Choosing and monitoring a first-generation antipsychotic (MEQ)

(i) Evidence position. CATIE: perphenazine (FGA) was broadly comparable in overall effectiveness to several SGAs in chronic schizophrenia (with design caveats). CUtLASS 1: no quality-of-life advantage of SGAs over FGAs in a pragmatic UK trial — so “SGA always better” is false. EUFEST: in first-episode illness, low-dose haloperidol had higher discontinuation than several SGAs — less applicable here because he is multi-episode with prior FGA response and metabolic catastrophe on olanzapine, not FEP-naive.[1][2][3]

(ii) Potency and choice. High-potency FGAs (haloperidol, fluphenazine): more EPS and prolactin, less sedation/hypotension. Low-potency (chlorpromazine): more sedation, postural hypotension, anticholinergic effects. Given prior “stiffness and restlessness” on haloperidol, either restart very low-dose high-potency with aggressive EPS plan or choose a mid-potency agent (e.g. perphenazine CATIE framing) if available, with explicit consent covering EPS, akathisia, TD (higher with FGAs per Carbon, but SGAs not zero), prolactin, and NMS rarity. Shared decision: metabolic sparing vs neurological risk.[1][4][5]

(iii) Investigations and monitoring. Baseline: FBC, U&E, LFT, fasting glucose/lipids, weight/BMI, pregnancy test if relevant; ECG if cardiac risk or high-risk dosing. Early visits: examine for dystonia, parkinsonism, akathisia (Barnes language). Chronic: serial AIMS for TD, symptom-directed prolactin, adherence, metabolic co-care for diabetes.[4][6]

(iv) Emergencies. Acute dystonia: parenteral anticholinergic (local product), airway care if laryngeal, then reduce/switch FGA. Severe akathisia: do not escalate antipsychotic; reduce dose or switch; treat restlessness (e.g. beta-blocker options per local practice).[6]

(v) Depot vs TRS path. Depot (e.g. flupentixol/zuclopenthixol/haloperidol decanoate per formulary) after oral tolerability of same agent, if adherence is the barrier — real-world depot data support LAI strategies for relapse prevention at population level. If he has already had two adequate failed trials with adherence confirmed and remains ill, apply TRRIP: assess treatment resistance and offer clozapine rather than endless FGA cycling or depot-as-delay.[7][8]