California Rocket Fuel — MRCPsych Paper B MCQ
Instant feedback + full explanation. One question, done properly.
Educational content. Not a substitute for clinical judgement or local policy.
Reveal the answer and explanation
Correct answer: E — Venlafaxine inhibits SERT and NET, while mirtazapine blocks alpha-2 and 5-HT2/5-HT3 receptors, favouring noradrenergic and 5-HT1-mediated transmission
Explanation lettering: E = shown as A · D = shown as B · A = shown as D · B = shown as E
“California rocket fuel” specifically refers to venlafaxine plus mirtazapine, not to an SSRI–mirtazapine combination generally. Venlafaxine inhibits serotonin and noradrenaline reuptake. Mirtazapine blocks presynaptic alpha-2 auto- and heteroreceptors, increasing noradrenergic and serotonergic transmission, while 5-HT2 and 5-HT3 antagonism preferentially directs serotonergic signalling through 5-HT1 receptors. This provides complementary rather than identical pharmacology, making B correct. Mirtazapine is not a direct 5-HT1A agonist, reuptake inhibitor or MAO inhibitor, excluding A and C–E. The complementary mechanism is a pharmacological rationale, not proof of superior clinical efficacy: NICE places antidepressant combinations within specialist further-line care because of the increased adverse-effect burden.
Reference: Electronic Medicines Compendium. Venlafaxine XL 75 mg Prolonged-release Hard Capsules SmPC, section 5.1, revised 2024, https://www.medicines.org.uk/emc/product/15058/smpc; and Mirtazapine 30 mg tablets SmPC, section 5.1, revised 2025, https://www.medicines.org.uk/emc/product/100083/smpc