Pain management

Pain and its physiology

Pain is a fundamental human experience that plays a crucial role in protecting health and well-being. It is the most common reason patients seek medical care, serving as an indicator of underlying health issues. Pain can arise from various causes, including structural damage, functional disturbances, or external injuries, acting as a warning signal that prompts medical attention and intervention.

From a physiological standpoint, pain involves intricate interactions between the nervous system, sensory receptors, and the brain. When tissues are damaged or at risk, nociceptors specialized nerve endings detect these changes and transmit signals to the spinal cord and brain. The brain then processes these signals, leading to the perception of pain. This mechanism is not random; it is a highly developed protective response designed to prevent further harm.

Pain also plays a vital role in motivating individuals to take action. It encourages behaviors such as seeking medical help, adjusting body movements, or making lifestyle changes to prevent worsening conditions. For example, acute pain from an injury may lead to immediate wound care, reducing the risk of infection, while persistent pain could indicate an underlying chronic condition that requires further assessment. It is essential to understand to manage pain by providing quality patient care. Recognizing different types of pain, assessing its severity, and implementing appropriate interventions can improve patient outcomes and enhance overall well-being.

Definition

Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain (IASP) offers the accepted medical definition of pain as: “An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.”

  Mc Caffery, a nurse and pioneer of pain management defined pain as : “Whatever the person experiencing the pain says it is, existing whenever the person says it does”

Pain has been defined as an, ‟unpleasant sensation usually associated with disease or injury” (Timby 2009). It causes physical discomfort that is a companied by suffering, which is the emotional component of pain.

 The American Pain Society coined the phrase “Pain: The 5th Vital Sign”

Pain is‟whatever the person says it is, and existing whenever the person says it does” (Margo Mc Caffery, 1998).

“It is not the responsibility of clients to prove that they are in pain; it is the nurses responsibility to believe them.” (Crisp & Taylor, 2005).

Pain is a complex and deeply personal experience, influenced by emotional, behavioral, cognitive, and physiological factors. It encompasses sensory dimensions such as time, intensity, emotion, cognition, and motivation, making it unique to each individual, as no two people experience pain in the same way.

Factors influencing pain perception and response

A. Physiological factors

1. Age

Pain perception and response differ across age groups due to variations in experiences, beliefs, and communication abilities. Young children, with limited exposure to pain and an underdeveloped ability to express discomfort, often struggle to articulate their feelings to caregivers. Their pain responses may be exaggerated or misunderstood, making assessment and management more challenging.

In contrast, older adults typically have a better understanding of pain and its implications. However, pain in the elderly is often underreported and untreated. Many seniors perceive pain as an inevitable part of aging and may not seek medical attention, fearing it could indicate a severe condition or lead to a loss of independence. Additionally, healthcare providers may overlook pain complaints in older adults, assuming it to be age-related rather than a condition requiring intervention. Recognizing these age-related variations is crucial for effective pain assessment and management.

ii. Gender

Research has shown notable differences in how men and women perceive and respond to pain. Women often report higher pain intensity, along with greater feelings of unpleasantness, frustration, and fear. However, studies suggest that anxiety plays a role in pain perception, as gender differences become less pronounced when anxiety levels are considered.

Men and women also differ in their pain tolerance and expression. While women tend to have a higher tolerance for pain, they are more likely to express their discomfort openly, making their pain more noticeable. In contrast, men often suppress or minimize their pain, maintaining greater control over their expressions. These variations highlight the influence of biological, psychological, and social factors in shaping pain perception and response, emphasizing the need for personalized pain management approaches.

iii. Attention and Distraction

The way individuals focus on pain can significantly influence how it is perceived. Increased attention to pain often heightens discomfort, as continuous awareness amplifies the body’s sensitivity to it. Psychological and emotional factors play a crucial role in this process, making pain feel more intense when it is constantly acknowledged.

Conversely, distraction has been shown to reduce pain by shifting focus away from discomfort. Engaging in mentally demanding activities can temporarily suppress pain perception. A common example is seen in athletes who sustain injuries during competitions but remain unaware of the pain until after the event. Their intense concentration, combined with an adrenaline rush, masks the pain until they are no longer engaged in the activity.

This phenomenon highlights the strong connection between the mind and pain perception. Understanding how attention influences pain can help in developing effective pain management strategies, such as cognitive distraction techniques, relaxation methods, and psychological interventions to reduce discomfort.

iv. Fatigue

Fatigue can intensify the perception of pain. When an individual is highly fatigued, even mild discomfort can become acutely painful. Fatigue not only heightens the sensation of pain but also reduces one’s ability to cope with it. For example, many people find that a foot ache, which may have been only mildly annoying during the day, becomes unbearable at night when there are fewer distractions and the mind focuses more on the discomfort.

B. Socio-cultural factors

i. Culture

Cultural norms significantly shape our behaviors, attitudes, and values, including how individuals perceive and respond to pain. From an early age, people learn from their surroundings what situations are considered painful and which reactions are deemed acceptable. These culturally learned beliefs differ widely, meaning individuals from different cultural backgrounds experiencing the same level of pain may express it differently. For instance, someone from one culture might describe the pain as “unbearable,” while someone from another culture might endure the pain quietly, able to face adversity calmly. For example, a child may grow up believing that a sports injury should hurt less than an injury from a car accident, even if the physical pain is similar.

ii. Ethnic variables

Ethnic variables play a significant role in how individuals perceive and react to pain, shaped largely by cultural expectations and social norms. The way people from different cultural backgrounds experience, express, and tolerate pain can differ greatly due to these cultural influences.

iii. Religious beliefs

Religious beliefs can significantly influence an individual’s experience of pain. In some religions, pain and suffering are viewed not as inherently negative but as a means of purification or atonement for personal and communal sins. For example, in Christianity, some believe that suffering can help purify the soul and bring individuals closer to God, much like the suffering of Jesus Christ on the cross.

iv. Environment

The environment plays a significant role in shaping an individual’s experience of pain. Factors such as the unfamiliarity of the healthcare setting, including the harsh lighting, noise, and constant activity in a critical care unit, can exacerbate the perception of pain. Additionally, the sense of powerlessness often felt when admitted to a medical facility can diminish an individual’s ability to effectively cope with pain, highlighting the influence of the environment on pain perception.

C. Psychological factors

1. Past pain experience

An individual’s past experience with pain significantly influences their perception of new pain. For some, having never encountered severe pain, there may be no fear of pain, and they may not fully grasp the intensity of the sensation. On the other hand, individuals who have endured severe pain in the past, especially without finding relief, may experience heightened fear and anxiety at the mere suggestion of new pain, often leading to feelings of despair and hopelessness. In general, those who have experienced more pain throughout their lives are more likely to anticipate future pain and demonstrate increased sensitivity to it.

ii. Anxiety and depression

Anxiety, particularly when linked to pain, can amplify a patient’s perception of pain. For example, a patient who underwent treatment for a severe leg injury six months ago and is now experiencing back pain may fear that the new pain is a sign of complications, causing anxiety that worsens the pain experience. Conversely, anxiety unrelated to the pain may distract the patient and potentially reduce their perception of pain. For instance, a mother hospitalized due to complications from abdominal surgery may experience less pain as her anxiety about her children increases, as her focus shifts away from her physical discomfort.

iii. Family and social support

Family and social support play a crucial role in managing pain and promoting emotional well-being. When individuals experience pain, whether physical or emotional, the presence of loved ones can significantly alleviate stress and improve their coping ability. Without the support of family or friends, pain can become more isolating and overwhelming, as the person may feel alone in their struggle. In contrast, having a supportive network of family and friends provides not only physical assistance, such as help with daily tasks, but also emotional comfort, which can be just as important in reducing the overall pain experience. For example, a patient recovering from major surgery, such as a hip replacement, may find the process less stressful and painful when surrounded by family members who offer encouragement and reassurance.

iv. Placebo effect

A placebo effect occurs when a person experiences a perceived improvement in their condition simply because they believe the treatment they are receiving will be effective, rather than due to the actual pharmacological or therapeutic properties of the treatment. This response is often linked to the natural endogenous production of endorphins, which are chemicals in the brain that play a role in pain relief, and the body’s descending pain control system. When a person expects relief, the brain may trigger the release of endorphins, resulting in a reduction in pain.

For example, studies have shown that patients who are informed that a medication is likely to relieve pain tend to experience more significant pain relief than those who are told the medication might not have any effect. This is because the belief in the treatment’s efficacy activates the brain’s pain-relieving mechanisms. Researchers have found that the way healthcare providers communicate with patients about treatment can significantly influence how patients perceive pain and respond to pain management strategies. The expectations set by verbal instructions can alter a patient’s behavior, enhancing their response to the treatment.

D. Spiritual factors

Spiritual beliefs play a significant role in how individuals perceive and cope with pain. For some, pain is seen as a test of endurance or a means of spiritual growth. In Hinduism, suffering is often linked to karma, where pain is believed to result from past actions and enduring it is thought to purify the soul.

For example, some individuals with chronic illnesses may choose to bear their pain without seeking medical relief, believing it to be a necessary spiritual experience. These perspectives demonstrate how faith and spirituality can shape pain tolerance and coping mechanisms.

Physiology of pain

According to Mc. Caffery and Pasero 1990 there are four process of physiology of pain which are:

1. Transduction: Pain transduction begins when nociceptors, the free nerve endings of primary afferent neurons, specifically C fibers and A-delta fibers, are activated by noxious stimuli. These stimuli typically arise from tissue damage or inflammation caused by trauma, surgery, infection, ischemia, or other pathological conditions. Nociceptors are widely distributed across somatic structures, such as the skin, muscles, connective tissues, bones, and joints, as well as visceral structures, including organs like the liver and gastrointestinal tract. While C fibers are associated with dull, aching, or burning pain, A-delta fibers transmit sharp, localized pain, reflecting their distinct roles in pain perception.
2. Transmission: After transduction, the pain signal is transmitted along the nociceptor fibers (A-delta and C fibers) to the dorsal horn of the spinal cord. From the spinal cord, the pain signal is relayed to the brainstem and then to higher brain centers, including the thalamus, which acts as a relay station. The signal continues its journey to the cortex for further processing.
3. Perception: This is the stage where the brain interprets the pain signals. The sensory cortex helps localize the pain and characterize its intensity, while the limbic system processes the emotional aspects of pain. The perception of pain can vary based on physiological, psychological, and social factors, influencing how the pain is experienced.
4. Modulation: This process involves the body’s ability to alter the pain experience, either amplifying or dampening the pain signal. Modulation occurs at multiple levels, particularly in the spinal cord and brain. Descending pathways from the brain can release inhibitory neurotransmitters (such as endorphins or serotonin) to decrease the transmission of pain, while other factors like stress or psychological state can influence the perception of pain.

Types/Classification of pain

A. Based on duration and intensity
 
Acute pain: An episode that is usually of a short period (1 second to less than 6 months) and has an immediate onset is often referred to as acute pain. This type of pain is typically protective, with an identifiable cause, and is associated with limited tissue damage and a pronounced emotional response. Acute pain resolves with or without treatment as the damaged area heals.
If acute pain remains unrelieved, it can progress to chronic pain, which persists beyond the normal healing period. Therefore, aggressive management of acute pain is crucial to prevent it from becoming chronic. For instance, the timely use of analgesics, physical therapy, or other pain management techniques can help reduce the risk of pain becoming persistent and more difficult to treat.
Examples of acute pain include:

• A sprained ankle or muscle strain.
• A cut or injury to the skin.
• Acute headaches such as migraines or tension headaches.
• Post-surgical pain during recovery.

Chronic pain: It is defined as pain that persists for a longer duration than the expected healing period, typically lasting for more than 6 months. Unlike acute pain, which is usually associated with a specific injury or illness, chronic pain may have no clear or identifiable cause and can continue even after the underlying injury has healed. Chronic pain can be constant or intermittent, and it may fluctuate in intensity.

•   Examples of chronic pain include:
• Osteoarthritis: Joint pain caused by wear and tear of cartilage.
• Back pain: Often caused by injury, degeneration, or postural issues.
• Neuropathic pain: Pain caused by nerve damage, such as in conditions like diabetic neuropathy
• Since chronic pain can significantly affect a person’s well-being, early diagnosis and appropriate management are essential to prevent worsening and improve the quality of life for those affected.

B. On the basis of origin

Cutaneous/Superficial pain

Origin: Arises from the skin or subcutaneous tissue.

Characteristics:

• Sudden onset with a sharp, stinging sensation.
• Gradual onset with a burning sensation.

Examples: Pain caused by a cut or burn on the skin.

Deep somatic pain

Origin: Arises from ligaments, tendons, muscles, joints, periosteum, nerves, and blood vessels.

Characteristics:

• Poorly localized.
• Often associated with inflammation.
• Typically lasts longer than cutaneous pain.

Examples: Rheumatoid arthritis, osteomyelitis, laceration, post-surgical pain, etc.

Visceral pain

Origin: Arises from the viscera (abdominal organs) or other internal organs within body cavities.

Characteristics:

• Initially diffuse and poorly localized.
• May become more localized over time.

Examples: Appendicitis, pain associated with cancer, bone fractures, or bone cancer.

Psychogenic pain

Pain experienced by an individual where the cause is emotional rather than physical.

Characteristics:

• Can be caused, increased, or prolonged by mental or emotional problems.

• Treatment:
  • Psychotherapy.
  • Antidepressants.
  • Non-narcotic analgesics.

C. On the basis of body area of experience

Radiating pain

Pain that is felt at its source and spreads to nearby tissues.

• Examples: Cardiac pain.

Referred pain

A type of visceral pain felt in an area distant from the site of the stimulus. It occurs in a part of the body far from the tissue causing the pain.

Characteristics:

• Pain perception is displaced from its origin.

Examples:

• Chest pain due to gastritis.
• Myocardial ischemia often felt as pain in the left arm, shoulder, or jaw rather than the heart.

Intractable pain

Pain that is highly resistant to relief, even with standard medical treatment.

• Examples: Pain associated with advanced malignancy.

Neuropathic pain

Pain resulting from damage or injury to nerve fibers in the peripheral nervous system or the central nervous system (CNS). It may occur without a stimulus, such as tissue damage.

• Characteristics:
  • Long-lasting and unpleasant.
  • Described as burning, numbness, stabbing, “needles,” dull, or electric shock-like sensations.
• Examples:
  • Spinal nerve root compression.
  • Trigeminal neuralgia.

Phantom limb sensation

It refers to the phenomenon where individuals who have undergone an amputation continue to feel sensations in the body part that is no longer physically present. This can occur after the amputation of a limb, breast, or even other parts of the body. The sensations can range from tingling, itching, or even pain, as if the missing body part were still there. The sensations can sometimes feel as though the limb is in a particular position or that it is moving, despite its absence.

Assessment of pain

Pain assessment is a complex process that depends on its causes, severity, and type, as well as the individual’s unique experience. The intensity of the response to a pain stimulus is largely subjective, meaning only the person experiencing the pain can most accurately define its severity. However, objective measures, such as physiological changes and clinical observations, also play a critical role in evaluating pain. A comprehensive pain assessment incorporates both subjective reports from the individual and objective findings from healthcare professionals to ensure accurate diagnosis and effective management.

1. Subjective assessment
2. Objective assessment

A. Subjective assessment

Pain history

When taking a pain history, it is essential to provide the patient with the opportunity to express themselves in their own words. This approach allows the nurse to understand what the pain means to the client and how they are coping with it. A detailed pain history helps in identifying the nature, causes, and impact of the pain, which are critical for planning effective care and management.

• Onset and duration of occurrence:
  • When did the pain start?
  • Is the pain constant or intermittent?
  • How long does each episode last?
• Location:
  • Where is the pain located?
  • Does it radiate to other areas of the body?
• Intensity:

1. Use of pain intensity scale is an easy and reliable method of determining the client’s pain intensity.
2. Such scale provides consistency for nurses to communicate with their clients and other health care providers
3. Most scales are either 0 to 5 or 0 to 10 range with “0” indicating no pain and the “highest” number indicating the worst pain possible for an individual
4. How severe is the pain on a scale of 0 to 10?

Currently used scales are: –

1. Numerical Rating Scale: A numerical scale range from 0 to 10. The word “no pain” appear by the “0” and “worst pain possible” is found by the “10”.

Here;

• 0= no pain
• 1 to 2= mild pain
• 3 to 5=moderate pain
• 6 to 8=severe pain
• 9 to 10=worst pain possible
• Patient is asked to choose a number from 0 to 10 that best reflects his/her level of pain.

b. Descriptive / Verbal Rating Scale: The patient selects a word or phrase that best describes their pain level, such as:

• No pain
• Mild pain
• Moderate pain
• Severe pain
• Very severe pain
• Worst pain imaginable

c. Visual Analogue Scales(VAS): A straight line, usually 10 cm long, is used where:

• One end represents “no pain”
• The other end represents “worst possible pain”
• The patient marks a point on the line that corresponds to their level of pain. The distance from “no pain” to the marked point is measured for scoring.

d. Wong – Baker Faces Pain Rating Scales: A series of facial expressions ranging from a happy face (no pain) to a crying face (worst pain) is shown to the patient. The patient selects the face that best represents their pain. This tool is particularly useful for children and patients with communication difficulties.

• 0: No pain (smiling face)
• 2: Hurts a little bit (slightly frowning face)
• 4: Hurts a little more (frowning face)
• 6: Hurts even more (more intense frown)
•  8: Hurts a whole lot (nearly crying face)
• 10: Hurts the worst (crying face)

5. How long does each episode last?

• It is essential to assess fluctuations in pain levels, as some conditions cause pain that worsens in the morning (e.g., arthritis) or at night (e.g., neuropathic pain).

• Quality:

What does the pain feel like? (e.g., sharp, dull, stabbing, burning, throbbing)

• Precipitating factors:
  • What activities or events seem to trigger the pain?
  • Is it associated with specific movements, positions, or situations?
• Alleviating factors:
  • What helps relieve the pain? (e.g., rest, medications, hot/cold compress)
  • Are there specific strategies the patient uses to cope with the pain?
• Effect on Activities of Daily Living (ADLs):
  • How does the pain affect daily routines, such as walking, sleeping, or working?
  • Are there any limitations or challenges the pain has caused in maintaining normal activities?

By collecting and documenting this information, healthcare providers can better understand the patient’s pain experience and design an appropriate pain management plan.

B. Objective Assessment

Vital signs and physical examination

• Monitor vital signs (e.g., blood pressure, pulse, respiratory rate, and temperature).
• Conduct a physical examination and observe for non-verbal responses to pain.

Behavioral effects

• Assess the following:
  • Verbalization: Complaints of discomfort or expressions of pain.
  • Vocal response: Sounds like moaning, groaning, crying, grunting, or screaming.
  • Facial and body movements: Indicators such as clenched teeth, tightly shut eyes, open somber eyes, or biting of nails.
  • Social interactions: Changes in social engagement, withdrawal, or irritability.
• Note: Facial expression is often the first indication of pain and may sometimes be the only observable sign.

Physiological responses

• Variability: Physiological responses differ based on the pain’s origin and duration.
• Acute pain response: In the early stages of acute pain, the sympathetic nervous system is stimulated, causing:
  – Increased blood pressure.
  – Elevated pulse rate.
  – Faster respiratory rate.
  – Pallor (pale skin).
  – Diaphoresis (excessive sweating).
  – Pupil dilation.
   

Non-pharmacological pain relief interventions

Non-pharmacological pain relief interventions focus on alternative methods to alleviate pain without the use of medication. These methods are divided into physical interventions and mind-body (cognitive-behavioral) interventions.

1. Physical Interventions:

a. Cutaneous Stimulation: According to the Nursing Interventions Classification (NIC), cutaneous stimulation involves stimulating the skin and underlying tissues to decrease undesirable symptoms such as pain, muscle spasms, or inflammation.

• Examples: Hot and cold applications, massage, and pressure. These methods can relax or distract patients from their pain.

b. Massage: Massage involves the manipulation of superficial and deeper layers of muscles and connective tissues to promote relaxation, enhance function, decrease muscle tension, and alleviate anxiety.

• Benefits: Massaging for 3 to 5 minutes can relax muscles, promote sleep, and provide comfort.
• Contraindications: Massage should be avoided in areas of skin breakdown.

c. Heat and cold applications:

• Heat applications: Include warm baths, heating pads, and warm sitz baths. These relieve pain by increasing blood flow to inflamed or infected areas.
• Cold applications: Include ice packs and cold sitz baths. These penetrate muscles, prevent bleeding, and reduce edema through vasoconstriction.

d. Transcutaneous Electrical Nerve Stimulation (TENS): TENS involves applying low-voltage electrical stimulation to identified pain areas, acupuncture points, or peripheral nerve regions.It uses a battery-powered pulse generator, lead wires, and electrodes. The electrical current is sent between the electrodes placed on either side of the injured area.

• Uses: Effective for treating acute postoperative pain, labor pain, and cancer-related pain.
• Contraindications: Should not be used by clients with pacemakers, arrhythmias, or over areas of skin breakdown.

e. Immobilization: Restricting the movement of painful body parts (e.g., arthritis-affected joints or traumatized limbs) can manage acute pain episodes.

• Splints or supportive devices should hold joints in optimal functional positions.
• Devices should be removed regularly for range-of-motion exercises to prevent complications such as joint contractures, muscle atrophy, and cardiovascular problems.

2. Mind-body (Cognitive-behavioral) interventions:
a. Distraction: Distraction diverts a client’s attention to reduce pain awareness and increase tolerance. It is effective for short, intense pain episodes.
Examples: Used during invasive procedures or while waiting for analgesics to take effect.
Types of distraction:
Visual distraction:
– Reading or watching TV.
– Watching an interesting game.
– Guided imagery.
Auditory distraction:
– Listening to humor.
– Enjoying music.
Tactile distraction:
– Slow rhythmic breathing.
– Massage.
– Holding pets or toys.
Intellectual distraction:
– Solving crossword puzzles.
– Playing card games.
-Engaging in hobbies such as writing stories or poems.

b. Hypnosis:

• Hypnosis is a heightened state of focused concentration with minimal distraction.
• It prevents pain stimuli from penetrating the conscious mind, offering an alternative method for pain management.
• Uses: Helps not only in controlling pain but also in altering body functions and changing lifestyle habits.

Pharmacological pain relief interventions

Pharmacological interventions for pain relief involve the use of medications to manage acute and severe pain effectively. These interventions are categorized based on the type of medication used:

1. Analgesics

Classification:

• Non-opioids: NSAIDs (e.g., Paracetamol)
• Weak opioids: (e.g., Codeine, Tramadol)
• Strong opioids: (e.g., Morphine, Pethidine)
• Adjuvants: Anxiolytics, antidepressants, corticosteroids (e.g., Diazepam, Alprazolam, Amitriptyline, Dexamethasone, Prednisolone)

2. Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

Characteristics:

• NSAIDs possess analgesic, antipyretic, and anti-inflammatory properties.
• They do not cause CNS depression, physical dependence, or abuse liability but are considered weaker analgesics.
• Common forms: Tablets, syrup, injections, gels.

Classification of NSAIDs:

Non-selective COX inhibitors:

• Salicylates: Aspirin
• Propionic acid derivatives: Ibuprofen
• Anthranilic acid derivatives: Mephenamic acid
• Pyrrolo-pyrrole derivatives: Ketorolac

Preferential COX-2 inhibitors: Nimesulide, Meloxicam

Selective COX-2 inhibitors: Celecoxib, Parecoxib

Analgesic-antipyretic with poor anti-inflammatory action:

• Para-aminophenol derivative: Paracetamol
• Benzoxazocine derivative: Nefopam

Adverse effects of NSAIDs:

• Gastrointestinal: Irritation, erosion, peptic ulcer, gastric bleeding, perforation.
• Renal: Sodium-water retention, chronic renal failure, nephritis.
• Hepatic: Rare hepatic failure.
• CNS: Headache, mental confusion, seizure precipitation.
• Hematological: Bleeding, thrombocytopenia, hemolytic anemia.
• Others: Asthma exacerbation, nasal polyposis, skin rashes, pruritus, angioedema.

3. Opioid analgesics

Mechanism of action:

Opioids interact with specific receptors (μ, ĸ, and ɗ) located in the CNS and peripheral tissues. The μ receptor is critical in sensory processing, modulating nociceptive stimuli. Opioids primarily exert inhibitory effects and are categorized into full μ agonists, partial agonists, and mixed agonist-antagonists.

Examples of Opioid analgesics:

• Natural opium alkaloids: Morphine, Codeine
• Semisynthetic opiates: Diacetylmorphine (Heroin), Pholcodeine
• Synthetic opioids: Pethidine, Fentanyl, Tramadol, Methadone

Routes of administration:

• Oral: Simplest and least expensive method.
• Rectal: Alternative when oral administration is not feasible.
• Parenteral: Subcutaneous, intravenous, or intra-spinal administration for severe cases.
• Unlike opioids, NSAIDs and acetaminophen do not produce tolerance, physical dependence, or psychological dependence.

4. Adjuvant pain medicines

Adjuvant analgesics are medications that enhance the efficacy of opioids, address concurrent symptoms that exacerbate pain, and provide independent analgesia for specific types of pain. These drugs can be used across all stages of the analgesic ladder.

Examples:

Acetaminophen:

• Possesses analgesic and antipyretic properties but lacks anti-inflammatory action.
• Additive analgesic effects with NSAIDs and opioids.
• Overuse may lead to liver toxicity; doses should not exceed 4 grams per 24 hours.

Corticosteroids:

• Exhibit anti-inflammatory effects, mood elevation, antiemetic activity, and appetite stimulation.
• Reduce pain by minimizing swelling and nerve compression.

Anticonvulsants:

• Examples: Carbamazepine, valproate, clonazepam, phenytoin, gabapentin.
• Used to manage neuropathic pain, especially with shooting or lancinating qualities.

Tricyclic antidepressants:

• Examples: Amitriptyline, desipramine, imipramine, nortriptyline.
• Effective for general pain management and neuropathic pain by enhancing inhibitory modulation of nociceptive impulses.

Bisphosphonates:

• Examples: Pamidronate, calcitonin.
• Used for bone pain associated with metastases by inhibiting osteoclast activity and bone resorption.

Analgesic combinations:

Examples:

• Aspirin + Paracetamol = 1000 mg
• Codeine combined with aspirin or paracetamol for enhanced efficacy.

5. Methods and routes of drug administration

• Patient-Controlled Analgesia (PCA): Allows patients to self-administer predetermined doses of analgesics.
• Local analgesics: Examples: lidocaine, bupivacaine.
• Topical analgesics: Examples: diclofenac gel, lignocaine patch.
• Regional anesthesia: Examples: Epidural, pudendal, and spinal block.

6. Regional Anesthesia

Common modes of administration:

1. Epidural anesthesia:

Narcotics and local anesthetics administered via infusion or bolus.

Examples:

• Morphine (0.01%): 5-10 mL/h
• Fentanyl (0.001%): 5-10 mL/h
• Bupivacaine (0.05-0.1%): 5-10 mL/h
• Ropivacaine (0.1%): 5-10 mL/h

Adverse effects: Urinary retention, motor block, hypotension

2. Peripheral Nerve Blocks:

• Utilized with general anesthesia or independently.
• Long-acting anesthetics: Bupivacaine, Ropivacaine.
• Additives like dexamethasone or methylprednisolone extend analgesic duration.
• Common sites: Brachial plexus block (above/below clavicle) and leg block

3. Local infiltration analgesia:

• Involves systematic infiltration of a mixture (e.g., ropivacaine, ketorolac, epinephrine) around the surgical site.
• Benefits: Preserves motor function post-surgery, especially in knee and hip arthroplasty.

WHO Pain management ladder

The WHO Pain Management ladder was first published in 1986 in the handbook. Since its introduction, the ladder has served as a guide for clinicians worldwide in managing both cancer and non-cancer pain.

Some adjuvants, such as acetaminophen, NSAIDs, tricyclic antidepressants, and antiepileptics, have intrinsic analgesic properties and can be used alone or in combination as co-analgesia.

Original three-step ladder

1. First step – mild pain: Non-opioid analgesics, such as NSAIDs or acetaminophen, with or without adjuvants.
2. Second step – moderate pain: Weak opioids (e.g., hydrocodone, codeine, tramadol) with or without non-opioid analgesics and with or without adjuvants.
3. Third step – Severe and persistent pain: Potent opioids (e.g., morphine, methadone, fentanyl, oxycodone, buprenorphine, hydromorphone, oxymorphone) with or without non-opioid analgesics and with or without adjuvants.

C. Surgical interventions

1. Dorsal Rhizotomy

Surgical cutting of the dorsal nerve roots as they enter the spinal cord.

• Purpose: Effective for relieving localized acute pain in the area supplied by the nerve root and deep visceral pain.
• Outcome: Patients lose pain sensation while retaining full motor function.

2. Spinal cordotomy

• Procedure: May be performed openly or percutaneously.
• Mechanism: Anterior spinothalamic tracts, responsible for pain and temperature sensation, are sectioned to relieve severe pain associated with advanced malignant disease.
• Considerations:
  • Often requires a bilateral approach.
  • Rarely employed due to limited evidence of efficacy.
  • Provides temporary relief for conditions such as severe burns and shingles.

Radiotherapy

• Purpose:
  • Relieves pain by suppressing or reducing tumor size, thereby reducing pressure on nerve endings.
• Application: Commonly used in palliative care for pain management.

Nurse’s role in pain management

1. Establish a therapeutic relationship

• Believe the patient’s description of their pain experience.
• Listen actively and allow the patient to verbalize their feelings.
• Encourage the patient to use their own words to describe the pain.

2. Establish a 24-Hour pain profile

• Assessments:
  • Location: Extent, internal, external, or both.
  • Character and intensity: Acute vs. chronic.
  • Severity: Mild or severe; sudden or insidious onset.
  • Duration: How long the pain lasts.
  • Precipitating factors: Triggers for the pain.
  • Associated manifestations: Alleviating or aggravating factors.

3. Teach patients about pain and its relief

• Explain the quality and location of anticipated pain, such as before an uncomfortable procedure.
• Educate patients on using slow rhythmic breathing to promote relaxation.
• Explain the effects of analgesics and the benefits of preventive approaches.
• Demonstrate splinting techniques to reduce pain.

4. Reduce anxiety and fears

• Provide reassurance.
• Offer distractions.
• Spend quality time with the patient.

5. Provide comfort measures

• Ensure proper positioning.
• Maintain a well-ventilated and quiet room.
• Offer back rubs.
• Allow the patient sufficient rest.

6. Administer pain medication

a. Use preventive approach:

• When pain is expected to persist for most of the day, a regular schedule is preferable as-needed administration.
• Smaller doses can be given to alleviate mild pain or prevent its occurrence.
• Regular administration ensures more complete pain relief and reduces the number of hours spent in pain.
• Helps prevent addiction.

b. Patient-Controlled Analgesia (PCA): Allows patients to self-administer analgesics as needed, within prescribed limits.

7. Plan for alternative methods of pain relief: Complementary therapies, such as acupuncture, massage, and relaxation techniques, can supplement traditional pain management approaches.

References:

1. Berman, A., Snyder, S., & Frandsen, G. (2020). Kozier & Erb’s Fundamentals of Nursing: Concepts, Process, and Practice. Pearson Education.
2. McCaffery, M., & Pasero, C. (1999). Pain: Clinical Manual. Elsevier Health Sciences.
3. Potter, P. A., Perry, A. G., Stockert, P. A., & Hall, A. (2020). Fundamentals of Nursing. Elsevier Health Sciences.
4. National Institute of Nursing Research (NINR). (2023). Non-Pharmacological Approaches to Pain Management. Retrieved from www.ninr.nih.gov.