Analgesics and Local Anaesthetics
Opioids, non-opioid analgesics, local anaesthetic pharmacology, toxicity, adjuvants and multimodal analgesia.
How to prepare for the current Primary FRCA MCQ
Build mechanisms first, practise calculations with units, connect equipment to failure modes and finish every SBA by choosing the single best answer to the exact lead-in.
Core concepts
Concept 1
Opioids, non-opioid analgesics and adjuvants act at different points in nociceptive processing and have distinct dose-limiting harms.
Exam cue: Convert concentration and volume to total local anaesthetic dose before judging safety.
Concept 2
Local anaesthetic onset, potency, duration and toxicity reflect physicochemical properties, total dose, site, tissue state and patient factors.
Exam cue: Balance mechanism-specific analgesic benefit against respiratory, renal, gastrointestinal and cardiovascular risk.
Risk pitfalls and guardrails
Comparing local anaesthetic concentrations without calculating total milligrams.
Guardrail: Convert units before substitution and reject an answer whose direction or order of magnitude is implausible.
Escalating opioid treatment without reassessing ventilation, sedation and the cause of pain.
Guardrail: Do not choose an option merely because it states a true fact; choose the one that best answers the exact lead-in under the stated conditions.
Memory anchors
How is a percentage solution converted to mg/mL?
Multiply the percentage by 10; a 1% solution contains 10 mg/mL.
Why can inflamed tissue reduce local anaesthetic effect?
Lower tissue pH reduces the unionised fraction available to cross the nerve membrane.
What is multimodal analgesia?
Using complementary interventions to improve analgesia while reducing reliance on any single drug class.
What suggests local anaesthetic systemic toxicity?
Neurological or cardiovascular disturbance temporally associated with administration, sometimes without a fixed sequence.
What is the immediate toxicity response?
Stop injection, call for help, support oxygenation and circulation, manage seizures or arrhythmia and follow the current lipid-emulsion protocol.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which receptor mediates most of morphine's analgesic and respiratory-depressant effects?
What is the principal mechanism of opioid-induced respiratory depression?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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