14 Drugs for Pain Control

Directory Classroom Response System Lecture Note Presentation

Question 1 The nurse understands that pain signals begin at the ______ and proceed through the central nervous system.

Question 1 Choices Spinal cord Viscera Nociceptors Substance P

Question 1 Answer Spinal cord Viscera Nociceptors Substance P

Question 2 The patient is experiencing opioid dependency. Which drug is used to treat this condition?

Question 2 Choices Oxycodone hydrochloride (OxyContin) Propoxyphene hydrochloride (Darvon) Hydromorphone hydrochloride (Dilaudid) Methadone (Dolophine)

Question 2 Answer Oxycodone hydrochloride (OxyContin) Propoxyphene hydrochloride (Darvon) Hydromorphone hydrochloride (Dilaudid) Methadone (Dolophine)

Question 3 When a patient is receiving an NSAID, the nurse must assess the patient for:

Question 3 Choices GI upset and bleeding Urinary retention Blurred vision Anorexia, headache

Question 3 Answer GI upset and bleeding Urinary retention Blurred vision Anorexia, headache

Question 4 The patient is on sumatriptan (Imitrex) for migraines. For which of the following should the nurse instruct the patient to notify his physician immediately?

Question 4 Choices Chest pain GI upset Bleeding Lethargy

Question 4 Answer Chest pain GI upset Bleeding Lethargy

Learning Outcomes Relate the importance of pain assessment to effective pharmacotherapy. Explain the neural mechanism for pain at the level of the spinal cord. Explain how pain can be controlled by inhibiting the release of spinal neurotransmitters.

Learning Outcomes Describe the role of nonpharmacologic therapies in pain management. Compare and contrast the types of opioid receptors and their importance to pharmacology. Explain the role of opioid antagonists in the diagnosis and treatment of acute opioid toxicity.

Learning Outcomes Describe the long-term treatment of opioid dependence. Compare the pharmacotherapeutic approaches of preventing migraines to those of aborting migraines.

Learning Outcomes For each of the major drug classes, know representative drug examples, and explain the mechanisms of drug action, primary actions, and important adverse effects for each. Categorize drugs used in the treatment of pain based on their classifications and mechanisms of action.

Pain assessment is the first step to pain management. Core Concept 14.1 Pain assessment is the first step to pain management.

Pain Subjective experience Termed acute or chronic Source Nociceptor pain Injury to the tissue Somatic – sharp localized

Pain Visceral – dull, throbbing, aching, generalized Neuropathic Pain Direct injury to the nerve Burning, shooting, numb

Pain Assessment First step in pain management Several numerical scales and survey instruments are available Need to know Location Severity Type Duration Effect on daily life

Concept Review 14.1 What questions would you ask to identify a patient’s type of pain? How would you distinguish between acute pain and chronic pain? Which is the most difficult type of pain to treat?

Core Concept 14.2 Nonpharmacologic techniques assist patients in obtaining adequate pain relief.

Nonpharmacologic Pain Management Acupuncture Biofeedback therapy Massage Heat or cold packs Meditation Relaxation therapy Art or music therapy

Nonpharmacologic Pain Management Imagery Chiropractic Hypnosis Therapeutic touch Transcutaneous electrical nerve stimulation (TENS) Energy therapies such as reiki and qi gong

Other Therapies Radiation Therapy - shrinks solid tumors that may be pressing on nerves Surgery - reduce pain by removing part of or the entire tumor Nerve Block - injection of alcohol or other neurotoxic substance into neuronal tissue irreversibly stop impulse transmission along treated nerves

Core Concept 14.3 Pain transmission processes allow several targets for pharmacologic intervention.

Targets Nociceptors - free nerve endings located throughout the entire body. Several targets where medications can work Two main classes of pain medications Nonsteroidal anti-inflammatory drugs (NSAIDs) act at the peripheral level Opioids act within the CNS.

Figure 14.1 Neural pathways for pain

Concept Review 14.2 What is a nociceptor? Consider substance P and endogenous opioids, and describe how pain can be regulated.

Core Concept 14.4 Opioid analgesic medications exert their effects by interacting with specific receptors.

Opiods Natural or synthetic morphine-like substance Responsible for reducing severe pain Narcotic substance - produce numbness or stuporlike symptoms Drugs of choice for moderate to severe pain that cannot be controlled with other classes of analgesics.

Figure 14.2 Opioid receptors

Concept Review 14.3 Distinguish between the following terms: opioid, opiate, and narcotic. Name six classes of opioid receptors and identify those that are connected with analgesia.

Core Concept 14.5 Narcotic opioids have multiple therapeutic effects including relief of severe pain.

Effects of Opiates Positive Severe pain relief Suppress the cough reflex Slowing GI motility Sedation

Effects of Opiates Negative Respiratory depression Sedation Nausea and vomiting.

Patient Controlled Analgesia (PCA) Delivered with Infusion Pump Limits set to prevent overdose Patient self-medicates by pushing button

Combination Medications Opioids and nonnarcotic analgesics Single tablet or capsule Work synergistically to relieve pain Dose of narcotic can be kept small Minimizes negative effects

Popular Combination Analgesics Vicodin(hydrocodone, 5 mg;acetaminophen, 500 mg) Percocet(oxycodoneHCl,5mg;acetaminophen,325 mg) Percodan (oxycodone HCl, 4.5 mg; oxycodone terephthalate, 0.38 mg; aspirin, 325 mg)

Popular Combination Analgesics Darvocet-N 50 (propoxyphene napsylate, 50 mg; acetaminophen, 325 mg) Empirin with Codeine No. 2 (codeine phosphate, 15 mg; aspirin, 325 mg) Tylenol with Codeine (single dose may contain from 15 to 60 mg of codeine phosphate and from 300 to 1,000 mg of acetaminophen

Opioid Antagonists Substances that prevent the effects of opioid agonists “Competitive antagonists” Compete with opioid agonists for access to the opioid Receptor site. Acute opioid intoxication is a medical emergency. Respiratory depression Naloxone (Narcan)

Opioids with Mixed Agonist–Antagonist Activity Stimulate the opioid receptor causing analgesia. Withdrawal symptoms/adverse effects Not as intense partial activity of receptor subtypes

Opioids with Mixed Agonist–Antagonist Activity Methadone (Dolophine) Treats opioid dependence Buprenorphine (Subutex) Newer option Given sublingual

Table 14.2 (continued) Opioids for Pain Management

Table 14.2 (continued) Opioids for Pain Management

Core Concept 14.6 Nonsteroidal anti-inflammatory drugs are the drugs of choice for inflammatory pain.

NSAIDs Antipyretic (antifever) Anti-inflammatory Analgesic (pain-reducing) properties Drugs of choice for mild to moderate pain associated with inflammation. Act by inhibiting pain mediators at the nociceptor level.

COX Inhibitors Prostaglandins Formed by cyclooxygenase type one (COX-1) and cyclooxygenase type two (COX-2). Aspirin inhibits both COX-1 and COX-2.

COX Inhibitors COX-2 enzyme More specific for cause pain and inflammation COX-2 inhibitors developed for specific pain relief. VIOXX (off the market), Celebrex

Acetaminophen Nonopioid analgesics Not classified as NSAIDs Equally effective as aspirin and ibuprofen ALso used to reduce fever.

Centrally Acting Drugs Clonidine (Catapres) Tramadol (Ultram) Weak opioid activity Not thought to relieve pain by this mechanism Ziconotide (Prialt)

Figure 14.3 Mechanisms of pain at the nociceptor level

Table 14.3 (continued) Nonopioid Analgesics

Table 14.3 (continued) Nonopioid Analgesics

Concept Review 14.4 Think about cyclooxygenase inhibitors (NSAIDs) and prostaglandins, and then describe how pain might be regulated at the nociceptor.

Headaches can be effectively treated with a variety of drug classes. Core Concept 14.7 Headaches can be effectively treated with a variety of drug classes.

Headache One of the most common complaints of patients Tension headache most common Migraine most painful type of headache is the

Headache Goals for the pharmacologic management Stop migraines in progress Prevent migraines from occurring (prophylaxis).

Drugs for Migraine Triptans Ergot Alkaloids Selective for the 5-HT1 receptor subtype Act by constricting certain vessels within the brain. Ergot Alkaloids Interact with adrenergic,dopaminergic, serotonin receptors Produce multiple actions and adverse effects.

Drugs for Migraine Other Drugs Beta-adrenergic blockers, calcium channel blockers antidepressants , and antiseizure drugs

Table 14.4 (continued) Antimigraine Drugs