What should clinicians know about risperidone or Risperdal Consta (“Consta”) (risperidone microspheres LAI)?

Risperdal Consta was the first of the second-generation antipsychotics that became available as a long-acting injectable antipsychotic.  The efficacy and side effect profile corresponds to oral risperidone.  It is FDA-approved for the treatment of schizophrenia and for the maintenance treatment of bipolar 1 disorder.

Risperdal Consta 



Dosing available as prefilled syringes

12.5 mg (2 mL)
25 mg (2 mL)
37.5 mg (2 mL)
50 mg (2 mL)

Recommended starting and maintenance dose

The recommended dose is 25 mg IM every 2 weeks.
Consta is initiated with the 25 mg dose unless clinical factors suggest to start with 12.5 mg.

Drug Metabolizing Enzyme


Dosing exclusions

Patients with renal or hepatic impairment should be treated with titrated doses of oral Risperdal prior to initiating treatment with Risperdal Consta.

Loading dose

No established loading-dose strategy.

Oral overlap

Initiating Consta requires overlap with oral risperidone (at a therapeutic dose) for 3 weeks.
Risperdal Consta 12.5 mg IM every two weeks corresponds to 1 mg oral risperidone per day. This means that the highest available Consta dose of 50 mg IM every two weeks corresponds to 4 mg oral per day. For many chronic patients with schizophrenia, this is at the low end of the dose range. Since Consta injections should not be combined, clinicians sometimes supplement Consta with oral risperidone if a higher dose is desired.

Establishing tolerability


Requires refrigeration

Reconstitution or mixing

Use only components of the pre-packed dose packages containing the drug and syringe prefilled with diluent. Follow instructions from package insert regarding reconstitution.

Injection site

Deltoid or gluteal injections are bioequivalent; the site can be chosen based on patient preference. Alternate sites and use 1-inch needle for deltoid, 2-inch needle for gluteal injection.

Injection interval

Every 2 weeks


Allow product to come to room temperature for at least 30 minutes before reconstituting.  Flip the cap from the vial.  Attach the vial adapter to the vial.  Swab the syringe connection point with an alcohol pad.  Snap the white cap off the prefilled syringe.  Attach the syringe to the vial adapter.  Inject the entire contents of the syringe containing the diluent into the vial. Shake the vial vigorously while holding the plunger rod down with the thumb for a minimum of 10 seconds to ensure a homogeneous suspension.  If 2 minutes pass before injection, re-suspend by shaking vigorously.  Invert the vial completely and slowly withdraw the suspension from the vial into the syringe.  Unscrew the syringe from the vial adapter and inject per package insert instructions.  Priming of the syringe is recommended.

Administration considerations

The injection is water-based which is less painful than decanoates. You don’t need to push hard.
Always give the full vial that you selected (the microspheres are not evenly distributed in the syringe). You should also not combine different doses of Consta.

Timing variations


When a dose is missed



Additional information

Adjustment in dose should not be made more frequently than every 4 weeks.
This product is now available generically. 

Dose Conversion of Oral Risperidone to Risperidone Microspheres LAI

PO Dose 


1 mg daily

12.5 mg (injection volume of 2 ml) every 2 weeks

2 mg daily

25 mg (injection volume 2 ml) every 2 weeks

3-5 mg daily

37.5 mg (injection volume 2 ml) every 2 weeks

4-5 mg daily

50 mg (injection volume 2 ml) every 2 weeks

Recommended available dose formulations include 12.5 mg, 25 mg, 37.5 mg, and 50 mg pre-filled vial kits.

Dose reduction may be necessary for CYP450 interactions, in patients with hepatic or renal impairment, or in patients who have a history of poor tolerability to psychotropic medications. 

1. Bai, Y.M., Chen, T.T., Chen, J-Y., Chang, W-H., Wu, B., Hung, C.H., & Lin, W.K. (2007). Equivalent switching dose from oral risperidone to risperidone long-acting injection: A 48-week randomized, prospective, single-blind pharmacokinetic study. Journal of Clinical Psychiatry, 68(8), 1218-1225. doi: 10.4088/jcp.v68n0808.
2. Stahl, S. M. (2017). The prescriber’s guide: Stahl’s essential psychopharmacology (6th ed.). New York: Cambridge University Press.
3. American Psychiatric Association. (2020). The American Psychiatric Association Practice Guideline for the Treatment of Patients With Schizophrenia. American Psychiatric Association Publishing. https://doi.org/10.1176/appi.books.9780890424841
4. RISPERDAL CONSTA USPI Section 2.1: Schizophrenia; Section 2.2: Bipolar Disorder; Section 2.3: General Dosing Information; Section 2.8: Instructions for Use

5. Taylor, D.M., Barnes, T.R.E, & Young, A.H. (2021). The Maudsley prescribing guidelines in psychiatry (14th ed.). Wiley Blackwell. 

FDA Medication Label

Information on this topic is found in the FDA medication label.  Not all information in the FDA medication label is included here, and clinicians should read the entire FDA medication label before making treatment decisions.

Prescribing should always be informed by the FDA medication label. Medication labels can be found by searching Drugs@FDA at the FDA website. Labels are also available using the Drugs@FDA app for Apple or Android devices.

Labels change over time, and the current label should always be consulted. Here is the most recent label, at time of writing.

If you would like more information on this topic, or would like to provide any feedback, please send us a message using our consultation system. Be sure to let us know about which tip you are writing. We would love to hear from you, and the consultation system is free to use and confidential. Thank you!
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