PAIN MANAGEMENT.

INTRODUCTION

Pain is a universal human experience and the most common reason people seek medical

care. Pain tells us something is wrong in the structure or function of our body and that we

need to do something about it. Because pain is such a strong motivator for action, it is

considered one of the body’s most important protective mechanisms.

DEFINITIONS OF PAIN

The International Association for the Study of Pain defined pain as “an

unpleasaGnt, subjective, 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, 1979).

Pain, however, is much more than a physical sensation caused by a single entity. It is

subjective and highly individual, a complex mechanism with physical, emotional, and

cognitive components.

Pain cannot be objectively measured in the same way as, for example, the chemical

content of urine or the oxygen content level of blood. Only the person who is suffering

knows how the experience feels.

McCaffery defined pain as “whatever the experiencing person says it is and

whenever he says it does” (1979).

The American Pain Society goes further by stating that it is “not the responsibility

of clients to prove they are in pain; it is the nurse’s responsibility to accept the

client’s report of pain” (2005).

PAIN-RELATED TERMINOLOGY

Algesia: Sensitivity to pain.

Breakthrough pain: Transitory increase in pain to a level greater than the client’s well-

controlled baseline level (McCaffery & Pasero, 2003).

Hyperalgesia: Excessive sensitivity to pain.

Idiopathic pain: Chronic pain for which there is no identifiable psychological or physical

cause.

Intractable pain: Pain that is not relieved by ordinary medical, surgical, and nursing

measures (Mosby’s Dictionary, 2009).

Pain threshold: Amount of pain required before individuals feel the pain. The lower the

threshold, the less pain they can endure; the higher the threshold, the more pain they can

endure.

Pain tolerance: Maximum amount and duration of pain a person can endure. Tolerance

varies widely among people and is influenced by emotions and cultural background.

Pain syndrome: A group of symptoms of which pain is the critical element, such as

headaches and post-herpetic neuralgia.

Phantom limb pain: Pain that occurs in a limb after it is removed or as a result of severe

damage to the affected nerve plexus due to perceptual disruption in the brain.

Psychogenic pain: Chronic pain with no identified organic explanation.

Radiating pain: Pain that begins at one place and extends out into nearby tissues.

Referred pain: Pain that is felt at a different location than where tissue was damaged. This

phenomenon occurs because pain fibers in the damaged area synapse near fibers from other

areas of the body; for example, a myocardial infarction may create referred pain in the left

shoulder.

PHYSIOLOGY OF PAIN

The following is a brief review of the four basic concepts that are important to begin to understand the physiology of pain. The concepts are transduction, transmission, modulation, and perception.

Transduction is the process by which afferent nerve endings participate in translating noxious stimuli (e.g., a pinprick) into nociceptive impulses.

Noxious stimulation is first carried by the faster A-delta fibers, and then by the slower C fibers. “Silent nociceptors,””, also involved in transduction, are afferent nerves that do not respond to external stimulation unless inflammatory mediators are present. The peripheral nervous system

contains primary sensory afferent neurons that have an important role in pain signaling. The axons of these afferents diverge from the cell body in the dorsal root ganglion near the spinal cord and send a short fiber centrally into the cord and a long fiber down the peripheral nerve into the tissues. Their receptors detect mechanical, thermal, proprioceptive, and chemical stimuli.

Transmission is the process by which impulses are sent to the dorsal horn of the spinal cord, and then along the sensory tracts to the brain.

The primary afferent neurons are active senders and receivers of chemical and electrical signals. Their axons terminate in the dorsal horn of the spinal cord, where they have connections with many spinal neurons. In turn, spinal neurons have input from many primary afferents. These spinal neurons project axons to the contralateral thalamus, which in turn projects to the somatosensory pathway, frontal cortex, and other areas. The somatosensory cortex is thought to be involved in the sensory aspects of pain, such as the intensity and quality of pain, whereas the frontal cortex and limbic system are thought to be involved with the emotional responses to it.

Modulation is the process of dampening or amplifying these pain-related neural signals. Modulation takes place primarily in the dorsal horn of the spinal cord, but also elsewhere, with input from ascending and descending pathways.

The gate control theory is a popular model of pain modulation proposed by Melzack and Wall in 1965, later revised by Melzack and Casey in 1968. These investigators proposed the existence of an endogenous ability to reduce or increase the degree of perceived pain through modulation of incoming impulses at a gate located in the dorsal horn of the spinal cord. The gate acts on signals from the ascending and descending systems and weighs all of the inputs. The integration of these inputs from sensory neurons, the segmental spinal cord level, and the brain, determines whether the gate will be opened or closed, either increasing or decreasing the intensity of the ascending pain signal.   The role of psychological variables in the perception of pain, including motivation to escape pain, and the role of thoughts, emotions, and stress reactions in increasing or decreasing painful sensations, is evident in the gate control theory. An example is when patients report more pain at night, when they are isolated and less distracted from their pain than they might be during the day. The proposed gate can be opened or closed by pharmacologic manipulation

GATE-CONTROL THEORY

Melzack and Wall proposed the gate-control theory to explain the relationship between

pain and the emotions (1982). According to the theory, a gating mechanism occurs when

a pain impulse travels to the substantia gelatinosa in the dorsal horn of the spinal cord.

There, trigger (T) cells influence the transmission of pain impulses. When their activity is

inhibited, the gate closes and impulses are less likely to be transmitted to the brain. This

mechanism is controlled by descending nerve fibers from the thalamus and cerebral

cortex, areas of the brain that regulate thought and emotions. The gate-control theory

helps explain how thoughts and emotions modify the perception of pain and why

interventions, such as imagery and distraction, help relieve it.

n, transduction, transmission and modulation, and psychological intervention.

Perception refers to the subjective experience of pain that results from the interaction of transduction, transmission, modulation, and the psychological aspects of the individual.

As research continues furthering the understanding of this complex process, there is hope that pain treatments can be developed to target specific parts of the physiologic pathway and become more effective than current treatmen

Neurologic transmission of pain stimuli. (Illustration by Jason McAlexander. © 2005,

Wild Iris Medical Education, Inc.)

Factors That Influence Pain

The perception of pain is influenced by physiologic, psychological, and cultural factors,

all of which caregivers need to consider.

PHYSIOLOGICAL FACTORS

Age

Age affects the way people respond to pain. It influences both the development and decline of

the nervous system.. The following table gives a brief overview of the perception of pain relative

to age.

AGE AND THE PERCEPTION OF PAIN

Age Pain Perception

Pre-term infants Have anatomical and functional ability to process pain by mid to late gestation; seem to have greater sensitivity to pain than term infants or children

Newborn infants Response to pain is inborn and does not require prior learning; respond to pain with behaviors such as crying, grimacing, moving body

Infants, 1 month Can metabolize analgesics and anesthesia effectively; can recognize caregiver as comforter

Toddlers/Preschoolers Can describe pain, its location and intensity; respond to pain by crying, anger, sadness; may consider pain a punishment; may hold someone accountable for pain and remember experiences in a certain location, such as a clinic

School-age children May try to be brave when facing a painful procedure; may regress to an earlier stage of development; seek understanding of reasons for pain

Adolescents May be slow to acknowledge pain; may consider showing signs of pain a weakness; may regress to earlier stages of development with persistent pain

Adults Fear of pain may prevent some from seeking care; may believe admission of pain is a weakness and inappropriate for age or sex; may consider pain a punishment for moral failure

Older adults May have decreased sensations or perceptions of pain; may consider pain an inevitable part of aging; chronic pain may produce anorexia, lethargy, depression; may not report pain due to fear of expense, possible treatment, dependency; often describe

AGE AND THE PERCEPTION OF PAIN

Age Pain Perception

pain in nonmedical terms such as “hurt” or “ache”; may fear addiction to analgesics; may not want to bother nurses or be a “bad patient”

Fatigue

Fatigue decreases coping abilities and heightens the perception of pain. When people are

exhausted from physical activity, stress, and lack of sleep, their perception of pain may

be heightened and their coping skills diminished. Thus, sleep and rest from physical,

emotional, and social demands are important measures to manage pain more effectively.

Genetic Makeup

Recent research suggests that sensitivity to and tolerance for pain may a genetically

linked trait (Ruda et al., 2000). This finding does not negate the need to manage pain

adequately, regardless of inherited traits.

Memory

Memory of painful experiences, especially experiences that occurred as a very young

child, may increase sensitivity and decrease tolerance to pain. For example, even young

children remember the pain of an immunization at the doctor’s office and henceforth may

be afraid to visit the doctor again.

Stress Response

Research has shown that “severe, unrelieved pain can cause an overwhelming stress

response in both pre-term and full-term infants which can lead to serious complications

and even death” (Pasero, 2004). In recent years, post-traumatic stress syndrome has been

the subject of extensive research, both as to its cause and its treatment (Hamilton, 2008).

Healing

Recent research suggests that unrelieved acute pain slows postoperative wound healing

(McGuire, 2006). This evidence is not surprising, given our increasing knowledge of the

effect of stress on the human body.

Neurologic Function

Any factor that interrupts or interferes with normal pain transmission affects the

awareness and response of clients to pain and places them at risk for injury. Analgesics,

sedatives, and alcohol depress the functioning of the central nervous system. Some

diseases, such as leprosy, damage peripheral nerves, decrease sensitivity to touch and

pain, and render sufferers more vulnerable to injury.

PSYCHOLOGICAL FACTORS

Fear and Anxiety

The relationship between pain and fear is convoluted and complex. Fear tends to increase

the perception of pain, and pain increases feelings of fear and anxiety. This connection

occurs in the brain because painful stimuli activate portions of the limbic system believed

to control emotional reactions.

Coping

People manage pain and other stressors of life in different ways. Some see themselves as

self-sufficient, internally controlled, and independent. As a result, they may deny pain or

be slow to admit they are suffering.

CULTURAL FACTORS

Cultural beliefs and values affect the way people respond to pain. As children they learn what is

and what is not acceptable behavior when experiencing pain. In some cultures, any expression of

pain is considered cowardly and shameful. In others, noisy demonstrations of pain are expected

and acceptable. The meaning of pain itself may be markedly different in different cultures. Some

ethnic groups see pain as a punishment for wrongdoing

PAIN CLASSIFICATION

There are two basic types of pain: acute and chronic.

Acute pain occurs for brief periods of time and is associated with temporary disorders. However, it is always an alarm signal that something may be wrong.

Chronic pain is continuous and recurrent. It is associated with chronic diseases and is one of their symptoms. Pain intensity not only depends on the type of stimulus that caused it, but also on the subjective

perception of the pain. Despite a wide range of subjective perception, several types of pain have been classified according to:

The stimulus that caused the pain. The pain's duration.

The features of pain (intensity, location, etc.).

The main types of pain described by this system of classification are:

Gnawing pain. Continuous with constant intensity. It generally worsens with movement. Throbbing pain. This is typical of migraine pain. It is caused by dilation and constriction

of the cerebral blood vessels.

Stabbing pain. Intense and severe. It is caused by mechanical stimuli.

Burning pain. A constant, burning feeling, like, for example, the type of pain caused by heartburn. 

Pressing pain. Caused by constriction of the blood vessels or muscles.

There are also specific types of pain:

Muscle pain. Also known as myalgia, this pain involves the muscles and occurs after excessive exertion or during inflammation.

Colicky pain. Caused by muscle contractions of certain organs, such as the uterus during the menstrual period. Generally cyclic in nature.

Referred pain. Occurs when the painful sensation is felt in a site other than the one where it is actually occurring, depending upon how the brain interprets information it receives from the body.

Postoperative pain. Occurs after surgery and is due to lesions from surgical procedures.

Classification of Pain

Classification of pain: Classifying pain is helpful to guide assessment and treatment. There are many ways to classify pain and classifications may overlap (Table 1). The common types of pain include:

Nociceptive: represents the normal response to noxious insult or injury of tissues such as skin, muscles, visceral organs, joints, tendons, or bones.

o Examples include:

Somatic: musculoskeletal (joint pain, myofascial pain), cutaneous; often

well localized

Visceral: hollow organs and smooth muscle; usually referred

Neuropathic: pain initiated or caused by a primary lesion or disease in the somatosensory nervous system.

o Sensory abnormalities range from deficits perceived as numbness to hypersensitivity (hyperalgesia or allodynia), and to paresthesias such as tingling.

o Examples include, but are not limited to, diabetic neuropathy, postherpetic neuralgia, spinal cord injury pain, phantom limb (post-amputation) pain, and post-stroke central pain.

Inflammatory: a result of activation and sensitization of the nociceptive pain pathway by a variety of mediators released at a site of tissue inflammation.

o The mediators that have been implicated as key players are proinflammatory cytokines such IL-1-alpha, IL-1-beta, IL-6 and TNF-alpha, chemokines, reactive oxygen species, vasoactive amines, lipids, ATP, acid, and other factors released by infiltrating leukocytes, vascular endothelial cells, or tissue resident mast cells

o Examples include appendicitis, rheumatoid arthritis, inflammatory bowel disease, and herpes zoster.

Clinical Implications of classification: Pathological processes never occur in isolation and consequently more than one mechanism may be present and more than one type of pain may be detected in a single patient; for example, it is known that inflammatory mechanisms are involved in neuropathic pain.

There are well-recognized pain disorders that are not easily classifiable. Our understanding of their underlying mechanisms is still rudimentary though specific therapies for those disorders are well known; they include cancer pain, migraine and other primary headaches and wide-spread pain of the fibromyalgia type.

Pain Intensity: Can be broadly categorized as: mild, moderate and severe. It is common to use a numeric scale to rate pain intensity where 0 = no pain and 10 is the worst pain imaginable:

Mild: <4/10

Moderate: 5/10 to 6/10

Severe: >7/10

Time course: Pain duration

Acute pain: pain of less than 3 to 6 months duration

Chronic pain: pain lasting for more than 3-6 months, or persisting beyond the course of an acute disease, or after tissue healing is complete.

Acute-on-chronic pain: acute pain flare superimposed on underlying chronic pain.

Sources of Pain

The sources of pain are divided into three main categories: nociceptor, non-nociceptor,

and psychogenic.

Nociceptor pain results when tissue damage produces a pain-producing stimulus

that sends an electrical impulse across a pain receptor (nociceptor) by way of a

nerve fiber to the central nervous system. Nociceptor pain is further divided into

visceral and somatic pain.

Visceral pain results from stimulation of nociceptors in the abdominal cavity

and thorax.

Somatic pain is divided into deep somatic and cutaneous pain. Deep somatic

pain arises from bones, tendons, nerves, and blood vessels. Cutaneous pain

originates in the skin or subcutaneous tissue. Some body tissues, such as the

brain and lung, have no nociceptors, and some tissues have many.

Non-nociceptor (neuropathic) pain is caused by direct injury to structures of the

nervous system.

Psychogenic pain is pain for which there is little or no physical evidence of organic

disease or identified injury to tissues in the body. Lack of evidence, however, does not

mean clients are malingering or that they are not suffering.

PHYSIOLOGIC SOURCES OF PAIN

Source: Adapted with permission from Ignatavicius et al., 1999.

Nociceptor: Visceral

Physiologic structures Organs and linings of body cavities

Mechanism Activation of nociceptors

Characteristics Poorly localized, diffuse, deep, cramping or splitting

Sources of acute pain Chest tubes, abdominal drains, bladder and intestinal distention

Sources of chronic pain syndromes

Pancreatitis, liver metastases, colitis

Nociceptor: Somatic

Physiologic structures Cutaneous: skin and sub-cutaneous tissues Deep somatic: blood, muscle, blood vessels, connective tissue

Mechanism Activation of nociceptors

Characteristics Well-localized, constant and achy

Sources of acute pain Incisional pain, insertion sites of tubes and drains, wound complications, orthopedic procedures, skeletal muscle spasms

Sources of chronic pain syndromes

Bony metastases, osteoarthritis, rheumatoid arthritis, low-back pain, peripheral vascular disease

Non-nociceptor (neuropathic)

Physiologic structures Nerve fibers, spinal cord, and central nervous system

Mechanism Non-nociceptive injury to nervous system structures

Characteristics Generalized along distribution of damaged nervous structures

Sources of acute pain Poorly localized: shooting, burning, fiery, shock-like, sharp, painful numbness

Sources of chronic pain syndromes

Nervous tissue injury due to diabetes, HIV, chemotherapy, neuropathies, postherpetic neuralgia, trauma, surgery

Psychogenic

Physiologic structures No organic structures

Mechanism Emotional

Characteristics Variable, often numerous

Sources of acute pain Nonorganic

Sources of chronic pain syndromes

Nonorganic psychological factors

.

PAIN AND THE NURSING PROCESS

The nursing process includes assessment, diagnosis, planning, intervention, and

evaluation. To manage pain responsibly, nurses use each step of the nursing process.

Basic to every strategy for managing pain is showing respect for the validity of a client’s

experience of pain. To communicate respect, nurses:

Acknowledge pain and take action to manage it.

Give accurate information to reduce anxiety and facilitate relief of pain.

Reduce environmental stressors that add to the experience of pain.

Encourage disclosure of feelings and fears.

Provide privacy and maintain confidentiality.

Assessing Pain

Pain is a red flag. It tells us there is a problem somewhere in the body that is crying out

for attention. In fact, pain is such an important indicator of health, its assessment has been

called the “fifth vital sign,” joining temperature, pulse, respiration, and blood pressure.

Even so, until we know more about a specific pain, we cannot fix it. To do this, nurses

must gather information from as many sources as possible, especially the primary source,

the person in pain. This investigation includes obtaining a comprehensive pain history,

making observations of behaviors, performing an appropriate physical examination, and

consulting with other healthcare professionals.

PAIN HISTORY

A pain history is obtained from written documents and from interviews with the person in

pain, family members, and other caregivers. It asks specific questions about the location,

intensity, quality, and history of the pain, as shown in the following box. In some

facilities these questions are printed on an assessment form, with space for answers to be

recorded beside each question.

OBTAINING A PAIN HISTORY

Location: Where is your pain? Ask client to point to the area of pain.

Intensity: On a scale of 0 to 10, with 0 representing no pain, how much pain would you say

you are experiencing? If your pain were a temperature, how cold or hot would it be (warm,

hot, blistering)? If your pain were a sound, how loud would it be (silent, quiet, strident,

booming)?

Quality: In your own words, tell me what your pain feels like (worms under the skin,

shooting, needle pricking, tingling, etc.).

Chronology/pattern: When did the pain start? Does your pain come and go? How often?

How long does it last?

Precipitating factors: What triggers the pain, or what makes it worse?

Alleviating factors: What measures have you found that lessen or relieve the pain? What

pain medications do you use? How much and how often?

Associated symptoms: Do you have other symptoms before, during, or after your pain

begins (dizziness, blurred vision, nausea, and shortness of breath)?

BEHAVIORAL OBSERVATIONS

Most people who suffer pain usually show it either by verbal complaint or nonverbal behaviors.

The following table lists some typical behaviors nurses may observe when they assess people in

pain.

NONVERBAL BEHAVIORS INDICATING PAIN

Facial Expressions Vocalizations Body Movement Social Interaction

Clenched

teeth

Wrinkled

forehead

Biting lips

Scowling

Crying

Moanin

g

Gaspin

g

Groani

Restlessness

Protective

body movement

Muscle tension

Immobility

Silence

Withdrawal

Reduced

attention span

Focus on pain

relief measures

NONVERBAL BEHAVIORS INDICATING PAIN

Facial Expressions Vocalizations Body Movement Social Interaction

Closing eyes

tightly

Widely

opened eyes or

mouth

ng

Gruntin

g

Pacing

Rhythmic

movement

PHYSICAL EXAMINATION

When clients complain of pain or show it by their behavior, nurses need to take action to

find the cause. Assessment is most effective if the pain history interview and behavioral

observations are conducted at the same time as the physical examination. For example, if

a client complains of acute pain on the sole of a foot, the nurse visually examines the foot

for unusual signs, observes the person for behavioral cues of pain, and asks about the

onset, intensity, quality, and pattern of the pain and what makes it worse or better. If the

cause is not identified immediately, the nurse refers the client for further assessment.

Diagnosing Pain

An accurate diagnosis depends on an appropriate assessment that focuses on the exact

nature of the pain. The more specific the diagnosis, the more effective interventions can

be. The North American Nursing Diagnosis Association (NANDA) has identified two

primary diagnoses for pain: acute andchronic.

A complete nursing diagnosis, however, goes further. After identifying whether the pain

is acute or chronic, it adds “related to” the medical diagnosis. For example, “chronic pain

related to osteoarthritis of the left hip.” Then, it adds “manifested by” and lists the

various symptoms experienced by the client or signs confirmed by objective data. Thus, a

complete diagnosis might be “chronic pain, related to osteoarthritis, manifested by

stabbing pain in the left hip with weight-bearing.”

The advantage of clear, specific information is that it leads to more effective

interventions. In this case, an appropriate intervention might be an assistive devise such

as a cane or walker and referral to an orthopedic surgeon for further evaluation.

Planning and Goal Setting

During the planning stage, nurses synthesize information from many sources and,

together with the physician, plan appropriate interventions. The goal of these

interventions is to relieve pain and facilitate the highest possible level of functioning.

Practically speaking, this means identifying what activity the pain is preventing and the

best way to achieve a return of function. For the client described above with chronic hip

pain, the activity the pain is preventing is mobility.

Planning interventions means working in partnership with clients and physicians to

provide specific measures to manage the pain. These interventions may be independent or

collaborative. Independent nursing actions fall within the scope of nursing practice and

include controlling the environment, giving emotional support, and providing comfort.

Collaborative nursing actions involve cooperative interventions with other members of

the healthcare team, such as physical therapists, pharmacists, and physicians.

Goal setting involves the identification of attainable objectives and reasonable priorities.

Because every person is different, the nurse discusses various alternatives with the client,

and together they set priorities. For example, after consulting an orthopedic surgeon, the

person with osteoarthritis may decide to delay hip replacement surgery and maintain

mobility as long as possible with the aid of a cane and analgesics for pain.

Interventions

PAIN MANAGEMENT

PHARMACOLOGIC INTERVENTIONS

There are two primary groups of pain medications: nonopioids and opioids. A third group

of drugs called adjuvants or co-analgesics address symptoms that often accompany pain,

such as insomnia, anxiety, muscle spasm, anorexia, and depression.

Nonopioid Analgesics

Nonopioid analgesics relieve pain by acting on peripheral nerve endings at the injury site

to decrease the level of inflammatory mediators. This group of analgesics includes drugs

such as acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs)

such as acetylsalicylic acid (aspirin) and ibuprofen (Motrin). The specific actions and

dosages of these analgesics vary. Generally speaking, however, they have analgesic,

antipyretic, and anti-inflammatory effects and are useful for mild to moderate pain.

With the exception of acetaminophen, most nonopioids are potent anti-inflammatory

agents. These drugs are especially effective when the primary cause of pain is

inflammation, as occurs in rheumatoid arthritis and bone cancer. When tissue is damaged,

a series of biochemical events leads to the release of prostaglandin, which causes edema,

inflammation, and pain.

Two isoenzymes—cyclo-oxygenase-1 (COX-1) and cyclo-oxygenase-2 (COX-2)—play an

important part in this biochemical process. Drugs that inhibit their action, especially that of COX-

2, reduce prostaglandin production and the inflammation it creates. However, these drugs must

be used with caution because the safety of long-term use has not been verified. The following

table lists some common nonopioid analgesics.

COMMON NONOPIOID ANALGESICS

Drug Adult Dose Considerations

Acetaminophen (Tylenol)

650–975 mg q 4 hr Used for headaches, osteoarthritis; lacks peripheral anti-inflammatory activity of NSAIDs

Aspirin 650–975 mg q 4 hr Used for headaches, osteoarthritis, general pain; antipyretic; inhibits platelet aggregation, causing bleeding

Ibuprofen (Motrin) 400 mg q 4–6 hr Used for osteoarthritis; antipyretic; multiple brand names; available as liquid

Indomethacin (Indocin)

150–200 mg/day Used for gout; anti-inflammatory; anti-rheumatic

Naproxen (Naprosyn)

500 mg initial dose, then 250 mg q 6–8 hr

Used for gout, headaches; anti-inflammatory; anti-rheumatic; available in liquid preparation

Opioid Analgesics

Opioid (narcotic, CNS-acting) analgesics are derivatives of opium and include

such drugs as morphine, codeine, and methadone. These drugs modify the

perception of pain and provide a sense of euphoria by binding to specific opiate

receptors throughout the central nervous system. Opiate receptors have various

names, typically denoted by Greek letters such as mu (μ), kappa (κ), and sigma

(σ). Many of the characteristics of particular opioids relate to the receptor to

which they bind. For example, morphine binds to μ receptors and follow μ

receptor control.

Opioid analgesics are classified as full agonists, partial agonists, and mixed agonist-

antagonists.

o Full agonists bind to μ receptor sites, block pain impulses, and produce maximum

pain control—an “agonist effect.” Full agonists include such drugs as morphine

(Kadian, Avinza, Rylomine intranasal), meperidine (Demerol), fentanyl

(Duragesic patch, Fentanyl oralets), oxycodone hydrochloride (OxyContin), and

hydromorphine (Dilaudid).

o Partial agonists produce a lesser response than full agonists and include such

drugs as buprenorphine (Buprenex) and nalbuphine (Nubain

o Mixed agonist-antagonist analgesics include such drugs as pentazocine

hydrochloride (Talwin) and butorphanol tartrate (Stadol). An antagonist is a drug

that competes with opioid receptor sites. Naloxone hydrochloride (Narcan) is

such a drug. It is used for opioid overdoses and physical dependency.

.

OPIOID ADVERSE EFFECTS AND PREVENTIVE MEASURES

Body System Adverse Side Effects Preventative Measures

Cardiovascular Hypotension, palpitations, flushing

Monitor blood pressure and heart rate

CNS Sedation, disorientation, euphoria, dysphoria, light-headedness, lower seizure threshold, tremors

Inform client that tolerance may develop over 3–5 days; administer stimulants as needed

Gastrointestinal Constipation, nausea, vomiting Offer anti-emetic; change analgesic; increase fluid and fiber intake; increase exercise; administer laxatives

Genitourinary Urinary retention Catheterize as needed; administer opioid antagonist

Integumentary Itching, rash, wheal formation Apply cool packs or lotion; administer antihistamine

Respiratory Respiratory depression; aggravation of asthma

Monitor respirations closely; administer opioid antagonist such as naloxone hydrochloride (Narcan)

Some medications combine nonopioid with opioid analgesics in one tablet to offer two

different levels of pain relief—acting both on peripheral nerve endings at the injury site

and at the level of the central nervous system. Acetaminophen with codeine is such a

medication.

Adjuvant Analgesics

Adjuvant analgesics (co-analgesics) are drugs that were developed for uses other than pain but

have been found to enhance the effects of analgesics. Caregivers need to remember that these

are “helper drugs,” not substitutes for analgesics. Clients in pain still need analgesics. The

following table describes some common adjuvant analgesics.

COMMON ADJUVANT (CO-ANALGESIC) DRUGS

Class of Adjuvant Drugs Indications and Primary Effects

Antidepressants: Tricyclics and serotonin, reuptake inhibitors

Burning, neuropathic pain; improves sleep, enhances mood and analgesic effects

Anti-epileptic drugs Neuralgic and neuropathic pain (sharp, prickling, shooting pain)

Antispasmodic Reflex sympathetic dystrophy syndrome

Anxiolytic drugs: Benzodiazepines, buspirone, venlafaxine

Anxiety and sedation

Botulinum toxin Migraine headache

Lidocaine Neuralgic pain and diabetic neuropathic pain

Psychostimulants Offsets sedating side effects and enhances analgesic effects of opioids

Steroids Inflammatory and chronic pain of cancer, malignant spinal cord compression, headaches, and arthritis

Cannabis (Marijuana)

Cannabis is a psychoactive herb derived from the flowers of hemp plants. Although many

people associate it with the treatment of pain, it is not currently accepted for any use by

the U.S. Drug Enforcement Administration, which lists it as a Schedule 1 drug of the

Controlled Substance Act of 1970. Even so, it is marketed as dronabinol (Marinol) and

used in the treatment of glaucoma and intractable nausea. All parts of the plant contain

various psychoactive substances, including tetrahydrocannabinol (THC), the chemical

believed to cause typical psychic effects such as alterations of mood, memory, motor

coordination, cognitive ability, and self-perception. Many states have established medical

marijuana programs to regulate the growth, sale, and use of cannabis.

Placebos

A placebo is a “sugar pill,” an inactive substance prescribed as if it were an effective dose

of a medication. Research has found that placebos produce hoped-for results in 30% to

50% of the people who take them (Thompson, 2000). This so-called “placebo effect” has

been exploited for centuries by hucksters and charlatans who sell tonics, treatments, and

gadgets to people in pain. Because their purpose is to deceive and strip clients of the right

to make informed decisions, legitimate medical practice does not use placebos. Such

acts violate the ethical principles of honesty and autonomy. The only exception to this

prohibition is when subjects give prior consent for the possible use of placebos in

research studies.

World Health Organization Pain Management Ladder

Because of widespread misconceptions about treatment of chronic pain and addiction, in

1990 the World Health Organization (WHO) recommended a three-step pain

management ladder based on the intensity of pain.

1. Mild pain (intensity 1–3 on the 0–10 standard): Use nonsteroidal anti-

inflammatory drugs and adjuvants. If pain persists, then

2. Mild to moderate pain (intensity 4–6): Use combination medications such as

oxycodone and acetaminophen and adjuvants. If pain persists, then

3. Moderate to severe pain (intensity 7–10): Use potent opioids such as morphine,

fentanylm methadone, and adjuvants.

To prevent under-treatment of malignant cancer pain, some authorities recommend a

different approach. They begin the treatment of malignant cancer pain with strong

opioids, providing immediate relief, then slowly reduce the type and dosage until pain

relief is achieved at the lower level (Jackson & Stanford, 2003).

Routes of Administration

Analgesics can be administered by many routes. Each has advantages and disadvantages as well

as indications and contraindications. The overriding considerations are effectiveness and safety.

The table below lists some of the most common routes for the administration of analgesic

drugs.

ANALGESIC DRUG ADMINISTRATION

Route Indications Contraindications

Oral (per os = PO) Preferred route due to lower cost and convenience; may be prepared as powders, capsules, tablets, liquids, or lozenges

Gastrointestinal irritation; inability to swallow; need for more potent analgesic

Rectal (R) Inability to take oral drugs; can be self-administered; longer duration than oral

Anal or rectal lesions, diarrhea, thrombocytopenia

Intramuscular (IM) Acute, short-term pain relief

Need for prolonged pain relief; absorption may be poor; possible muscle or nerve damage; costly

Intravenous (IV) bolus Offers most rapid pain relief (5–15 min) but lasts less than 60 min

Requires IV access; gives only brief pain relief when prolonged relief is needed

Continuous intravenous (IV) infusion

Gives constant opioid blood level when other methods are ineffective

Requires infusion pumps with alarms and close monitoring

Patient-controlled analgesia (PCA)

Allows predetermined IV bolus of analgesic when client desires pain relief

Requires IV access, client cooperation, close supervision; does not give continuous pain relief

Subcutaneous (SC) opioid infusion

Continuous, prolonged parenteral opioids when IV not possible; allows home use

Requires site change every 7 days of 27-gauge butterfly needle; potential site irritation

Intraspinal (neuraxial), intrathecal, epidural, subarachnoid, intraventricular

Labor contractions; also intractable pain when client cannot tolerate systemic opioids by other routes

Requires expert insertion of catheter into intended space; attached to infusion pump or implanted reservoir; high risk for infection or dislodgment

Regional nerve blocks Continuous or single dose analgesic for acute and chronic pain; used for trauma, burns, and labor

Requires expert insertion of catheter to specific nerve root; attached to infusion pump or implanted reservoir; high risk for infection or dislodgment

Topical (cream-laden anesthetic)

Analgesic for needle sticks, venipuncture, dermatitis,

Must be applied 30–60 min in advance of need

ANALGESIC DRUG ADMINISTRATION

Route Indications Contraindications

and insect stings

Transdermal skin patch

Continuous dose of opioid; allows home use

Costly; when body temperature is over 102°F, absorption is accelerated

Nasal sprays Alternative to IV, IM, and oral opioid administration; rapid onset of action

Nasal exudates or mucosal swelling may prevent consistent absorption

Principles for the Use of Analgesics

To guide caregivers, the American Pain Society (2005) identifies thirteen principles

regarding the use of analgesics to control pain:

1. Individualize the route, dosage, and schedule of analgesics medications.

2. Administer analgesics on a regular basis if pain is present most of the day.

3. Know the dose and time course of several opioid analgesic preparations:

Ask client about prior experience with certain drugs.

Give preference to long-acting, sustained-release opioids such as

OxyContin, which provides up to 12 hours of analgesia; Kadian and

Avinza, controlled-release morphine preparations which provide up to 24

hours of pain relief; and transdermal fentanyl, which provides up to 3 days

of pain relief.

Avoid the adverse effects of emesis by giving anti-emetics.

Rotate opioids to compensate for tolerance.

Use rapid-onset opioids when necessary.

Use concentrated dosage forms when injection volume must be minimized.

4. Give infants and children adequate opioid doses. 

5. Follow clients closely, particularly when beginning or changing analgesics.

6. When changing to a new opioid or a different route, first use equianalgesic doses

to estimate the new dose. Then, modify the estimate, based on the clinical

situation and the specific drug.

7. Recognize and treat side effects, such as sedation, constipation, nausea, itching,

respiratory depression, by doing the following:

Change the dose or route of the same drug to maintain constant blood

levels.

Try different opioids analgesics.

Consider multi-drug and multi-modal therapy.

Add another drug that counteracts the adverse effects, such as a stimulant

for sedation.

Use an administration route that minimizes drug concentrations at the site

producing the side effect, such as intraspinal instead of oral when

appropriate.

8. Do not use meperidine (Demerol) because of neurotoxicity risk or mixed agonist-

antagonists (Talwin) because of psychotomimetic effects.

9. Do not use placebos to assess the nature of pain..

NONPHARMACOLOGIC INTERVENTIONS

Although there are myriad drugs to relieve pain, all have some risk and cost. Fortunately,

there are many nonpharmacologic interventions to reduce pain, especially when used in

conjunction with pharmacologic measures. Described as physical and cognitive-

behavioral interventions, many of these approaches are noninvasive, low-risk,

inexpensive, easily performed and taught, and within the scope of nursing practice.

Physical interventions give comfort, increase mobility, and alter physiologic responses.

Cognitive-behavioral interventions alter the perception of pain, reduce fear, give a greater

sense of control, and are considered holistic nursing practice.

Physical Interventions

Comfort measures such as clean and smooth sheets, soft and supportive pillows,

warm blankets, and a soothing environment have been used by nurses throughout

history to relieve pain and suffering. These measures may be difficult to provide

in the noisy, mechanized healthcare facilities of today. Nonetheless, they are

important to the mental and physical well-being of patients.

Position change and movement are well-known pain-relieving interventions.

Moving the body, even a small amount, relieves muscle spasm and provides a

degree of pain relief. So important is movement of the body to health, an entire

profession has developed specializing in physical therapy. However, nurses need

not wait for a specialist to offer these important pain-relieving interventions.

Massage relieves muscle spasm, improves circulation, and provides cutaneous

stimulation. While there are many different massage techniques, they all involve

rubbing the skin in various patterns and degrees of pressure. Once considered an

expected part of basic nursing care, backrubs offer an important noninvasive way

to relieve pain and provide comfort.

Applications of hot and cold are effective pain-relieving measures when used

appropriately. Heat decreases muscle spasm and increases blood flow to an area.

Cold decreases blood flow, edema, and inflammation and may decrease muscle

spasm and pain. Many devices are available to provide hot and cold, including

electric heating pads, patches, and ice packs. Soaks and baths relieve muscle

spasm and are an important means of providing comfort.

Transcutaneous electrical nerve stimulation (TENS) provides a continuous,

mild electric current via 2 to 4 electrodes placed on the skin near a painful site.

The stimulator is a small, battery-operated devise worn by the client. Experienced

as a tingling sensation, TENS works by stimulating large nerve fibers to close the

“gate” in the spinal cord. It also may stimulate endorphin production. TENS may

be used for acute postoperative pain or for chronic conditions such as low back

pain, phantom limb pain, and neuralgia.

Surgical interventions may be recommended when severe pain persists despite

medical treatment. Rhizotomy and cordotomy are two such procedures.

In a rhizotomy the surgeon destroys dorsal posterior nerve roots as they enter the

spinal cord, either by delivering neurolytic chemicals, heat, or extreme cold by way of a

catheter or by performing a laminectomy, isolating the nerve roots, and directly

destroying the nerve

. A chordotomyis more extensive than a rhizotomy, involving resection of the

spinothalamic tract. Both procedures cause permanent loss of pain and thermal

sensations, however they may also cause paralysis due to motor nerve damage.

Cognitive-Behavioral Interventions

Relaxation exercises are useful ways to reduce anxiety, decrease muscle tension, and

lower blood pressure and heart rate. They induce a state of altered consciousness and

give individuals a sense of control and peace of mind. Meditation, yoga, and other such

interventions may effectively relieve pain. One such exercise involves controlled

breathing. A coach speaks in a calm, clear voice, suggesting the subject begin by

breathing slowly and diaphragmatically, allowing the abdomen to rise slowly and the

chest to expand fully. Then, the coach suggests the subject locate an area of muscle

tension, contract the muscles in that area, and then relax them. As the subject relaxes,

pain perception and anxiety diminish.

Guided imagery is similar to relaxation exercises in that a coach leads subjects in a

calm, clear voice, often beginning with a relaxation exercise. The coach then suggests

subjects imagine themselves in some peaceful place where they experience various

sensory pleasures such as the warmth of the sun, the sound of ocean waves, and the

smell of salt water. The purpose of the exercise is to provide an experience of

relaxation and relief from stress and pain.

Distraction diverts the attention of individuals away from painful stimuli. When people

focus on something that gives pleasure, they are less likely to feel acute pain. This

phenomenon occurs because the reticular activating system briefly inhibits the

awareness of pain. Distraction works best for short acute pain, such as a needle stick.

Such things as listening to music, watching an intense scene on television, or describing

something of special interest may temporarily distract a person from pain. Distraction,

however, does not work for chronic, long-term pain.

Biofeedback is a method of treating chronic pain and other stress-related conditions. It

uses an electric device to gather information about physical responses and report them

back to clients. The information goes to the biofeedback machine by way of electrode

sensors placed on the person’s skin. It is displayed as visual signals on a monitor. As

clients watch these signals, they learn to control their responses.

Complementary and Alternative Medicine (CAM)

To relieve their pain, an increasing number of people in the United States are also

turning to theories and practices outside the realm of conventional Western medicine.

In 1991, the federal government established the Office of Alternative Medicine. In

1998, the agency became the National Center for Complementary and Alternative

Medicine (NCCAM), making the center one of 27 institutes and centers of the National

Institutes of Health within the Department of Health and Human Services. NCCAM

defines CAM as “a group of diverse medical and healthcare systems, practices, and

products that are not currently part of conventional medicine” (NCCAM, 2009a).

The mission of NCCAM is to explore “complementary and alternative healing practices

in the context of rigorous science…and [to] disseminate authoritative information to the

public and professionals” (NCCAM, 2007). In this context, “complementary” describes

practices used in conjunction with or to supplement conventional medical treatments,

and “alternative” means those that are used independently or in place of conventional

medicine. Practitioners of such techniques and practices often use the

term holistic because they view health and illness as affecting the whole person—body,

mind, and spirit.

The major categories of complementary and alternative medicine are:

o Biologic (herbal mixtures; macrobiotic diets; orthomolecular, such as

megadoses of vitamins, magnesium, melatonin, etc.)

o Energy fields (acupuncture, therapeutic touch, pulse fields, Reiki, etc.)

o Manipulative and body-based (chiropractic, lymphatic drainage, reflexology,

aromatherapy, deep-muscle massage, shiatsu, etc.)

o Mind-body (biofeedback, hypnosis, art therapy, prayer, etc.) (Diluzio &

Spillane 2002)

Biologic. Plants have been used to treat human ailments throughout history. Their

therapeutic effects are due to the chemical compounds they contain. Such chemicals

may be administered to patients by giving some part of a plant or by extracting or

synthesizing the essential chemical. When prepared in a purified form, the dose is more

precise than it can be from a plant. Some common active chemicals originally derived

from plants are: digitaloid found in the foxglove plant (digitalis), saponins found in

sarsaparilla (irritant laxatives), alkaloids found in nightshades (atropine), and alkaloids

found in the opium poppy (morphine) (McGuigan & Krug, 1942).

Energy fields. Such healing measures are based on theories about unseen forces in the

human body. Acupuncture, for instance, is based on an ancient Chinese theory that two

opposing forces, yin and yang, move along meridians in the body. When these forces

are out of balance, pain and illness result. There are at least 350 acupuncture points by

which energy flows are accessible. The theory posits that by stimulating these points

with very fine needles, the energy flow can be rebalanced and pain relieved (Mayo

Clinic, 2009; NCCAM, 2009b).

o Acupuncture (AH-q-punk-sher) is based on the belief that life forces or energy move through the body in specific paths. These paths are called meridians (mer-IH-d-uns). With acupuncture, a needle is put into the meridian that runs to the area where you have pain. This needle blocks the meridian which stops or decreases the pain.

o Touch energy therapies come from very old beliefs that life forces or energy move through the body in specific paths. Touch therapies believe disease may cause these paths to become blocked. The therapies use touch to help unblock these paths, and allow the energy to flow normally. Unblocking the paths may help you relax and decrease pain.

Chiropractic is a healthcare approach that focuses on the relationship between the

body’s structure—mainly the spine—and its functioning. Although practitioners may

use a variety of treatment approaches, they primarily perform adjustments to the spine

or other parts of the body with the goal of correcting alignment problems and

supporting the body’s natural ability to heal itself. People seek chiropractic care

primarily for pain conditions such as back pain, neck pain, and headache. Side effects

and risks depend on the type of chiropractic treatment used. Ongoing research is

looking at effects of chiropractic treatment approaches, how they might work, and

diseases and conditions for which they may be most helpful. (NCCAM, 2009c.)

Osteopathy is a medical specialty that combines traditional and nontraditional

medicine. Practitioners, called doctor of osteopathy (DO), practice traditional, science-

based medicine, and are licensed to perform surgery and prescribe drugs. They “take a

holistic view of the body as an integrated system and approach prevention, diagnosis,

and treatment by way of the musculoskeletal system” (Asher, 2007).

Biofeedback is a method of treating chronic pain and some stress-related conditions. It

uses an electric device to gather information about physical responses and report them

back to clients. The information goes to the biofeedback machine by way of electrode

sensors placed on the person’s skin. The machine displays information as visual signals

on a monitor. As clients watch the signals, they learn to control their responses.

.

SUMMARY

Pain, however, is much more than a physical sensation caused by a single entity. It is

subjective and highly individual, a complex mechanism with physical, emotional, and

cognitive components. Although there are myriad drugs to relieve pain, all have some

risk and cost. Fortunately, there are many nonpharmacologic interventions to reduce pain,

especially when used in conjunction with pharmacologic measures. Described as physical

and cognitive-behavioral interventions, many of these approaches are noninvasive, low-

risk, inexpensive, easily performed and taught, and within the scope of nursing practice.

Physical interventions give comfort, increase mobility, and alter physiologic responses.

Cognitive-behavioral interventions alter the perception of pain, reduce fear, give a greater

sense of control, and are considered holistic nursing practice.

BIBLIOGRAPHY

Brunner and suddarths ‘ medical surgical nursing”(2000); usa. Lippincott raven, 9th ed. 372-378.

Joyce M.Black. “medical surgical nursing”new delhi, (2005);

Elservier , 7th ed

1706-1724.

http://www.thenewstoday.info/2006/12/10/pain management . htm

http://www.nlm.nih.gov/medlinepluslency article/000077.htm.