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First-generation antipsychotic (phenothiazine) Pregnancy: SPC §4.6, verbatim: 'Available data from studies in animals have shown no evidence of a teratogenic effect. Available human data are insufficient to exclude a risk of congenital malformation in children exposed in utero... As a precautionary measure, the use of periciazine should be avoided during pregnancy unless the potential benefits outweigh the potential risks. If possible, it is preferable to taper the dosage of both neuroleptics and antiparkinsonians, which potentiate the atropine-like effects of neuroleptics, at the end of pregnancy. A period of monitoring of the neurological and gastro-intestinal functions of the neonate appears warranted... It may occasionally prolong labour and at such a time should be withheld until the cervix is dilated 3-4 cm. Possible adverse effects on the foetus include lethargy or paradoxical hyperexcitability, tremor and low Apgar score.' Third-trimester phenothiazine exposure has been reported to cause respiratory disorders from tachypnoea to respiratory distress, bradycardia and hypotonia; atropinic effects such as meconium ileus, delayed meconium passage, initial feeding difficulties, abdominal bloating and tachycardia; and neurological disorders including extrapyramidal symptoms, somnolence and agitation. Lactation: 'In the absence of data on excretion in breast milk, breastfeeding is not recommended during treatment.'

Pericyazine

Brand names: Neulactil

Pericyazine is a phenothiazine (piperidine subgroup) first-generation antipsychotic, used in the management of psychosis and as an adjunct in severe anxiety or agitation.

Adult dose

Dose: SEVERE CONDITIONS (the SPC's 'Indication (a)') - Adults: 'Initially 75 mg per day in divided doses. Dosage should be increased by 25 mg per day at weekly intervals until the optimum effect is achieved.' Elderly: 'Initially 15-30 mg per day in divided doses. If this is well tolerated the dosage may be increased if necessary for optimum control of behaviour.' || MILD OR MODERATE CONDITIONS (the SPC's 'Indication (b)') - Adults: 'Initially 15-30 mg daily, divided into two portions with a larger dose being given in the evening.' Elderly: '5-10 mg per day is suggested as a starting dose. It may be divided so that a larger portion is given in the evening.' For both tiers, 'Half or quarter the normal adult dose may be sufficient for maintenance therapy.'
Route: Oral - SPC §4.2, verbatim: 'Route of administration: oral.' Tablets; the fetched product is the 10 mg tablet strength. This is this page's only route, so the scope above is complete for route.
Frequency: In divided doses. For the mild/moderate regimen the SPC specifies 'divided into two portions with a larger dose being given in the evening'; for the elderly on that regimen, 'It may be divided so that a larger portion is given in the evening.' No fixed number of daily doses is given for the severe-conditions regimen beyond 'in divided doses'.
Max: 300 mg per day, and only for the severe-conditions regimen ('Indication (a)') - SPC §4.2, verbatim: 'Maintenance therapy would not normally be expected to exceed 300 mg per day.' No ceiling is stated for the mild or moderate regimen ('Indication (b)'), and none is stated for elderly patients on either regimen.
INDICATION SCOPE - IMPORTANT: the fetched SPC §4.2 labels its two dose tiers only by severity, as 'Severe conditions Indication (a)' and 'Mild or moderate conditions Indication (b)'. §4.1, which names those indications, was NOT fetched, so the figures above are reproduced with the SPC's own severity labels and are deliberately not attached here to a named diagnosis. They do match, number for number, the two regimens already on this page (75 mg/day initially with a 300 mg/day maintenance cap, and 15-30 mg/day for the milder tier), which is this page's primary use - pericyazine as an oral first-generation phenothiazine antipsychotic - so the primary indication is covered even though the source does not spell the indication names out. || TITRATION (§4.2): 'Dosage requirement varies with the individual and the severity of the condition being treated. Initial dosage should be low with progressive increases until the desired response is obtained, after which dosage should be adjusted to maintain control of the symptoms.' || WITHDRAWAL (§4.4): 'Acute withdrawal symptoms, including nausea, vomiting and insomnia, have very rarely been reported following the abrupt cessation of high doses of neuroleptics. Relapse may also occur, and the emergence of extrapyramidal reactions has been reported. Therefore, gradual withdrawal is advisable.' Also: 'In schizophrenia, the response to neuroleptic treatment may be delayed. If treatment is withdrawn, the recurrence of symptoms may not become apparent for some time.' || PAEDIATRICS: paedDose is null because §4.2 states 'Pericyazine tablets are not recommended for children', and §4.3 contraindicates use in children under 1 year. || SEIZURES (§4.4): 'The occurrence of convulsive seizures necessitates the discontinuation of treatment.' || The §4.4 text was truncated at the source-fetch limit part-way through the QT-prolongation paragraph, so treat the warnings captured here as incomplete.

Dose adjustments

Renal

No dose adjustment is given; the SPC's position is avoidance. §4.4, verbatim: 'Neuroleptics should be avoided in patients with liver or renal dysfunction, Parkinson's disease, hypothyroidism, cardiac failure, phaeochromocytoma, myasthenia gravis, prostrate hypertrophy.' No creatinine-clearance thresholds and no reduced doses appear anywhere in the fetched text.

Hepatic

No dose adjustment is given; the same §4.4 sentence directs that neuroleptics 'should be avoided in patients with liver or renal dysfunction'. §4.8 adds a stopping rule rather than a dose rule: jaundice 'occurs in a very small percentage of patients taking neuroleptics. A premonitory sign may be a sudden onset of fever after one to three weeks of treatment followed by the development of jaundice... Treatment should be withheld on the development of jaundice.'

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Known hypersensitivity to pericyazine or to any of the other ingredients (SPC §4.3)
  • Risk of urinary retention due to urethroprostatic disorders (SPC §4.3)
  • Risk of angle-closure glaucoma (SPC §4.3)
  • History of agranulocytosis (SPC §4.3)
  • Concurrent dopaminergic antiparkinsonism agents (SPC §4.3)
  • Children younger than 1 year - 'due to a possible link between use of phenothiazine-containing products and Sudden Infant Death Syndrome (SIDS)' (SPC §4.3)
  • Hypersensitivity or intolerance to gluten, because the medicinal product contains wheat starch (gluten) (SPC §4.3)
  • Pregnancy is cross-referenced from §4.3 ('See use in pregnancy below'); §4.6 stops short of an absolute bar - 'the use of periciazine should be avoided during pregnancy unless the potential benefits outweigh the potential risks'
  • Not contraindications but §4.4 avoidance: liver or renal dysfunction, Parkinson's disease, hypothyroidism, cardiac failure, phaeochromocytoma, myasthenia gravis, prostatic hypertrophy, known phenothiazine hypersensitivity, and a history of narrow angle glaucoma or agranulocytosis; caution in the elderly, 'particularly during very hot or very cold weather (risk of hyper-hypothermia)', and close monitoring in epilepsy or a history of seizures

Side effects

  • Cardiovascular (§4.8): 'hypotension, usually postural, commonly occurs. Elderly or volume depleted subjects are particularly susceptible'
  • ECG changes including QT prolongation, ST depression, U-wave and T-wave changes (§4.8)
  • Cardiac arrhythmias, including ventricular and atrial arrhythmias, a-v block and ventricular tachycardia 'which may result in ventricular fibrillation or cardiac arrest... possibly related to dosage'; predisposing factors are pre-existing cardiac disease, old age, hypokalaemia and concurrent tricyclic antidepressants (§4.8)
  • Isolated reports of sudden death, including possible cases of cardiac origin and cases of unexplained sudden death (§4.8)
  • Torsade de pointes risk - 'Neuroleptic phenothiazines may potentiate QT interval prolongation which increases the risk of onset of serious ventricular arrhythmias of the torsade de pointes type, which is potentially fatal (sudden death)', exacerbated by bradycardia, hypokalaemia and congenital or drug-induced QT prolongation (§4.4)
  • Hepatic: jaundice with the biochemical characteristics of obstructive (cholestatic) jaundice, often preceded by a sudden fever after one to three weeks; liver injury reported very rarely (§4.8)
  • Haematological: 'A mild leukopenia occurs in up to 30% of patients on prolonged high dosage of neuroleptics; agranulocytosis may occur rarely; it is not dose-related' (§4.8)
  • Respiratory depression is possible in susceptible patients (§4.8)
  • Sedation or somnolence, 'more marked at the beginning of treatment' (§4.8)
  • Neuroleptic malignant syndrome - pallor, hyperthermia, autonomic dysfunction, altered consciousness, muscle rigidity, sometimes preceded by sweating and arterial instability (§4.4/§4.8)
  • Anticholinergic effects: dry mouth, constipation, paralytic ileus, accommodation disorders, risk of urinary retention (§4.8)
  • Extrapyramidal: acute dystonias or dyskinesias, 'usually transitory... commoner in children and young adults, and usually occur within the first four days of treatment or after dosage increases'; akathisia 'characteristically occurs after large initial doses'; parkinsonism 'commoner in adults and the elderly... usually develops after weeks or months of treatment'; tardive dyskinesia (§4.8, text truncated at the source-fetch limit)
  • Lowered seizure threshold - phenothiazines may provoke convulsive seizures (§4.4)

Monitoring

  • Full blood count regularly - 'As agranulocytosis may occur rarely, regular monitoring of the complete blood count is recommended' (§4.4)
  • Urgent blood count on any unexplained fever, sore throat or infection - 'All patients should be informed that, should fever, sore throat or another infection occur, the consulting physician must be notified immediately and the blood count monitored. If there is a marked change in the latter (hyperleucocytosis, granulopenia), administration... should be stopped' (§4.4)
  • Stop treatment on unexplained fever - 'It is imperative that treatment be discontinued in the event of unexplained fever, as this may be a sign of neuroleptic malignant syndrome' (§4.4)
  • ECG and biochemistry before starting - 'If the clinical situation permits, medical and laboratory evaluations (e.g. biochemical status and ECG) should be performed to rule out possible risk factors (e.g. cardiac disease; family history of QT prolongation; metabolic abnormalities such as hypokalaemia, hypocalcaemia...)' (§4.4)
  • Liver function / jaundice - 'Treatment should be withheld on the development of jaundice' (§4.8)
  • Seizure activity - 'Close monitoring is required in patients with epilepsy or a history of seizures'; discontinue if convulsive seizures occur (§4.4)
  • Blood pressure, given that postural hypotension commonly occurs and the elderly and volume-depleted are most susceptible (§4.8)
  • Temperature regulation in the elderly during very hot or very cold weather (§4.4)
  • Neonate of a treated mother - 'A period of monitoring of the neurological and gastro-intestinal functions of the neonate appears warranted' and 'newborns should be monitored carefully' (§4.6)

Clinical monograph

How it works

It antagonises central dopamine D2 receptors, which underlies its antipsychotic effect; marked antagonism at muscarinic, histamine H1 and alpha-adrenergic receptors accounts for its sedative and autonomic effects.

Prescribing in practice

  • Pronounced sedation and postural hypotension can occur, particularly in elderly or debilitated patients, who are also at increased risk of extrapyramidal effects and falls.
  • Like other antipsychotics it carries a risk of QT-interval prolongation and of neuroleptic malignant syndrome.
  • Marked antimuscarinic activity may cause dry mouth, blurred vision, constipation and urinary retention, and it should be used with caution in cardiovascular disease and epilepsy.

Monitoring

Monitor for extrapyramidal symptoms, sedation, postural blood pressure and emergent features of neuroleptic malignant syndrome, with metabolic and ECG review where indicated.

Counselling the patient

  • This medicine can make you drowsy, so avoid driving or operating machinery until you know how it affects you.
  • Stand up slowly to reduce dizziness, and report any high fever, muscle stiffness or confusion urgently.
  • Avoid alcohol while taking this medicine as it adds to drowsiness.

Evidence & guidelines

Use of first-generation antipsychotics such as pericyazine is informed by long-standing clinical experience and NICE guidance on antipsychotic prescribing.

Reference: NICE CG178; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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