FDA Approves Once-Monthly Olanzapine Injection for Adults With Schizophrenia

The FDA has approved olanzapine extended-release injectable suspension (Weltruza; Teva) for adults with schizophrenia. The once-monthly subcutaneous treatment requires no loading dose, oral supplementation, or postinjection monitoring, according to an October 9 announcement from Teva. The company expects it to become available in the US in the coming weeks.¹

Weltruza is the first approved once-monthly subcutaneous formulation of olanzapine. Its 318-mg, 425-mg, and 531-mg doses correspond to oral olanzapine doses of 10 mg, 15 mg, and 20 mg daily, respectively, Teva said.¹ The previously available long-acting intramuscular olanzapine product requires a 3-hour observation period after each injection because of the risk of postinjection delirium/sedation syndrome (PDSS).⁴

Approval was supported by the phase 3 SOLARIS trial, which enrolled 675 adults aged 18 to 64 years with schizophrenia. During an 8-week randomized, double-blind period, participants received monthly subcutaneous olanzapine at one of three doses or placebo. All three doses met the primary endpoint of change in Positive and Negative Syndrome Scale (PANSS) total score from baseline to week 8. The placebo-adjusted differences were −9.71 points for the high dose, −11.27 points for the medium dose, and −9.71 points for the low dose (adjusted P<.001 for each comparison). Clinical Global Impressions–Severity and Personal and Social Performance scores also improved significantly versus placebo, Teva reported.¹˒²

Participants could then enter an open-label safety period lasting up to 48 weeks. In a company-reported analysis through week 56, no suspected or confirmed PDSS events occurred across 3470 injections. That finding does not establish that the risk is absent: Teva’s safety information states that it is unknown whether PDSS can occur with Weltruza.¹˒³

The formulation retains the metabolic concerns associated with olanzapine. In the long-term SOLARIS analysis, increased weight was reported in 36% of participants receiving injectable olanzapine. Injection-site induration and pain each occurred in 12%, erythema in 10%, pruritus in 7%, and somnolence in 7%. Among 137 participants treated for at least 48 weeks, mean weight gain from baseline was 5.6 kg, according to Teva.³ The company’s approval announcement also listed headache and constipation among commonly reported adverse events.¹

Weltruza carries the antipsychotic boxed warning for increased mortality in older adults with dementia-related psychosis and is not approved for that use. For clinicians considering a switch from oral therapy, the simpler monthly administration must be weighed alongside olanzapine’s potential for clinically significant weight gain, hyperglycemia, and dyslipidemia. The placebo-controlled phase of SOLARIS lasted 8 weeks; the longer safety findings came from an open-label period.¹˒³

References

1. Teva. FDA approval of Weltruza for adults with schizophrenia. October 9, 2026.
2. Teva and Medincell. Phase 3 SOLARIS efficacy results. May 2024.
3. Teva. Long-term SOLARIS safety data. September 2025.
4. FDA. Zyprexa Relprevv prescribing information. 2026.