LONG-ACTING INJECTABLE ANTIPSYCHOTICS — Long-acting injectable antipsychotics are generally used in patients with a history of relapse due to poor adherence to oral maintenance therapy. They are believed to improve adherence, hospitalization and relapse rates, and long-term outcomes in patients with schizophrenia, even though a benefit has not been consistently demonstrated in controlled trials comparing long-acting injectable formulations with oral second-generation antipsychotics.1,2

CLINICAL STUDIES — FDA approval of Invega Hafyera was based on the results of an unpublished (summarized in the package insert) double-blind, active-controlled, noninferiority trial in 702 adults with schizophrenia. At 12 months, a relapse event occurred in 7.5% of patients who received Invega Hafyera every 6 months and in 4.9% of those who received the drug every 3 months (Invega Trinza); twice-yearly paliperidone was noninferior to the drug given every 3 months.

ADVERSE EFFECTS — Adverse effects of the new twice-yearly paliperidone palmitate formulation appear to be similar to those with the other injectable ER formulations of the drug.

DRUG INTERACTIONS — Concurrent use of strong CYP3A4 and P-glycoprotein (P-gp) inducers can decrease serum concentrations of paliperidone and should be avoided; if coadministration is necessary, oral paliperidone extended-release tablets can be added.3 Paliperidone may antagonize the effects of levodopa and other dopamine agonists.

DOSAGE AND ADMINISTRATION — Invega Hafyera is injected into the gluteal muscle once every 6 months. The starting dosage (1092 or 1560 mg) is based on the previous dose of the monthly or 3-month injectable ER formulations of paliperidone palmitate and should be administered at the time the next dose of paliperidone palmitate is scheduled. Dosage adjustments can be made every 6 months between 1092 mg and 1560 mg. Invega Hafyera is not recommended for use in patients with any degree of renal impairment (CrCl <90 mL/min).

REFERENCES