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LAI Prescribing — MRCPsych Paper B MCQ

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HardSchizophrenia & PsychosisLAI PrescribingMRCPsych Paper B

A 38-year-old man with schizophrenia has responded well to oral paliperidone and wishes to switch to once-monthly paliperidone palmitate. He is not currently receiving a risperidone long-acting injection. His Cockcroft–Gault creatinine clearance is stable at 65 mL/min. Which initiation schedule is recommended?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — 100 mg on day 1 into the deltoid, then 75 mg on day 8 into the deltoid; give the first monthly maintenance dose one month later

Explanation lettering: E = shown as A · C = shown as B · D = shown as C · B = shown as D · A = shown as E

Option A is correct. A creatinine clearance of 65 mL/min constitutes mild renal impairment, for which the UK SmPC recommends reduced initiation doses of 100 mg on day 1 and 75 mg on day 8, both into the deltoid muscle. The first monthly maintenance injection is given one month after the second initiation dose; the usual maintenance dose in mild renal impairment is 50 mg monthly, adjusted within 25–100 mg. Option B is the standard initiation regimen for normal renal function. Option C uses the correct renal-adjusted doses but the initial injections must be deltoid, not gluteal. Options D and E are not licensed initiation regimens, and routine oral supplementation is unnecessary.

Reference: Electronic Medicines Compendium, Paliperidone 150 mg prolonged-release suspension for injection, Summary of Product Characteristics, section 4.2: Posology and method of administration, updated 8 May 2026. https://www.medicines.org.uk/emc/product/102151/smpc