Pharmacokinetics of levosulpiride after single and multiple intramuscular administrations in healthy Chinese volunteers

The main purpose of this study was to evaluate the pharmacokinetics of levosulpiride in humans after single and multiple intramuscular injections. Six males and six females received single dose of either 25 mg or 50 mg levosulpiride, or multiple doses of 25 mg every 12 h for 5 consecutive days. In the single 25 mg study, the mean peak plasma concentration (C(max)) was 441 ng/mL, the mean area under the concentration–time curve from 0 to 36 h (AUC(0–36)) was 1724 ng h/mL, and the mean elimination half-life (t(1/2)) was 7.0 h. In the single 50 mg study, the mean C(max) was 823 ng/mL, the mean AUC(0–36) was 3748 ng·h/mL, and the mean t(1/2) was 6.8 h. After multiple doses of 25 mg levosulpiride, the average plasma concentration (C(av)) was 136 ng/mL, the fluctuation index (DF) was 3.60, and the accumulation ratio (R) was 1.2. Levosulpiride injections appeared to be well tolerated by the subjects, and can be used for successive administration.