No guidance exists for aripiprazole LAI medications; however, based on the pharmacokinetic data, administration of oral medications should be initiated at the date of next injection. Given the long half-life of aripiprazole, a cross-titration of the LAI with oral medication is reasonable.
Monitoring drug levels
In addition to utilizing the pharmacokinetic data from LAI antipsychotics, therapeutic drug levels can be instrumental in determining the dose of oral medication to use and when to begin titration (Table 2).12-14 Obtaining a drug level on the date of the next injection can provide the clinician with data regarding the release of the medication specific to the patient. Based on the level and the current symptomatology, the clinician could choose to start the oral medication at a lower dose and titrate back to the LAI equivalent oral dose, or initiate the oral dose at the LAI equivalent oral dose. Continued therapeutic drug levels can aid in this determination.
No guidance exists on the appropriate discontinuation of LAI antipsychotics. Utilizing a medication’s half-life and release mechanism, as well as the patient’s previous medication history, date of last injection, and therapeutic drug levels, should be considered when determining the schedule for restarting an oral antipsychotic.
CASE CONTINUED
Based on the current dosing of paliperidone palmitate of 156 mg once a month, Mr. R likely requires 9 mg/d of oral paliperidone upon discontinuation of the LAI. On the date of the next injection, the clinician could decide to initiate a lower dose of paliperidone, such as to 3 mg/d or 6 mg/d, and increase the dose as tolerated over the next 10 to 14 days as the paliperidone palmitate is further metabolized. Additionally, the clinician may consider obtaining a therapeutic drug level to determine the current paliperidone level prior to initiating the oral medication. Each treatment option offers individual risks and benefits. The decision on when and how to initiate the oral medication will be based on the individual patient’s situation and history, as well as the comfort and discretion of the clinician. The clinician should arrange appropriate monitoring for potential increased symptomatology during the transition, and adverse effects should be assessed regularly until steady state is achieved with the targeted oral dose of medication.
Related Resources
- Parmentier BL. Second-generation long-acting injectable antipsychotics: a practical guide. Current Psychiatry. 2020;19(3):24-32.
- Thippaiah SM, Fargason RE, Birur B. Switching antipsychotics: a guide to dose equivalents. Current Psychiatry. 2021;20(4):13-14. doi:10.12788/cp.0103
Drug Brand Names
Aripiprazole lauroxil • Aristada
Aripiprazole monohydrate • Maintena
Haloperidol injection • Haldol decanoate
Olanzapine pamoate • Zyprexa Relprevv
Paliperidone • Invega
Paliperidone palmitate once monthly • Invega Sustenna
Paliperidone palmitate every 3 months • Invega Trinza
Paliperidone palmitate every 6 months • Invega Hafyera
Risperidone microspheres • Risperdal Consta
Risperidone polymer • Perseris