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.

Establishing Tolerability

• Prior to initiating Risperdial Consta, establish tolerability with oral risperidone in risperidone-naïve patients.

Dosing

• Risperdal Consta is given IM every two weeks.
• Risperdal Consta is available as 12.5 mg (lowest dose) and 50 mg (highest dose); and as intermediate doses of 25 mg and 37.5 mg.
• Initiating Consta requires overlap with oral risperidone (at a therapeutic dose) for 3 weeks.
• There is no established loading-dose strategy.
• In general, Consta is initiated with the 25 mg dose unless clinical factors suggest to start with 12.5 mg.
• Adjustment in dose should not be made more frequently than every 4 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.
• The recommended dose is 25 mg IM every 2 weeks.

  Dose Conversion of Oral Risperidone to Risperidone Microspheres LAI
  PO Dose	LAI/IM 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.  References: 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.

Practical issues (including administration)

• Risperdal Consta needs to be refrigerated, reconstituted and warmed up which poses some workflow issue in clinics. Just before injection, shake syringe vigorously again, as some settling will have occurred. Risperdal Consta kits should be taken out of the refrigerator for 30 minutes prior to injection.
• Use only components of the pre-packed dose packages containing the drug and syringe prefilled with diluent. Follow instructions from package insert regarding reconstitution.
• 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.
• 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.

FDA Medication Label

Information on this topic is found in the FDA medication label.  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.