Opioids

Question 1

Mechanism of Action

Answer 1

• Bind to specific receptors (mu, delta, and kappa) in the CNS and PNS, altering perception and response to pain
• Can act as agonists, partial agonists, antagonists, or endorphins
• This allows for varied effects and application

Question 2

Indication

Answer 2

• Managing moderate to severe acute pain
• Post surgery, injury, severe pain conditions, chronic pain management, palliative care, severe pain related to cancer, cases where other analgesics are insufficient

Question 3

Strong Full Agonists

Answer 3

• Fentanyl
• Morphine
• Hydromorphone (dilaudid)
• Methadone

Question 4

Moderate Full Agonists

Answer 4

• Oxycodone
• Tramadol

Question 5

Mild Weak or Partial Agonists

Answer 5

• Codeine

Question 6

Adverse Effects

Answer 6

• Hypotension, bradycardia
• Urinary retention
• Pruritus, tolerance and dependance, anaphylaxis

Question 7

Drug Interactions

Answer 7

• CNS depressants: Additive effects
• Anticholinergics: Additive decrease in parasympathetic activity
• Serotonergic Drugs (MAOIs, SSRIs, SNRIs): Increase serotonin with certain opioids
• CYP3A4 Inhibitors and Inducers: Altered opioid metabolism can increase or decrease drug levels
• Other opioids and mixed agonists/antagonists: Compete at opioid receptors leading to reduced receptor activation. This can lead to reduced analgesia or withdrawal

Question 8

Lab Values to Monitor

Answer 8

• Liver function: ALT, ALP, bilirubin. Since opioids are metabolized by the liver, impaired function can lead to slower metabolism, causing accumulation
• Renal function: Cr, BUN. Impaired kidney function means decreased excretion

Question 9

PCA

Answer 9

• Patient Controlled Analgesia
• Programmed with concentration, dose, lockout interval, dose limit over time period, optional continuous infusion
• Monitor pain, RR, sedation q1hx4 –> q2hx8 –> q4h for duration
• Attempted admin and given dose log is kept for each shift
• Common drugs include morphine, hydromorph, and fentanyl

Question 10

Tolerance

Answer 10

Physiological adaptation where the body requires higher doses to achieve the same effect over time

Question 11

Dependence

Answer 11

Body adapts to the drug, resulting in withdrawal symptoms if the drug is suddenly stopped

Question 12

Addiction

Answer 12

Physiological condition characterized by compulsive drug-seeking behaviour and use, despite harm