Medications for Pain Management Chapter 17 Medications for Pain Management

Chapter 17 Lesson 17.1

Learning Objectives Explain why there are so many rules about how narcotics and related analgesic drugs may be given Compare and contrast drug tolerance and drug addiction Evaluate different forms of narcotic agonists and narcotic agonist-antagonists in their ability to control pain

Learning Objectives (cont.) List medications commonly used for the treatment of moderate to severe pain List behaviors that would make you believe a patient is addicted to a drug.

Opioids Two Forms Classification of Action Natural: from opium Synthetic: man-made Classification of Action Agonist Partial agonist Agonist-antagonist Narcotics, or opioids, are substances that produce stupor and are used to treat severe pain. Natural opioids come from opium, which in unripe seed capsules of the poppy plant. Opium contains chemicals such as morphine and codeine. Heroin chemically breaks down into morphine also. Synthetic, or man-made drugs, were developed in an attempt to make drugs less addictive. Unfortunately, these drugs are just as potent but still are used because they do not have all of the effects of opioids. Opioids would not be used for mild to moderate pain or chronic pain. Nonnarcotics such as ibuprofen (Motrin) or acetaminophen (Tylenol) would be indicated instead.

Opioids (cont.) Agonist Partial agonist Agonist-antagonist Binds with the receptor(s) to activate and produce the maximum response of the individual receptor Partial agonist Produces a partial response Agonist-antagonist Acts as an agonist at one type of receptor and as a competitive antagonist at another type of receptor The classifications and mechanisms of action are shown. The mechanisms of action for opioids is determined by where the drug binds to specific opioid receptor sites inside and outside the central nervous system. The primary opioid receptors in the CNS are mu, kappa, delta, and sigma receptors. Most analgesia is associated with the mu, kappa, and delta receptors. Most opioid action takes place at the mu and kappa receptors. Stimulation of the sigma receptors produces the most unwanted side effects.

Opioids (cont.) Morphine Codeine, hydrocodone, oxycodone Hydromorphone Uses Acute care Hospice Codeine, hydrocodone, oxycodone Office or clinical setting Hydromorphone Severe pain unrelieved by morphine Morphine is the main opioid drug to which all other pain management drugs are compared. Table 17-2 shows equivalent doses of opioid analgesics as compared to morphine. Codeine, hydrocodone, and oxycodone are often used in combination with acetaminophen (Tylenol) for pain relief. Hydromorphone is the most potent opioid listed and is used only if severe pain is unrelieved with morphine. What are the side effects of opioids?

Pain “An unpleasant sensation or emotion that produces or might produce tissue damage.” - International Association for the Study of Pain (IASP) Two Types Acute Chronic Pain is subjective in nature. No one can truly experience another’s pain. People also vary in their pain perceptions. “Pain is whatever the patient says it is.”—Margo McCaffrey, RN, Nurse Researcher Acute pain is usually related to an injury, such as trauma, recent surgery, or infection, and disappears within an expected length of time. Chronic pain is any pain that continues beyond the usual course of the acute injury process. Many people, such as those with chronic diseases such as rheumatoid arthritis or cancer, live with chronic pain. Pain is the main reason people seek medical care. Is psychologic pain real?

Pain Measurement Scales

Wong-Baker Faces Pain Rating Scale

Pain (cont.) Factors That Produce Pain: An unpleasant stimulus that affects nerve endings and sets off electrical activity Electrical signals that pass the stimulus along nerve endings to the spine Signals that are carried to the brain Development of behavioral, psychologic, and emotional responses in the brain Researchers believe there are four things needed for pain to occur. Different types of nerve fibers carry different pain signals. Different types of measuring scales are used to put an objective rating on a subjective event. This helps the healthcare provider assess how the patient is perceiving the current symptoms in relationship to past pain occurrences.

Pain (cont.) Tolerance Dependence Addiction The same amount of a drug produces a decreased effect over time Dependence A state in which the body will show withdrawal symptoms if the drug is stopped or reduced Addiction The uncontrollable need to have and use a drug for nonmedical reasons All opioids cause tolerance and dependence. These are not the same as abuse. Withdrawal symptoms are changes in the body or mind, such as nausea or anxiety, that occur when a drug is stopped or reduced after regular use. Tapering, or gradually lowering a drug’s dosage, can lessen the symptoms of withdrawal. How do people describe the sensations experienced when they severely decrease their caffeine intake or cigarette use? Would these be examples of tolerance, dependence, or addiction?

Narcotic Agonist Analgesics Action Prevent pain perception in the central nervous system Produce analgesia, sleepiness, euphoria, unclear thinking, slow breathing, produce miosis, decreased peristalsis, reduced cough reflex, and hypotension Uses Treat moderate to severe pain The nerves that act have opioid receptors in the CNS (substantia gelatinosa [gray matter] of the spinal cord, brainstem, reticular formation, thalamus, and limbic system) and interact with the nerves of the autonomic nervous system that carry pain messages, which produce changes in the person’s reaction to pain. Narcotic agonist analgesics interfere with this CNS response. Miosis refers to the pupil of the eye constricting or getting smaller. What are some situations in which these medications would be used? Has anyone ever taken one of these drugs? How did you feel?

Narcotic Agonist Analgesics (cont.) Adverse Reactions Bradycardia, slowed breathing Hypotension, fainting Anorexia, constipation Confusion, euphoria Dry mouth, vomiting Pruritus, skin rash There are many side effects of narcotic agonists. The most common side effects are listed above. Geriatric patients are more susceptible to these reactions and overdose. In an overdose situation, respirations may fall below 12 per minute. Which drug is administered to counteract the effect of narcotic agonists? Other symptoms of overmedication include sedation, coma, miosis, oliguria, clammy skin, and hypothermia. Chronic overdose symptoms (seen in drug abusers) include very small pupils, constipation, mood changes, reduced level of alertness, skin infections, pruritus, needle scars, and abscesses. Respiratory rate and sleepiness are the most closely watched symptoms of overdose.

Patient-Controlled Analgesia Used when a continuous infusion of opioids is required Pump is calibrated to ordered dose and frequency Patient is able to self-administer pain med by pushing control button Pump can be programmed to deliver an hourly rate PCAs, or patient-controlled analgesia pumps, are used to deliver opioids at a constant rate (basal rate) per hour, or when the patient decides he or she requires the medication. A “lock out” mechanism on the pump allows the patient to self-administer a dose within a specified time period. The pump “counts” patient “attempts” and “injections” received. The nurse is able to read the pump history to determine whether the pain medication is adequate. The patient has to be able to understand how to push the controls to self-administer an injection. PCAs are not desirable for patients who are confused or very young.

Patient-Controlled Analgesia

Patient-Controlled Analgesia

Narcotic Agonist Analgesics (cont.) Drug Interactions Many drugs increase or decrease effects Nursing Implications Patient Teaching Drugs that increase the effects of narcotics include other narcotic agonist analgesics, alcohol, antianxiety agents, barbiturates, anesthetics, nonbarbiturate sedative-hypnotics, phenothiazines, skeletal muscle relaxants, and tricyclic antidepressants.

Narcotic Agonist-Antagonist Analgesics Action Act on chemicals at specific nerve sites in the CNS, possibly in the limbic system Produce analgesia, euphoria, and respiratory and physical depression Uses Relief of moderate to severe pain Presurgical anesthesia Active labor Pain assessment and monitoring is crucial. Some organizations have called for pain assessment to be the “fifth” vital sign, but this is not universal. There are many classifications of pain and scales to use. Three different rating scales are shown in Figure 17-1 of your text.

Narcotic Agonist-Antagonist Analgesics (cont.) Adverse Reactions Bradycardia or tachycardia Hypertension or hypotension Changes in mood, confusion, nervousness Blurred vision, dizziness, headache Weakness, nystagmus, syncope, tingling Tinnitus, tremor, unusual dreams Nausea, vomiting, dry mouth, constipation The Agency for Health Care Policy and Research (AHCPR) clinical practice guidelines include the following mnemonic to help remember the principles of pain assessment: A-A-B-C-D-E-E. Refer to your text to help you review what each letter represents.

Narcotic Agonist-Antagonist Analgesics (cont.) Drug Interactions Caution with alcohol and CNS depressants Nursing Implications Patient Teaching What teaching points will you reinforce with a patient taking narcotic agonist-antagonists?

Nonnarcotic Centrally Acting Analgesics Action Act at the level of the brain to control mild or moderate pain Uses Mild to moderate pain Used in combination products for pain alone or when pain and fever are present

Nonnarcotic Centrally Acting Analgesics (cont.) Adverse Reactions Postural hypotension, dizziness Disorientation, euphoria, headache Light-headedness, minor visual disturbances Sleepiness, slurring of speech, weakness Skin rashes, stomach or abdominal pain Dry mouth, nausea, vomiting, chills Difficulty urinating, stuffy nose Listed are the more common adverse reactions to nonnarcotic centrally-acting analgesics. Overdose of the medications produces extreme sleepiness and slowed breathing. Elderly and weakened patients may react more strongly. Cyanosis and low oxygen levels are present because of the slow breathing rate, hypotension, and weak heart function. Hepatotoxicity also may occur in alcoholics who use the drug acetaminophen (Tylenol).

Nonnarcotic Centrally Acting Analgesics (cont.) Drug Interactions Nursing Implications Patient Teaching These medications have CNS depressant effects that add to those of other depressants (e.g., alcohol, sedative-hypnotics, tranquilizers). These products tend to have fewer chemical interactions with other drugs than narcotics. What are the nursing implications the LPN/LVN would need to consider before and after administration of these medications? What are the key points that should be emphasized when teaching patients and families about these medications? Why should the additional use of OTC medications be a concern?