PSA Pain Management 2 — Questions and Answers
Question 1: A patient on long-term oral morphine develops refractory constipation. Which laxative class is most appropriate?
- Bulk-forming (psyllium)
- Stimulant (senna) (Correct answer)
- Stool softener (docusate)
- Osmotic (lactulose) alone
Correct answer: Stimulant (senna)
Stimulant laxatives such as senna are first-line for opioid-induced constipation because they directly stimulate colonic motility.
Question 2: A patient with eGFR 15 ml/min requires opioid analgesia for cancer pain. Which opioid is most appropriate?
- Morphine
- Codeine
- Fentanyl (Correct answer)
- Tramadol
Correct answer: Fentanyl
Fentanyl is preferred in severe renal impairment because its metabolites are not renally excreted and do not accumulate to cause toxicity.
Question 3: An adult weighing 48 kg is prescribed paracetamol for post-operative pain. What is the maximum safe single dose?
- 1000 mg
- 750 mg
- 500 mg
- 720 mg (Correct answer)
Correct answer: 720 mg
For patients weighing less than 50 kg, the maximum single dose of paracetamol is 15 mg/kg, giving 720 mg for a 48 kg adult.
Question 4: Which drug combination carries the highest risk of serotonin syndrome?
- Tramadol + amitriptyline (Correct answer)
- Morphine + diazepam
- Codeine + paracetamol
- Ibuprofen + codeine
Correct answer: Tramadol + amitriptyline
Tramadol inhibits serotonin reuptake, and combined with amitriptyline (which also has serotonergic activity), the risk of serotonin syndrome is significantly increased.
Question 5: A patient is prescribed MST Continus 30 mg twice daily. What is the correct breakthrough (PRN) morphine dose?
- 5 mg
- 10 mg (Correct answer)
- 30 mg
- 60 mg
Correct answer: 10 mg
The PRN breakthrough dose should be one-sixth of the total daily opioid dose; 60 mg/day divided by 6 equals 10 mg.
Question 6: A patient stabilised on warfarin requires analgesia for headache. Which analgesic should be avoided?
- Paracetamol 500 mg
- Codeine 30 mg
- Aspirin 600 mg (Correct answer)
- Gabapentin 100 mg
Correct answer: Aspirin 600 mg
Aspirin inhibits platelet aggregation and can displace warfarin from protein binding, significantly increasing bleeding risk.
Question 7: A post-operative patient on morphine infusion has a respiratory rate of 7 breaths/min. What is the most appropriate immediate action?
- Administer flumazenil 200 mcg IV
- Administer naloxone 400 mcg IV bolus
- Titrate naloxone 40–100 mcg IV every 2 minutes (Correct answer)
- Administer adrenaline 1 mg IV
Correct answer: Titrate naloxone 40–100 mcg IV every 2 minutes
Naloxone should be titrated in small incremental doses to reverse respiratory depression while avoiding precipitating acute withdrawal and severe pain.
PSA Pain Management 2
A patient on long-term oral morphine develops refractory constipation.
Which laxative class is most appropriate?