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First-generation antipsychotic (butyrophenone) Pregnancy: Safety in pregnancy has not been established, although animal studies have not demonstrated teratogenic effects; as with other drugs it is not advisable to administer benperidol in pregnancy. Neonates exposed to antipsychotics during the third trimester are at risk of adverse reactions including extrapyramidal and/or withdrawal symptoms of varying severity and duration following delivery — agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress or feeding disorder have been reported — so newborns should be monitored carefully. Butyrophenones are excreted in breast milk and are not recommended during lactation; if use is considered essential, breast feeding should be discontinued.

Benperidol

Brand names: Anquil

Benperidol is a butyrophenone first-generation antipsychotic that has been used to control deviant antisocial sexual behaviour.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Adults: 0.25-1.5 mg daily in divided doses. This is the only adult regimen given in the Anquil (benperidol) SPC section 4.2, which states a single dose range and does not sub-divide it by indication.
Route: Oral
Frequency: Daily total given in divided doses. Dosage is best initiated and adjusted under close clinical supervision, as individual response to neuroleptic drugs is variable.
Max: 1.5 mg/day
In determining dosage, consideration should be given to the patient's age, the severity of symptoms and previous response to other neuroleptic drugs. Patients who are debilitated, or those with previously reported adverse reactions to neuroleptic drugs, may require less, and half the normal starting dose may be sufficient for therapeutic response. Elderly: half the normal starting dose may be sufficient for therapeutic response. In adolescents, a lower dose may be advisable. Paediatric population: not recommended (see paedDose). As with all medications the lowest effective dose should be used, and the SPC adds that benperidol should be given in the minimal effective dose for the minimum possible time because of the risk of tardive dyskinesia. Withdrawal: acute withdrawal symptoms including nausea, vomiting and insomnia have very rarely been described after abrupt cessation of high doses of antipsychotic drugs, and relapse may occur — gradual withdrawal is advisable. Caution is advised in patients with liver disease, renal failure, cardiovascular disease, epilepsy and conditions predisposing to epilepsy and convulsions. Concomitant neuroleptics should be avoided. This medicine contains lactose: patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take it. An approximately 3-fold increased risk of cerebrovascular adverse events has been seen in randomised placebo-controlled trials in the dementia population with some atypical antipsychotics; an increased risk cannot be excluded for other antipsychotics or other patient populations, and benperidol should be used with caution in patients with risk factors for stroke. SOURCE COMPLETENESS: section 4.2 was retrieved in full, but sections 4.4 and 4.8 of this bundle end at the source-fetch limit, so the warnings, monitoring and adverse-effect entries below are partial and are not a complete account of the label; no interaction section was retrieved at all.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients listed in section 6.1
  • Hypersensitivity to other butyrophenones
  • Comatose states
  • Patients with extrapyramidal symptoms
  • Patients with CNS depression
  • Patients with depressive disorders
  • Patients with Parkinson's disease

Side effects

  • Rare: neuroleptic malignant syndrome, depression, seizures, confusional state, agitation
  • Frequency not known — nervous system: sweating, dizziness, headache, extrapyramidal disorder, tremor, muscle rigidity, bradykinesia, akathisia, dystonia, oculogyric crisis, spasmodic dystonia, tardive dyskinesia, autonomic nervous system imbalance, altered state of consciousness, coma, mental impairment, insomnia
  • Frequency not known — blood: blood disorder and granulocytopenia; blood dyscrasias including granulocytopenia
  • Frequency not known — endocrine: hyperprolactinaemia, which may cause galactorrhoea, gynaecomastia and oligomenorrhoea or amenorrhoea
  • Frequency not known — immune: hypersensitivity, reported as oedema, skin rashes or hypersensitivity reactions such as exanthema and pruritus
  • Frequency not known — metabolism: weight fluctuation
  • Extrapyramidal symptoms may occur as with all neuroleptics (tremor, muscle rigidity, hypersalivation, bradykinesia, akathisia, acute dystonia, oculogyric crisis, laryngeal dystonia); anti-Parkinson agents should only be given as required and not prescribed routinely as a preventive measure
  • Tardive dyskinesia may appear on long-term therapy or after drug discontinuation, mainly as rhythmical involuntary movements of the tongue, face, mouth or jaw, and may be permanent in some patients; it can be precipitated or aggravated by anti-Parkinson drugs and may occur after abrupt withdrawal
  • QT interval prolongation may occur, as with other neuroleptics
  • Venous thromboembolism has been reported with antipsychotic drugs
  • Rare cases of sudden and unexplained death have been reported in psychiatric patients receiving antipsychotic drugs, although this product has not been clearly implicated in any case
  • The adverse-effect section of this source ends at the source-fetch limit, so this list is not the complete label list

Monitoring

  • Where prolonged treatment is envisaged, it is a reasonable precaution to carry out regular blood counts and tests of liver function
  • Before starting treatment, verify the absence of risk factors for arrhythmia if the clinical situation permits: cardiac disease, a family history of sudden death and/or QT prolongation, uncorrected electrolyte disturbances, and a history of QT interval prolongation, ventricular arrhythmias or Torsades de Pointes
  • Consider an ECG with measurement of serum calcium, magnesium and potassium before initiating treatment, especially in the elderly and in patients with a personal or family history of cardiac disease or abnormal findings on cardiac examination
  • Monitor serum electrolytes periodically during therapy and correct if necessary, especially during long-term use, if concomitant diuretics are taken, or during intercurrent illness
  • Consider an ECG to assess the QT interval whenever dose escalation is proposed and when the maximum therapeutic dose is reached
  • Reduce the dose if the QT interval is prolonged, and discontinue if the QTc interval is greater than 500 ms
  • Identify all possible risk factors for venous thromboembolism before and during treatment and undertake preventive measures

Clinical monograph

How it works

It is a potent dopamine D2 receptor antagonist, blocking dopaminergic neurotransmission in the central nervous system.

Prescribing in practice

  • As a high-potency typical antipsychotic it carries a high risk of extrapyramidal side effects, including acute dystonia and tardive dyskinesia, and rarely neuroleptic malignant syndrome.
  • It can prolong the QT interval; caution is needed with other QT-prolonging drugs and in cardiac disease.
  • Use cautiously in the elderly, in Parkinson's disease and in those with epilepsy.

Monitoring

Monitor for extrapyramidal symptoms and, where relevant, ECG and prolactin, alongside response.

Counselling the patient

  • Report any abnormal movements, muscle stiffness or restlessness.
  • Avoid alcohol, which increases drowsiness.
  • Take as directed and do not stop abruptly without advice.

Evidence & guidelines

Use is based on the SPC and established clinical experience rather than large modern trials.

Reference: RCPsych prescribing guideline; 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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