Monitoring of Inter-Dose Intervals for Long-Acting Injectable Antipsychotics: A Proposed Protocol for the MIDILIA Trial

Aims Service users taking long-acting injectable antipsychotics (LIAs) may experience recurrence of symptoms as they approach trough levels within a steady-state cycle. Limited research exists around symptom variation between peak-to-trough plasma concentrations LIA inter-dose intervals. Different LIAs have variable rates change in dopamine receptor occupancy during this due to differing elimination half-lifes. It is unclear what rate D 2 blockade tolerated by patients at present, which trial aims determine through observing severity differences variation. Methods A real-world observational longitudinal cohort study proposed. Inclusion criteria would be working-age adults (18–65 years) who received five consecutive and timely administrations consistent drug dose. The exclude anyone with significant hepatic or renal impairment, on concurrent oral antipsychotic medication deemed not yet their medication. Serum assays for level will obtained both peak an Expected timings determined derived tmax values from existing pharmacokinetic literature individual drugs. Trough taken 24 hours the next administration being due. Plasma then used calculate expected striatal using EC 50 maximal drugs PET scan data. Symptom assessed completing Positive Negative Scores (PANSS) questionnaires service time LIA. difference these scores plotted alongside concentrations. Results We hypothesize that correlate exponential manner, shorter half-life greater trough. expect able tolerate such degree without emergence symptoms; threshold most can tolerate, assist guiding how effectively reduce discontinue medications. Conclusion This outlines protocol monitor response intervals medication, ultimately aid reducing discontinuing antipsychotics.