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Updated 2 Feb 2023 | Antipsychotics


Tablets containing 250 micrograms benperidol

Drugs List

  • ANQUIL 250microgram tablets
  • benperidol 250microgram tablets
  • Therapeutic Indications


    For the control of deviant anti-social sexual behaviour



    250micrograms - 1.5mg per day in divided doses. Close clinical supervision is required for dose initiation and adjustment.

    Dosage should be determined giving consideration to the patient's age, severity of symptoms and previous response to other neuroleptics. Debilitated patients or those who have suffered adverse reactions to neuroleptics previously may require lower doses, with half the usual starting dose being sufficient for a therapeutic response.

    The lowest effective dose should be used.


    Half the normal starting dose may be sufficient for therapeutic response.


    Not recommended


    A lower dose may be advisable

    Patients with Renal Impairment

    Use with caution in renal failure

    Patients with Hepatic Impairment

    Use with caution in hepatic impairment


    For oral administration


    Parkinson's disease

    Extra-pyramidal disorders


    Comatose states

    Depressed states

    CNS depression

    Pregnancy (see Pregnancy section)

    Breastfeeding (see Lactation section)

    Children under 12 years


    Precautions and Warnings

    Epilepsy and conditions predisposing to epilepsy and convulsions

    Cardiovascular disease

    Renal failure

    Hepatic impairment

    Elderly or debilitation (see Dosage - Elderly)

    Adolescents (see Dosage - Adolescents )

    Myasthenia gravis

    Prostatic hypertrophy

    Susceptibility to angle-closure glaucoma

    Severe respiratory disease

    History of jaundice

    Blood dyscrasias - perform blood counts if unexplained infection or fever develops.

    Photosensitisation may occur at higher doses avoid direct sunlight.

    Some side effects may impair the ability to drive and operate machinery.

    Avoid abrupt withdrawal, as there is the possibility of acute withdrawal symptoms and relapse occurring.

    Monitor haematological parameters and liver function periodically, especially during long term therapy.

    Discontinue treatment if patients develop neuroleptic malignant syndrome.

    Consider discontinuing treatment if patients develop tardive dyskinesia. Fine vermicular movements of the tongue may be a sign of tardive dyskinesia.

    Use with caution in patients with risk factors for stroke, as an approximately 3-fold increased risk of cerebrovascular adverse events has been seen in clinical trials with some atypical antipsychotics.

    As with other neuroleptics, cases of QT interval prolongation may occur. Absence of the following risk factors should be verified before administration of benperidol:
    cardiac disease
    family history of sudden death and/or QT prolongation
    uncorrected electrolyte disturbances
    history of QT interval prolongation, ventricular arrhythmias or Torsades de Pointes.

    Consider an ECG with measurement of serum calcium, magnesium and potassium levels prior to treatment initiation, particularly in elderly patients and those with a history or family history of cardiac disease. Monitor serum electrolyte levels periodically during therapy, particularly during long-term treatment. An ECG may also be appropriate during dose escalation and when reaching the maximum therapeutic dose. Reduce dose if the QT interval is prolonged, and discontinue if it is greater than 500ms.

    Rare cases of sudden unexplained death have been reported in patients receiving antipsychotic drugs, but benperidol has not yet been clearly implicated in any case.

    The tablets contain lactose and therefore are not suitable for patients with rare hereditary problems of glucose-galactose malabsorption syndrome and lactose intolerance.

    Possible risk factors for venous thromboembolism (VTE) should be identified before and during treatment with benperidol. In patients at risk of VTE preventive measures should be taken.

    Use benperidol with caution in elderly patients with dementia, there may be a small increase in mortality.

    May potentiate effect of alcohol.

    Pregnancy and Lactation


    At the time of writing, there is insufficient information on the use of benperidol in human pregnancy to establish its safety and the manufacturer does not advise administration. Animal studies have not demonstrated teratogenic effects, but data are insufficient to exclude an increased risk of malformations. Extrapyramidal symptoms and withdrawal symptoms such as sedation, feeding problems and restlessness have been reported in the neonate after chronic maternal use of high doses near term.

    There is more data available for haloperidol than benperidol, and for this reason it is preferred. However, Schaefer concludes that use of benperidol is not an indication for termination. Detailed foetal ultrasonography, with special emphasis on the limbs, should be offered after maternal use in the first trimester. Regular psychiatric and obstetric care is recommended, in order to diagnose in time a relapse or pregnancy complications such as interuterine growth retardation or premature contractions.

    If used up to delivery, the neonate should be observed for adaption problems for at least 2 days. Neonatal adaption disorders may be prevented by reducing or discontinuing the dose of benperidol in the days immediately preceding delivery. However, the pre-pregnancy dose should then be started immediately after delivery to prevent relapse at this vulnerable stage.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Butyrophenones, including benperidol, are excreted in breast milk and therefore their use during breastfeeding is not recommended. Whilst the amounts present in milk are probably too small to be harmful, animal studies indicate possible adverse effects on the developing nervous system. The manufacturer suggests that if the use of benperidol is considered essential, breastfeeding should be discontinued.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at


    May interfere with activities requiring mental alertness. Advise patients not to drive or operate machinery until their individual susceptibility is known.

    Advise patients to avoid direct sunlight as photosensitisation may occur at higher doses.

    Advise patient that benperidol may potentiate effect of alcohol.

    Side Effects

    Extrapyramidal effects (including tremor, rigidity, hypersalivation, bradykinesia, akathisia, acute dystonia, oculogyric crisis and laryngeal dystonia)
    Tardive dyskinesia
    Neuroleptic malignant syndrome (manifested as hyperthermia, generalised muscle rigidity, autonomic instability, altered consciousness, coma and elevated CPK levels)
    Subjective feelings of mental slowness or dullness
    Liver function disturbances
    Hypersensitivity reactions
    Blood dyscrasias
    Weight changes
    Salivation changes
    Interference with temperature regulation
    Decreased appetite
    Prolongation of QT interval
    Ventricular arrhythmias
    Ventricular fibrillation
    Ventricular tachycardia
    Torsades de pointes
    Cardiac arrest
    Sudden unexplained death
    Parkinson-like symptoms
    Gastro-intestinal disturbances
    Nasal congestion
    Dry mouth
    Difficulty in micturition
    Blurred vision
    Glaucoma (closed angle)
    ECG changes
    Corneal opacities
    Lens opacities
    Purplish pigmentation of skin
    Purplish pigmentation of cornea, conjunctiva, retina
    Electrolyte disturbances
    Acid/base balance disturbance
    Pulmonary embolism
    Deep vein thrombosis (DVT)


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111)

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Shelf Life and Storage

    Protect from light

    Further Information

    Last Full Review Date: May 2011

    Reference Sources

    British National Formulary, 61st Edition (2011) Pharmaceutical Press, London.

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Summary of Product Characteristics: Anquil tablets. Concord Pharmaceuticals Ltd. Revised February 2010

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