Chronic Pain & Drug Therapy – Pharmacology

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Chronic Pain & Drug Therapy – Pharmacology

This quiz is about chronic pain and drug therapy of pharmacology.

Visceral Pain

Arises from internal organs
Deep aching or sharp stabbing pain

Neuropathic Pain

-Arises from injury to nerves
–Burning, shooting, stabbing
-Abnormal pain processing
–Makes difficult to treat

Types of Pain

–Caner Chronic Pain
–Chronic Non-Cancer Pain

Acute Pain

-Short duration (< 3-6 months)
-Identifiable cause
-Acute pain ↓ as healing occurs
-Severity of pain equals acuity of the injury or disease process
-Specific & localized in nature
-Drugs usually work
-Sympathetic nervous system response
–Fight or Flight Response
–hypertension, tachycardia, restlessness, anxiety, diaphoresis/pallor, urinary retention, anxiety/agitation/confusion

Chronic Pain

Caner Chronic Pain
Chronic Non-Cancer Pain
-Pain lasts > than 3-6 months.
-Sometimes identifiable cause
-Pain severity > stage of the injury or disease
-Often periods of waxing and waning
-Requires more and more drug therapy
-Persists beyond healing stage
-NO sympathetic nervous system responses.
-Depression, irritability, flat affect, fatigue, decrease physical activity, withdrawal

Characteristics of Pain

-Mild to severe
-Sympathetic NS response
-Related to tissue injury
-Restless and anxious
-Reports pain
-Behavior indicative of pain


-Mild to severe
-Parasympathetic NS response
-Continues beyond healing
-Depressed and withdrawn
-Does not mention pain
unless asked
-Pain behavior often absent

Pain Relief

–Morphine-like substance
–Able to “close the gate”

Gate Control Theory

-Theory about how pain is transmitted and blocked
-Proposes that only one pain pathway (gate) is open at one time. The brain therefore does not perceive pain while it is preoccupied with other sensory input.
-Explains how massage, vibration, heat, and cold reduce pain sensations
Melzack & Wall, (1965)

When should you assess for pain?

-on admission
-pain is the 5th vital
-at all encounter with pt
-be alert for pain
-identify pt at risk
-for pain
Don’t wait to be told

Pain Assessment

Provoking factors
Region or radiation
Severity or intensity

Pain Assessment


Pain Assessment


Why Use a Pain Scale ???

-Quantify data with a number
-Maintain consistency between ratings
-Make the data objective
-Note: Some facilities may make it policy to use one or more particular scales

Non-Verbal Pain Assessment

-Observe the patient for 3-5 minutes
-Behavioral Pain indicators
–Facial Expressions
–Behavior changes

American Geriatric Society Panel On Persistent Pain In Older Persons

Identified 6 common pain indicators
Facial expressions of grimacing, 1.crying
3.Body movements
4.Changes in interpersonal interactions
5.Changes in activity or routines
6.Mental status changes

Psychosocial Aspects of Pain

-Meaning of pain to patient and family
-Past experiences with pain
Effect on:
-all aspects of all life
-daily activities
-family and financial
Spiritual & Cultural


.Many factors influence addiction
.Occurs over time
–Impaired control over drug
–Compulsive use
–Continued use despite harm and craving


– “Addictive Behaviors” because pain is under treated
-Anger/esculating demands for more meds
–Results in suspicion and avoidance by staff
-Common with chronic pain
-Behavior resolved when pain is adequately treated

Tolerance vs. Physical Dependence

Repeated use decreases the effect of drug over time
patient need increasing doses to achieve same pain relief.

Physical dependence

Physical Dependence
Results in physical withdrawal symptoms when drug abruptly discontinued, rapid dose reduction or reversal agent given

Occurs in everyone who takes opioids over long period of time


-Important role of nurse is to assess for and prevent withdrawal
-Symptoms of opioid withdrawal:
-Nausea, vomiting
-Abdominal cramping
-Muscle twitching

Substance Abusers

-Often result of traumatic injury or health problems that cause pain
-Patients with chronic pain medication use should not have medications stopped abruptly
-May require higher doses of conventional drugs
-Should be identified so appropriate therapy can be prescribed

Placebo Therapy

-Only indicated use is in research studies
-Need informed consent
-Is unethical to administer placebos to your patients

Before Administering Pain Medications

The nurse should:
-Assess for drug allergy
-Ask patient’s current medications
-Assess the patient’s current pain status
-Check vital signs

Drug Groups


Pain Treatment

Mild (1-3)
Moderate (4-6)
-Weak opioids
Severe Pain (7-10)
-Strong opioids

Adjuvants: Can be used at every level of pain

Non-Opioid Analgesics

Most Common
-Acetylsalicylic acid (aspirin)
-Acetaminophen (Tylenol)
-Most are NSAIDs, including aspirin:
–Adverse effects: GI disturbances, bleeding
–COX-2 inhibitors for long-term use

Opioid Analgesics

-Used in management of all types of pain
-Work centrally to block release of neurotransmitters in spinal cord
-Bind to MU receptors to block release of substance P which prevents the transmission of pain
-Most opiods are similar in effect
-Response varies widely
-Can be administered in many different routes


-Opioid Agonists: Bind and cause analgesia. By binding to pain receptors they block the transmission of pain to the brain.
–Example: Morphine Sulfate
Opioid antagonists: bind to receptors but do not cause analgesia.
–Example: Naloxone (Narcan). It is used for overdose, oversedation secondaryto opioids.


There is no analgesic dosage ceiling (limit)
Side effects include:
Respiratory depression
Nausea & vomiting
Urinary retention
Postural Hypotension
-Also have antitussive and antidiarrheal properties

Equalanalgesic Dosing

Not all opioids are the same strength
Morphine sulfate is the gold standard
standard against all other opioids are measured

Weak Opioids

Used for moderate pain and are often found in combination medications
Codeine and Tylenol (Tylenol#3)
Hydrocodone and Tylenol (Vicodin, Loratab)
Oxycodone and Tylenol (Percocet,Tylox).

Strong Opioids

Opioids for moderate to severe pain
Morphine Sulfate
Hydromorphone (Dilaudid)
8 times stronger than morphine
Fentanyl (Duragesic)
IV (acute pain, on pump)
Patches, oral (chronic and cancer pain)
Meperidine (Demerol)
Methadone (Dolophine)-chronic pain or drug dependent patients


Synthetic opioid
Toxic metabolite, normeperidine that can cause seizures.
Meperidine half life 2-4 hours
Normeperidine half life 24-48 hours with normal renal function.
Should only be used for a short period of time (2-3 days)

Meperidine Toxicity

-Older adults at high risk
-People with decreased renal clearance
-Assess patients for complaints of numbness, twitching, confusion and seizures

Professional Role of Nurse:
Ensure Comfort and Safety

-Assess for pain
–Monitor BP & Respirations prior to administration
-Believe the patient
-Medicate with appropriate medication
-Assess for adverse effects
-Expected Outcomes: Pain relief and drowsiness

Sedation occurs before respiratory depression

Respiratory Assessment

Monitor rate and depth of respirations
Especially while sleeping
Severe respiratory depression usually seen with IV administration or in patient with no tolerance to opioids

Treatment for Respiratory Depression

1.Attempt to arouse patient
2.Administer opioid antagonist Naloxone (Narcan) IV
-Fast acting
-Reverses opiod effect
-Pain will quickly return

3.Continue to monitor as effects of respiratory depression will outlast the Narcan and respiratory depression can reoccur

Nursing Interventions to Prevent Side Effects of Opiods

-Ongoing assessment for over sedation and respiratory depression
-Assess for constipation
–Push fluids & encourage ambulation
–Administer stool softeners & laxatives as ordered
-Nausea & vomiting
Administer antiemetics as prescribed

Routes of Administration

-Preferred route for pain control
–Especially chronic
-Expect onset in 30 minutes
-Long acting and controlled release available
–May not be crushed

Routes of Administration

Variable absorption rates
Tissue fibrosis and abscess can form after repeated injections
Onset 30-45 minutes
Not recommended for pain control
Onset within minutes
Most efficient

Routes of Administration

Fentanyl (Duragesic)
Long duration of action (48-72 hours)

Rectal Suppository

Absorbed through the rectal mucosa
Many opioids can be administered via this route
Slower onset of action

Sublingual/ Buccal

Sublingual-placed under tongue
Buccal: Fentanyl (Actiq) oral transmucosal system


Butorphanol (Stadol) agonist-antagonist
Sumtatriptan for migraines
Good for out-patient use


PCA (Patient Controlled Analgesia)
Patient controls delivery of medication
Dosage preset
Use less drug
Fewer side effects
Less time for nurse
Vital Signs, pain level,side effects monitored closely

Patient Controlled Analgesia

Settings: continuous, PCA or continuous with PCA
Example of an order:
Morphine Sulfate
Loading dose 2 mg
0.5mg continuous
PCA dose 1mg
Lockout 6 minutes
4 hour limit: 20mg

Benefits and Risks

Empowers patients
Better control of pain
Reduces patient anxiety
Over sedation and respiratory depression
Drug administration set-up errors
Others besides patients pushing the button

Nursing Responsibilities

Monitor for adverse effects & follow protocols
VS & sedation levels every 2 hours
Assess for other side effects:
-Urinary retention
Educate patients on proper use and what to report
Obtain other pain therapies for patients who cannot administer PCA competently

Adjuvant drugs

Not true analgesics
Work alone or in combination to relieve pain
Enhance or potentate effectiveness of pain relief
Good with chronic pain and complex pain syndromes
Tricyclic antidepressants
Antiseizure medications
Antianxiety drugs

Topical and Local Anesthesia

Topical anesthesia
Local anesthetic infusion pumps: ON-Q Pump

Adjuvant Drugs

-Reduce need for opiods
-Work better for some types of pain
-Treat associated symptoms of depression and sleep disorders with chronic pain

Best Practices for Scheduling of Medication

-Pre-medicate for painful procedures/activities
-Around the clock dosing preferred
–Assess minimum every 4 hours
-Treat pain early for better effect
-Breakthrough dosing for cancer pain
-Follow BRN of CA guidelines

Nonpharmacological Interventions

Cognitive-Behavioral Measures
Alternative Medicine
Complementary Medicine

Cutaneous Stimulation

-Application of heat and cold
-Therapeutic touch

Trancutaneous Electrical Stimulation

Cutaneous electrical stimulation
Usually initiated by PT
Empowers patient and gives some control

Physical Measures

Physical Therapy & Occupational Therapy
Goal to increase function, decrease pain
–Heat and cold therapies


#1 reason to seek medical attention

Cognitive-Behavioral Therapy

–Very effective
–Transient, best used with other measures
-Guided imagery
-Modify environment

Alternative Therapies

-Magnet therapy

Pain Management In The Elderly Patient

-Pain is prevalent in the elderly
-At risk for under treatment
-Don’t describe the pain as “pain” but may call it discomfort, or soreness
-Tend to report less often
-May view as sign of weakness or
something to be lived with
-Don’t want to be a bother

Assessment Guidelines In The Elderly Patient

-Assume pain is present
-Ask about present pain only
-Use a standard scale
-Use a variety of descriptors
ache, sore, hurt
-If cognitively impaired assess for non-verbal symptoms of pain

Management of Pain in the Elderly

Use round the clock dosing
Start low and go slow
Monitor for adverse effects
Drug interactions
Avoid use of meperidine (Demerol)
Use nondrug therapies

Definition of Pain

“Unpleasant sensory and emotional experiences associated with actual and potential tissue damage”
study of pain 1979

Definition of Pain

“Whatever the experiencing person says it is, existing whenever s/he says it does.”
Margo McCaffery (1968)

Nurse As An Advocate

Primary role of the nurse in pain management is believing their patients.

The Joint Commission Pain Standards

-American Pain Society
-“Pain Care Bill of Rights”
.Patients have the right to be taken seriously and treated
.Have pain assessed and promptly treated
.Have ongoing reassessment & evaluation
.Treatment modified if not working
.Referral to pain specialist for persistent pain

Contribute to Ineffective Pain Management

-Too much pain medication too frequently constitutes substance abuse, causes addiction, will result in respiratory depression or will hasten death
-language barrier
-comatos pt

High Risk Population for Under treatment

-Infants and children
-Older Adults
-cognitive dysfunction
-emotional /mental illness
-pt with terminal ill
-cultural difference
-pt who speaks a difference langugue

Untreated Pain

-Physiologic Impact
-Quality-of-Life Impact
-Financial Impact

ABCs of Pain Management

A-Ask, Assess
C-Choose appropriate medication
D-Deliver the medication in a timely, logical, coordinated fashion
E-Empower the patient

Nurses’ Attitudes/Barriers

-Attitudes of health care providers and nurses affect interaction with patients experiencing pain.
-Individual experiences with pain
-Personal use of meds or Nonpharmacological methods to manage pain
-Family’s or SO’s hx or experience with substances for pain control or mood altering effect

Physiology of Pain

Periphery ——>Noxious stimuli

Physiology of Pain


Pain Stimulation

Tissue damage—> release of chemicals——> increase excitability and frequency of nerve impulses


-Release of multiple substances
substance P


Pain Transmission

-To be perceived the pain stimuli must be transmitted first to the spinal cord
-Then signals sent to the central areas of the brain


Slow or Express Train?

A Delta fiber small, myelinated fibers; send impulses quickly producing sharp, pricking, well localized pain of a short duration.

C Fiber smallest, unmyelinated fibers, send impulses slower producing dull, aching, burning sensations with a diffuse, slow onset of a long duration


-Conscious experience of Pain

Involves several brain structures
Reticular activating system: autonomic response (sympathetic nervous system)
Somatosensory system: localization and characterization of the pain
Limbic: emotional and behavior responses
Cortical: meaning of pain

Pain Tolerance

Pain tolerance: The maximum degree of pain intensity that a person is willing to experience.

Ex: Bad day….stub toe….worst pain ever experienced

Factors Affecting Pain

-Women have more:
–pain in women
–Arthritis, fibromyalgia
-Men have more:
–Back pain
-Sociocultural background

Physiologic Sources of Pain

Nociceptive —>normal


Normal processing of pain
2 Types: Somatic and Viceral
-Superficial: Skin and tissues (incisions, drains)
Sharp and burning
-Deep somatic: Bone, muscle, blood vessels (muscle spasms, orthopedic procedures
-Dull, aching, cramping