Hantavirus Cluster Linked to Cruise Ship Travel: A Comprehensive Review of a Looming Global Public Health Concern.

Haloperidol is a high-potency, first-generation antipsychotic (FGA) indicated for the treatment of schizophrenia and bipolar disorder. It is available in several formulations, including oral tablets, an oral solution, an immediate-release intramuscular injection, and a long-acting injectable (LAI) decanoate formulation. Haloperidol is often used in settings where patients are unable to tolerate second-generation antipsychotics (SGAs) due to metabolic adverse effects, have demonstrated treatment resistance following multiple SGA trials, or require an LAI formulation but have limited access to costlier SGA LAIs. For patients who respond to and tolerate oral haloperidol, transitioning to the LAI formulation may improve adherence, especially among those with a history of poor adherence or a preference for the injectable formulation. LAIs, including haloperidol decanoate, offer several benefits for those with serious mental illness, as outlined in the 2020 American Psychiatric Association guidelines. Haloperidol decanoate dosing is not standardized and varies significantly by prescriber and institution. The manufacturer recommends an initial dose conversion of 10 to 20 times the previous daily oral haloperidol dose. For patients receiving lower oral doses, such as elderly individuals, an initial dose of 10 to 15 times the daily oral dose is suggested. In contrast, for patients receiving higher oral doses and at risk for decompensation, up to 20 times the oral dose may be considered with a downward taper on succeeding injections. Regardless of a high or low oral to LAI dose conversion, the initial dose should not exceed 100 mg, thus requiring a split initial dose separated by 3 to 7 days as needed. Owing to the delayed intramuscular absorption of haloperidol decanoate, oral haloperidol supplementation may be required during the first 6 weeks of therapy. Anecdotally, the duration of oral supplementation is often continued beyond 6 weeks to ensure therapeutic concentrations are maintained and to minimize the risk of relapse. Additionally, several haloperidol decanoate loading-dose protocols have been evaluated, all generally adhering to the 10 to 20 times oral dose conversion. Despite these recommendations, anecdotal evidence suggests that prescribers are initiating doses outside of the recommended range, potentially placing patients at risk for extrapyramidal symptoms (EPS) or relapse. Because of the great heterogeneity in haloperidol decanoate dosing and oral supplementation approaches, there is a need to examine institutional dosing practices of haloperidol decanoate. Specifically, evaluating and characterizing current prescribing patterns that deviate from manufacturer labeling-based dosing will provide clarity. The purpose of this medication use evaluation was to assess prescribing patterns in adult inpatients with schizophrenia or schizoaffective disorder for initial haloperidol decanoate administration and to analyze associated secondary factors.