Antipsychotic depot injections (Formulary: CNS)

TAM (Treatments and Medicines) NHS Highland
NHS Highland

Long-acting depot injections are used for the patient’s convenience or to improve compliance. They may produce more extrapyramidal reactions than oral preparations. For traditional depot preparations (flupentixol, fluphenazine, haloperidol and zuclopenthixol decanoate) the BNF recommends giving a test dose as some side-effects are prolonged. The drug is dissolved in oil and, when injected into muscle, it slowly comes out of the oil and into the bloodstream over a period of up to 6 weeks. Peak levels are achieved within 10 days. Steady blood levels are achieved by 6 to 12 weeks, depending on which drug is used.

ARIPIPRAZOLE

Therapy notes

MHRA advice: Aripiprazole (Abilify and generic brands): risk of pathological gambling (December 2023) (www.gov.uk).

  • Note: Aripiprazole: a trial of oral aripiprazole is recommended before initiation of aripiprazole depot injection because no test dose is given.

Formulation and dosage details

Formulation:

Powder and solvent for prolonged-release suspension for injection vial (Abilify Maintena®) 400mg, pre-filled syringe 400mg (s)

Dosage:

By deep intramuscular injection into the gluteal muscle, 400mg repeated at monthly intervals (minimum 26 days between injections). Continue treatment with 10 to 20mg of oral aripiprazole for 14 consecutive days after the first injection. For dose adjustments due to side- effects, concomitant use of interacting drugs or missed depot doses, consult SPC.

FLUPENTIXOL DECANOATE

Therapy notes

Formulation and dosage details

Formulation:

Solution for injection (oily) 20mg/mL, 40mg/2mL,100mg/mL, 200mg/mL

Dosage:

By deep intramuscular injection into the upper outer buttock or lateral thigh, test dose 20mg, then after at least 7 days 20 to 40mg repeated at intervals of 2 to 4 weeks, adjusted according to response; maximum 400mg weekly; usual maintenance dose 50mg every 4 weeks to 300mg every 2 weeks. Older people, initially quarter to half adult dose.

HALOPERIDOL DECANOATE

Therapy notes

  • Note: If fortnightly administration of haloperidol decanoate is preferred, halve the dose.

Formulation and dosage details

Formulation:

Solution for injection (oily) 50mg/mL, 100mg/mL

Dosage:

By deep intramuscular injection into the gluteal muscle, initially 50mg every 4 weeks, if necessary increasing by 50mg increments to 300mg every 4 weeks; higher doses may be needed in some patients. Older people, initially 12·5 to 25mg every 4 weeks.

PALIPERIDONE

Therapy notes

MHRA advice: Risperidone and paliperidone: risk of intraoperative floppy iris syndrome in patients undergoing cataract surgery (December 2014) (www.gov.uk)

Formulation and dosage details

Formulation:

Suspension for injection, pre-filled syringe (Xeplion®) 50mg, 75mg, 100mg, 150mg (s)

Dosage:

By deep intramuscular injection into the deltoid muscle, 150mg on day 1, then 100mg on day 8, then adjusted at monthly intervals according to response; recommended maintenance dose 75mg (range 25 to 150mg) monthly.

Formulation and dosage details

Formulation:

Prolonged-release suspension for injection, pre-filled syringe (Trevicta®) 175mg, 263mg, 350mg, 525mg (s)

Dosage:

By deep intramuscular injection into the deltoid muscle,
for 3-monthly maintenance treatment in patients who are clinically stable on 1-monthly paliperidone injection; refer to SPC.

As per SMC 1181/16: paliperidone palmitate (Trevicta®), a three-monthly injection, is indicated for the maintenance treatment of schizophrenia in adult patients who are clinically stable on one-monthly paliperidone palmitate injectable product. 

RISPERIDONE

Therapy notes

MHRA advice: Drug-name confusion: reminder to be vigilant for potential errors (January 2018) (www.gov.uk)
MHRA advice: Risperidone and paliperidone: risk of intraoperative floppy iris syndrome in patients undergoing cataract surgery (December 2014) (www.gov.uk)

  • Note: Risperidone depot injection differs from other depot formulations.
  • A trial of oral risperidone is recommended before initiation of risperidone depot injection because no test dose is given.
  • During initiation there is a lag time of 3 weeks before significant blood levels are reached; continue oral risperidone if necessary for a minimum of 4 to 6 weeks (often longer); oral risperidone may be continued during dose adjustment of the depot injection.
  • Peak levels are reached 4 to 6 weeks after depot injection and steady state blood levels by 8 to 10 weeks.
  • Store the injection in a fridge (only stable for 7 days if unrefrigerated).
  • The whole vial must be administered (due to the nature of the suspension) giving limited flexibility in dosing.

Formulation and dosage details

Formulation:

Powder and solvent for suspension for injection (Risperdal Consta®)  25mg, 37·5mg, 50mg

Dosage:

By deep intramuscular injection into the deltoid or gluteal muscle, patients taking oral risperidone up to 4mg daily, initially 25mg every 2 weeks; patients taking oral risperidone over 4mg daily, initially 37·5mg every 2 weeks; dose adjusted at intervals of at least 4 weeks in steps of 12·5mg to maximum 50mg (older people 25mg) every 2 weeks.

ZUCLOPENTHIXOL DECANOATE

Therapy notes

Formulation and dosage details

Formulation:

Solution for injection (oily) (Clopixol®) 200mg/mL, 500mg/mL

Dosage:

By deep intramuscular injection into the upper outer buttock or lateral thigh, test dose 100mg, followed after at least 7 days by 200 to 500mg or more, repeated at intervals of 1 to 4 weeks, adjusted according to response; maximum 600mg weekly. Older people, quarter to half usual starting dose.

Editorial Information

Document Id: F102