Use of zuclopenthixol acetate (Clopixol Acuphase)

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Key points

Zuclopenthixol acetate (Clopixol Acuphase®) is NOT quick acting and should NOT be prescribed if immediate sedation is required.

It is a potentially toxic and hazardous drug which has the potential to be used inappropriately.

There is little published data to support its use in psychiatric emergencies.

The advice and authorisation of a consultant psychiatrist must be obtained before zuclopenthixol acetate is prescribed.

Zuclopenthixol acetate must never be given to anyone who has not previously received treatment with a first generation antipsychotic.


Zuclopenthixol acetate should only be used, with extreme caution, for the treatment of acute psychosis or mania if:

1. The patient has required repeated injections of a short acting antipsychotic drug such as olanzapine or haloperidol IM, or sedative drugs such as lorazepam.

2. Giving repeated short acting antipsychotic injections would be inappropriate.

3. The patient has had a previous good response and shown good tolerability - it is best reserved for these patients.

4. Sufficient time has elapsed to assess the full response to previously injected drugs (60 mins after IM injection)

Conditions of use

The advice and authorisation of a consultant psychiatrist must be obtained before zuclopenthixol acetate is prescribed.

Prior to prescribing the patient must be seen by the prescribing doctor. Under no circumstances zuclopenthixol acetate will be administered against a verbal or faxed request. Zuclopenthixol acetate should not be prescribed as a course. The patient should be fully assessed by a doctor before each administration.

The multi-disciplinary team should consider withholding other antipsychotics for the duration of action (3 days following administration).

Never administer Never use for or in: Use in caution
  • In an attempt to "hasten" the antipsychotic effect of other antipsychotics.
  • For immediate sedation (onset of effect is too slow)
  • At the same time as other parenteral antipsychotics or benzodiazepines (may lead to over sedation which is difficult to reverse)
  • As a ‘test dose’ for Zuclopenthixol Decanoate depot
  • To a patient who is physically resistant (risk of intravasation and oil embolus).
  • Antipsychotic naïve patients
  • Pregnancy
  • Altered consciousness
  • Known sensitivity to Extra-pyramidal side-effects (EPSE) or known to suffer from EPSE
  • Parkinson's disease
  • Dementia with Lewy Bodies
  • Those accepting oral medication
  • Renal or hepatic disorders
  • Convulsive disorders
  • History of cardiovascular disorders or risk factors for QTc prolongation e.g. hypokalaemia, hypomagnesaemia
  • Dementia
  • Risk factors for stroke
  • Organic brain syndrome
Dosage and administration

For deep IM injection only into the upper outer buttock or lateral thigh.

The lowest effective dose should be used to minimise adverse reactions. The patient should be medically assessed before each administration.

Adults: The dose is 50-150mg IM (1-3mls) as a single dose, repeated if necessary after 2- 3 days. Some patients may need an additional injection between 1-2 days after the first injection. At least 24 hours must have elapsed between injections.

The duration of treatment should not exceed TWO weeks and the cumulative dose must not exceed 400mg with no more than 4 injections given in total. There is no such thing as a "course of Acuphase".

Elderly; The dose may need to be reduced due to reduced metabolism and elimination with a maximum dose of 100mg per injection.

Dose of zuclopenthixol required

Equivalent volume of zuclopenthixol acetate 50mg/ml













Duration of action

The sedative effects usually begin to be seen 2 hours after injection and peak around 36 hours (corresponding to peak serum level). The effects usually last for up to 72 hours.

NOTE - Acuphase has NO PLACE in immediate sedation as its action is NOT rapid.


Adverse reactions

These are generally dose dependent and more likely in those with no previous exposure.

Common side effects

Less common



Movement disorders

(akathisia, dystonia, Parkinsonian symptoms)

Urinary retention


Prolonged QTc interval

Raised prolactin

Neuroleptic malignant syndrome (NMS)



Consult the specific Summary of Product Characteristics for full prescribing information


Because of the extended release profile of Zuclopenthixol acetate observations should be continued for 72 hours. (See the physical health monitoring form below - Appendix 1).

Editorial Information

Last reviewed: 21 February 2020

Next review: 20 February 2023

Author(s): Drugs and Therapeutic committee

Version: 4

Approved By: Mental Health Quality & Clinical Governance Group

Reviewer Name(s): Andrew Walker, Suzanne Burke