Opioid Analgesics

Question 1

What are the two categories of Opioids?

Answer 1

Opioid analgesics & Non-opioid Analgesics

Question 2

Opioid Analgesics

Answer 2

Relieve moderate-severe pain by binding to specific neuron receptors in the CNS. Commonly used after surgery, trauma, chronic musculoskeletal pain, or pain associated with advanced cancer

Controlled substance that can lead to physical dependence

Question 3

Exogenous vs Endogenous Opioids

Answer 3

Exogenous opioids are external drugs that exert their effects by binding to receptors in CNS
Endogenous opioids are created within our bodies (endorphins, enkephalins, & dynorphins) and released to control pain/inflammation at the same receptors as exogenous opioids

Question 4

Opioid Receptors

Answer 4

Mu, Kappa, & Delta
Stimulation of these receptors causes analgesia

Question 5

What are Mu receptors?

Answer 5

Located in brain & spinal cord. Most important for mediating analgesic effects. Create more significant side effects though

Question 6

Side effects of Opioids that bind to Mu receptors

Answer 6

Respiratory depression, constipation, & abuse/addiction

Question 7

Mixed Agonist-Antagonists

Answer 7

Create analgesia by binding to (activating) KAPPA receptors and blocking Mu receptors. Less likely to cause respiratory depression & abuse; less side effects and reduced risk of fatal overdose.

May produce psychotropic effects (hallucinations, vivid dreams)

Question 8

What are the main classifications of Opioids? (4)

Answer 8

1. Strong agonists
2. Mild-Moderate Agonists
3. Mixed Agonist- Antagonist
4. Antagonists

Question 9

Strong Agonists

Answer 9

Treat SEVERE pain by interacting with MU opioid receptors

Example: Morphine, Fentanyl, Meperidine, Methadone

Question 10

Mild-to-Moderate Agonists

Answer 10

Treat MODERATE pain by stimulating opioid receptors. Do NOT have as high of affinity or efficacy as strong agonist drugs.

Examples: Codeine, Hydrocodone, Oxycodone

Question 11

Antagonist Opioids

Answer 11

Do NOT produce analgesia. Block all opioid receptors with increased affinity for MU receptors

Commonly used to treat opioid overdose & addiction (reverse respiratory depression within 1-2 minutes)

Example: Naloxone

Question 12

Opioid Mechanism of Action

Answer 12

Bind to neuronal receptors (Mu, Kappa, Delta) and modify synaptic activity in the brain, spinal cord, and peripheral tissues to create analgesic effects

Question 13

Adverse Effects of Opioids

Answer 13

Sedation, mental slowing, drowsiness, euphoria, respiratory depression, GI distress
Addiction, Tolerance & Physical Dependence are at an increased risk

Question 14

Signs of Opioid Withdrawal

Answer 14

Evident 6-10 hours after last dose - Will continue for 5 days
Body aches, diarrhea, fever, goosebumps, irritability, shivering, sweating, tachycardia, N/V, weakness and fatigue

Question 15

What is Opioid Induced Hyperalgesia?

Answer 15

Failure to respond to opioids appropriately, instead experiencing increased pain (hyperalgesia) when given drug. May have genetic link

Question 16

What drug is used to treat opioid addiction?

Answer 16

Methadone (Opioid agonist)

Question 17

Rehab Implications for Opioid Use

Answer 17

Increased tolerance for activity if scheduled during peak effect
Sedation & GI discomfort may become bothersome during therapy
Monitor for S/S of respiratory depression (hypoxia & hypercapnia)
Complaints of diffuse muscle aches may be sign of addiction