Two-injection start regimen of long-acting aripiprazole for bipolar disorder: tips and tricks for better efficacy and tolerability.

Objective: To comparatively evaluate the efficacy and safety of the two aripiprazole long-acting injectable (LAI) initiation regimens, including one-injection start (OIS) regimen and two-injection start (TIS) regimen, in patients with bipolar disorder (BD). Methods: A total of 46 BD patients experiencing acute manic episodes with psychotic or mixed features were included in this observational study. Patients were divided into two groups based on the aripiprazole LAI initiation regimen including OIS group (n=23; patients received a single 400 mg LAI injection on Day 1, followed by oral aripiprazole (15-20 mg/day) for 14 days) and TIS group (n=23; patients received two 400 mg doses of aripiprazole LAI administered on the same day together with a single 20 mg oral dose of aripiprazole). Data on patient demographics, clinical characteristics and previous hospitalization were retrieved from hospital records. The effectiveness of the treatment was evaluated based on the Young Mania Rating Scale (YMRS) and Hamilton Depression Scale (HAM-D) scores recorded on Day 1 and Day 15 of the injection. The safety and tolerability of the OIS and TIS regimens were assessed via Udvalg for Kliniske Undersøgelser Side Effect Rating Scale (UKU-SERS) scores recorded on Day 15 of the injection. Results: At baseline, the rate of previous hospitalization was higher in the OIS group than in the TIS group (60.9% vs. 26.1%, p=0.037). YMRS scores on Day 15 (11.0 ± 5.7 vs. 16.6 ± 6.2, p=0.003) and UKU-SERS Psychiatric adverse effects score on Day 15 (4.4 ± 1.8 vs. 7.5 ± 3.2, p<0.001) were significantly lower in the TIS group than in the OIS group. YMRS scores and HAM-D scores were significantly decreased from Day 1 to Day 15 of injection in both TIS (p= 0.002 and p=0.025, respectively) and OIS (p= 0.002 and p=0.025, respectively) groups, while the change was significantly higher in the TIS group. Linear regression analysis revealed that OIS regimen was a significant risk factor for increase in YMRS Day 15 scores (B: 0.434, p=0.003) and increase in UKU-SERS psychiatric scores (B: 0.526, p<0.001). Logistic regression analysis revealed that OIS regimen was an independent determinant of previous hospitalization history (OR: 4.407, p=0.020), increasing the likelihood of previous hospitalization by 4.407 times compared to TIS regimen. Both regimens had tolerable side effects, with no life-threatening issues. Conclusions: This study highlights the efficacy and reliability of the TIS regimen in treating BD episodes, potentially facilitating faster clinical recovery by reducing the need for prolonged oral supplementation.