Opioids, Non-Opioid Analgesics, and Multimodal Antinociception — WACS Viva & Clinical Scenarios (Pharmacology and Applied Pharmacology)

Exam-style opioids, non-opioid analgesics, and multimodal antinociception viva scenarios with examiner probes and model answers for ANAESTHESIA candidates.

Scenarios covered

• SCENARIO 1: A 62-year-old male with mild renal impairment (serum creatinine 160 micromol/L) underwent open colorectal surgery. He is prescribed postoperative pethidine 100 mg intramuscularly every 4 hours. On postoperative day 2, he develops confusion, tremulousness, and generalized twitches. Explain the pharmacological basis of this condition and formulate an alternative analgesic regimen.
• SCENARIO 2: A 30-year-old opioid-naive female who received 20 mg of intravenous morphine during a complex exploratory laparotomy arrives in the recovery room with a respiratory rate of 6 breaths per minute, pin-point pupils, and SpO2 of 88% on room air. Outline your step-by-step pharmacological management.
• SCENARIO 3: A 45-year-old male undergoes open inguinal hernia repair under general anaesthesia. Design an evidence-based multimodal analgesic regimen incorporating paracetamol, NSAIDs, and low-dose ketamine, detailing receptor targets and organ safety precautions.
• SCENARIO 4: Contrast the pharmacokinetics, metabolism, context-sensitive half-time, and clinical utility of Remifentanil versus Fentanyl during neurosurgical procedures.