Anti-Inflammatory and Analgesics Flashcards
Narcotic Analgesics
Used in treating moderate to severe pain
Most effective drugs for pain management
Drugs
Opiate agonists, mixed agonist-antagonists, and antagonists
Activity at three sites of brain: mu, kappa, and delta
Opioid Receptors
Four opioid receptors: delta (δ), mu (μ), sigma (σ), kappa (κ)
Stimulation of sigma results in hallucinations
Stimulation of mu (μ) and kappa (κ) and possibly delta (δ) results in analgesia
Adjuvants
Often added to opioids to assist in relieving pain and reduce some of the adverse effects of the narcotics
Antidepressants, antiepileptic’s (can be used for chronic neuropathic pain), antiemetic’s (to combat nausea/vomiting), sedatives, corticosteroids
What are Opioid Analgesics?
Agonist – binds to an opioid receptor in the brain and causes an analgesic response
Partial Agonist – binds to a pain receptor but causes a weaker neurologic response than a full agonist
Mixed Agonist-Antagonist – agonist effects at some opioid receptors and weak antagonist effects at other receptors. Can be used for chronic pain management, less of a risk of respiratory stress/addiction
Chemical Classification of Opioids
Meperidine-like drugs:
Meperidine, fentanyl, remifentanil, sufentanil, alfentanil
Methadone-like drugs:
Methadone, Propoxyphene
Morphine-like drugs:
Morphine, Heroin, Hydromorphone, Oxymorphone, Codeine, Hydrocodone, Oxycodone
Other: Tramadol
Indications for use of Opioids
Morphine-like opioids are often used to control postoperative pain and other types of pain.
These are usually first-line analgesics due to the fact that some are readily available in injectable form.
Opioids also suppress the medullary cough center, which results in cough suppression
Always assess O2 Stat, Respiratory rate from heavy opioid effects. Check gag/cough reflex, as a result of CNS depression.
Opioids are used especially as a chest surgery medication to prevent coughing/opening of wound
Morphine
Treatment of moderate to severe acute or chronic pain
Dyspnea with acute left ventricular failure and pulmonary edema (vasodilating effect, lowers afterload to help heart)
Pain of MI: MONA (morphine, oxygen, nitroglycerin, aspirin)
Agonist at mu, kappa, and possibly delta opiate receptors
Reduction in release of neurotransmitters in presynaptic space
Decrease in the release of substance P
Alters release of pain responsive neurons
Morphine (Primary and Adverse Effects)
Vasodilator: Could be adverse (hypotensive patient) Elevates intracranial pressure Stimulates mainly the mu (U) receptor Depresses respiratory function Constipation (Adverse) Causes urinary retention (adverse) Lowers blood pressure Bradycardia Constricts the pupils (miosis). NORMAL RESPONSE. Check symmetry Vomiting
Morphine Contraindications/Precautions
Contraindications
Hypersensitivity, pre-existing respiratory depression, acute or severe bronchial asthma, and upper airway obstruction
Premature neonates and labor and delivery where premature neonate is anticipated
Heart failure from lung disease, cardiac arrhythmias, increased intracranial pressure, head injury, brain tumor, acute alcoholism, or delirium tremens
Precautions
Patients receiving other CNS depressants, those who are old or debilitated or have renal or hepatic impairment
Morphine Adverse Effects
Excessive CNS depression: respiratory depression,
hypoventilation, apnea, respiratory arrest, circulatory
depression, cardiac arrest, shock, and coma
Most frequent effects: respiratory depression, apnea,
bradycardia, light-headedness, dizziness, sedation, nausea and vomiting, sweating
Drug Interactions:
CNS depressants, anti-depressants, H2 blockers
Barbiturate anesthetics
Morphine Therapeutics Effects
Assessing pain using pain assessment tools
Location, intensity, quality, and character
Providing analgesia
Administering before level of pain gets severe; around the clock or continual administration
Titrating dose based on patient’s response
Minimizing Adverse Effects
Performing frequent and astute assessment
Using patient-controlled analgesia (PCA)
Toxicity and Management of
Opioid Analgesic Overdose
Opioid antagonist (ex. Narcan, ReVia, Revex) will reverse not only respiratory suppression but will also reverse the pain control
The nurse must be cautious of adverse effects of reversal medications. Ex. HTN, arrhythmias, pulmonary edema, withdrawal, nervousness, headache, N/V
Naloxone (Narcan)
Naloxone (Narcan)
Narcotic antagonist used to reverse the effects of opiates (respiratory depression) or overdose
Competes for opiate receptor sites
Adults, children, and neonates
Administration IM, SC (sub-q), or IV; most rapid onset via IV administration (2 minutes)
Careful monitoring of the patient necessary – shorter duration of action than opioids
Repeated doses may be necessary
N/V, sweating, tachycardia, ↑BP, tremors. Cardiac dysrhythmia can occur from rapid reversal
The half life of the reversal agent is much shorter than the narcotic/opioid analgesic
hydromorphone (Dilaudid)
Semi-synthetic opium analogue
Actions: almost identical to morphine
Indications: same as MSO4
1-1.5mg of hydromorphone = 10mg MSO4
More potent than morphine, use small doses
Less respiratory depression (it does cause it) & physical dependence
Can cause transient hyperglycemia
meperidine (Demerol)
Synthetic opioid
Action: same as MSO4…binds to receptors in CNS
Indications: treat pain pre- & post-op, support anesthesia, during labor
Pharmacokinetics:
less potent than MSO4
Longer half-life
Accumulation of active metabolite- normeperidine:
15-30 hr ½ life. CNS toxin, can cause tremors, seizures, & changes in LOC. Worse if renal impairment.
Interaction w/ antiepileptic hydantoins- ↓effect of meperidine
fentanyl (Sublimaze, Duragesic)
Actions: very potent analgesic 100:1 over MSO4 (0.1mg = 10 mg MSO4)
Indications: severe pain, chronic pain (patches w/ 72 hr duration), adjunct to general anesthetics, epidural PCA (off-label). Contraindicated in opioid naïve pts.
Pharmacokinetics:
transdermal- 24 hr to achieve effect.
Fewer respiratory and emetic effects than morphine
Drugs that inhibit cytochrome P-450 3A4 will ↑↑plasma concentrations of Fentanyl
methadone (Methadose, Dolophine)
Actions: like MSO4
Indications: pain, prevention of withdrawal symptoms from heroin, maintenance tx for narcotic abuse.
Pharmacokinetics: longer ½ life (15-30 hrs vs. 1.5-2hrs)
High abuse potential
Codeine
Treatment of mild to moderate pain and cough suppression
Available in oral tablets and injectable form; combined with acetaminophen
Antitussive properties
Similar action to morphine but milder
Action at specific opioid receptors in CNS
Direct action on medullary cough center; drying effect on mucous membranes
Codeine Precautions
Patients who need cough to maintain airway and those with asthma and emphysema
Patients with preexisting cardiac disease
Pregnant and lactating women
Hypersensitivity and history of narcotic addiction
Patients needing to be alert or drive and those with suspected head injury or have had a craniotomy
