Two open-label, randomized, parallel-arm studies compared pharmacokinetics, safety, and tolerability of aripiprazole once-monthly 400 mg (AOM 400) following deltoid versus gluteal injection in patients with schizophrenia.
In the single-dose study, 1 injection of AOM 400 in the deltoid (n=17) or gluteal (n=18) muscle (NCT01646827) was administered. In the multiple-dose study, the first AOM 400 injection was administered in either the deltoid (n=71) or gluteal (n=67) muscle followed by 4 once-monthly deltoid injections (NCT01909466).
After single-dose administration, aripiprazole exposure (area under the concentration-time curve [AUC]) was similar between deltoid and gluteal administrations, whereas median time to maximum plasma concentration (tmax) was shorter (7.1 (deltoid) vs 24.1 days [gluteal]) and maximum concentration (Cmax) was 31% higher after deltoid administration. In the multiple-dose study, median tmax for deltoid administration was shorter (3.95 vs 7.1 days), whereas aripiprazole mean trough concentrations, Cmax, and AUC were comparable between deltoid and gluteal muscles (historical data comparison). Multiple-dose pharmacokinetic results for the major metabolite, dehydro-aripiprazole, followed a similar pattern to that of the parent drug for both deltoid and gluteal injection sites. Safety and tolerability profiles were similar after gluteal or deltoid injections. Based on observed data, minimum aripiprazole concentrations achieved by AOM 400 are comparable with those of oral aripiprazole 15 to 20 mg/d.
The deltoid muscle is a safe alternative injection site for AOM 400 in patients with schizophrenia.