# 95 - Risperidone intramuscular long acting injecti

# Risperidone intramuscular long-acting injections

Schizophrenia and related psychoses
CHAPTER 1
Risperidone long-­acting injection
In this section we give brief details on the range of risperidone LAIs (RLAIs) available 
around the world in 2024. We have done our best to identify each formulation by some 
unique property and by a trade name. These trade names do vary somewhat by country. 
Readers are directed to formal product information for full details of each 
formulation.
Risperidone intramuscular long-­acting injections
Risperdal Consta – risperidone 2-­weekly long-­acting injection
RLAI is now very rarely initiated in practice and here we give no information on starting doses or its therapeutic uses. It has been superseded by longer-­acting risperidone 
and paliperidone injections with less complex pharmacokinetic profiles. Here we provide information on stopping RLAI and on switching to other formulations. In doing 
this, we have relied upon the following assumptions:1
Weeks after last injection
4
Consta injection given
0
10
20
2
6
Weeks
Active moiety (ng/ml)
10
First missed dose
Second missed dose
Figure 1.1  Blood levels following discontinuation of treatment with 25mg every 2 weeks: last 
­injection at week 4. Source: reproduced with permission from Wilson (2004).2
Timescale of plasma concentrations after last dose of RLAI
4–5 weeks
Peak plasma concentration from last dose reached
6 weeks
Plasma levels fall below threshold for therapeutic effect
7–8 weeks
Plasma concentrations approach zero
Switching from RLAI is complicated because, in regular dosing, plasma concentrations 
remain therapeutic for around 6 weeks following the last injection. Two weeks after the 
last injection (i.e. the time of the first missed injection) plasma levels are yet to peak and 
will in fact reach a peak on two occasions after this time (Figure 1.1).

100
The Maudsley® Prescribing Guidelines in Psychiatry
CHAPTER 1
Table 1.23 provides general recommendations when switching from RLAI. These 
suggestions are aimed at ensuring that, when switching someone who is responsive to 
RLAI, a therapeutic plasma concentration of the new antipsychotic is established before 
risperidone concentrations become sub­therapeutic. A further aim is to ensure that 
therapeutic levels of the new drug will be maintained during the first dosing interval.
Rykindo®
Rykindo is a 2-­weekly injectable suspension of risperidone given in the gluteal muscle 
to patients who have previously responded and tolerated risperidone.8 After IM injection risperidone blood concentration peaks at 14 days and reaches steady state after 
two administrations. Oral supplementation is required for the first 7 days of treatment. 
The recommended starting dose is 25mg every 2 weeks, with a maximum dose of 50mg 
every 2 weeks. Dose adjustments can be made every 4 weeks.
Patients on Consta can switch directly to Rykindo without needing oral supplementation. The first IM injection should be given 4–5 weeks after the last Consta administration (refer to Table  1.25 later in this section for equivalent doses). Like Consta, 
Rykindo must be stored in the refrigerator and allowed to sit at room temperature for 
at least 30 minutes before reconstitution. The reconstitution process is similar to that 
for Consta. Please refer to manufacturer’s advice for further details.
Table 1.23  Switching from risperidone long-­acting injections.3,4
Switching to
Recommended method of switching
Comments
Oral risperidone
Start oral tablets 4–5 weeks after the last 
RLAI injection
25mg/2 weeks = 2mg/day
37.5mg/2 weeks = 3mg/day
50mg/2 weeks = 4 mg/day5
Oral antipsychotic 
(not risperidone)
Start oral antipsychotic 4–5 weeks after the 
last RLAI injection
Monitor for adverse effects
Paliperidone LAI6
Initiate the equivalent dose of the 
paliperidone LAI in place of the next 
scheduled dose of RLAI, then continue 
monthly administration (a second loading 
dose is not required and should not be given)
25mg/2 weeks = 50mg/monthly
37.5mg/2 weeks = 75mg/monthly
50mg/2 weeks = 100mg/monthly
Risperidone ISM®* 
(Okedi, Risvan, and 
others)7
Initiate the equivalent dose of risperidone ISM 
in place of the next scheduled dose of RLAI and 
continue risperidone ISM at 28-­day intervals
37.5mg/2 weeks = 75mg/28 days
50mg/2 weeks = 100mg/28 days
Aripiprazole LAI
Start oral aripiprazole 4–5 weeks after the 
last RLAI dose. Initiate ALAI 2 weeks after 
starting oral aripiprazole.
Note that aripiprazole LAI can be 
initiated in two ways. For more 
information refer to the relevant section 
of this book and manufacturer’s advice.
Antipsychotic LAI 
(not paliperidone or 
risperidone ISM)
Start the new LAI 4–5 weeks after the last 
RLAI
For some LAIs, oral trial and/or test 
dose may be required to establish 
response and tolerability
* Formal recommendations recommend giving risperidone ISM in place of the next RLAI injection; i.e. 2 weeks after 
the last injection. A 4-­week interval makes more sense because risperidone ISM will then be given shortly before the 
time of peak plasma levels from the last RLAI injection.