministration, such as dilution and rateof administration.

Check dosages carefully.

(continues)




Prevent constipation. Provide fluid and fiber.

Prevent respiratory depression.

Provide instruction for clients. Drug administration

Position changes

(continued)



Analgesic Agents

Analgesic agents

Salicylates (ASA)

Acetaminophen (Tylenol)

Combination narcotic and non-narcoticanalgesics

Anti-inflammatory analgesic agents

Nonsteroidal anti-inflammatory drugs(NSAIDs)



ASA (Acetylsalicylic Acid)

Used for more than 100 years

Action: peripherally interferes withsynthesis of prostaglandins andchemical substances released frominjured tissue

Treats mild to moderate pain

Antipyretic effect



ASA: Side Effects

Gastrointestinal irritation and bleeding

Increases bleeding time

Tinnitus

Children: Reye’s syndrome



Analgesic Agents:Acetaminophen

Mechanism of action

Blocks pain impulses peripherally Relieves pain

Reduces a fever –

antipyretic Weak anti-inflammatory

Minimal effect on the central nervous system



Acetaminophen: Side Effects

Acute overdose causes hepaticnecrosis.

Doses of 150 mg/kg Long-term ingestion of large doses can result in

nephropathy



Acetaminophen: AcuteOverdose

Treatment: acetylcysteine

Oral form

IV form now approved

Prevents the formation of hepatotoxicmetabolites



Anti-inflammatory

Agents



Nonsteroidal Anti-inflammatoryDrugs

Group of frequently prescribed drugs

Treat pain

Common drug Acetylsalicylic acid (ASA)

Hermann Kolbe



Uses for NSAIDs

Analgesic (mild to moderate)

Antigout

Anti-inflammatory

Antipyretic

Relief of vascular headaches

Platelet inhibition



How NSAIDs Work

Stop the activation of the arachidonicacid pathway

Reduce:

Pain Headache

Fever

Inflammation



Analgesics

Reduce pain by blocking prostaglandins



Antipyretics

Inhibit prostaglandin E2 in the brain



Inflammation Relief

Inhibit either the:

Leukotriene pathway

Prostaglandin pathway

Or both pathways



Pain Relief

Relief of mild to moderate pain Bone, joint, and muscle pain

Osteoarthritis

Rheumatoid arthritis Juvenile rheumatoid arthritis

Dysmenorrhea



Common NSAIDs

Common drugs that are used: Ibuprofen (Motrin, Advil)

Ketoprofen (Orudis)

Ketorolac (Toradol) Naproxen (Naprosyn)



Gastrointestinal Side Effects

First-generation NSAIDs

Dyspepsia, heartburn, epigastric distress,nausea

Gastrointestinal bleeding Mucosal lesions (erosions or ulcerations)

(continues)

(continued)



Gastrointestinal Side Effects

Second-generation NSAIDs

Called COX-2 inhibitors More specific in their action

Reduce gastrointestinal distress

(continued)



Cardiovascular Side Effects

Second-generation NSAIDs Serious side effects:

Cardiac arrhythmias

Heart attack Stroke

Celecoxib (Celebrex) may be removed

Rofecoxib (Vioxx) removed from market by

the FDA



Precautions

First and second generation Do not take if you:

Have or had stomach ulcers and bleeding

Have had asthma

Have had an allergic response to aspirin or sulfa

Have severe kidney problems

Have severe liver problems

Are pregnant



Renal Side Effects

Creatinine clearance reduced

Renal failure Acute tubular necrosis



Nursing Assessment

Before beginning therapy, performthorough assessment for:

Gastrointestinal lesions or peptic ulcer

disease Bleeding disorders

Heart disorders

Perform lab studies CBC, platelet count, cardiac, renal, and liver



Medical History

Medication history

Serious drug interactions Alcohol

Heparin and warfarin (Coumadin) Phenytoin

Steroids

Sulfonamides



Salicylates

Do not give Salicylates to children under age 12.

Reye’s syndrome

- Ralph Douglas Reye

- rare childhood disease: a rare and seriouschildhood disease, usually following arespiratory infection, causing vomiting, fattydeposits in the liver, disorientation, andswelling of the kidneys and brain

Give with food and milk.



Client Education

Educate clients about precautions. Watch for:

Unusual bleeding, abdominal pain, andcardiac problems

Enteric-coated tablets should not becrushed or chewed.



Therapeutic Effects

Monitor for: Decrease in swelling

Decrease in pain

Decrease in joint tenderness

lesson 4 analgesics

Documents