Pharmacokinetic comparison of intranasal, oral, and intramuscular metoclopramide in healthy volunteers.

This was a randomized, crossover study of the bioavailability and pharmacokinetics of metoclopramide given by intranasal (IN), oral (PO), and intramuscular (IM) routes. The formulations tested were 5 and 10 mg of IN gel, 10 mg PO, and 5 mg IM. The findings showed that metoclopramide follows similar absorption and elimination characteristics when given via these three extravascular routes. There were no statistically significant differences in the area under the drug concentration versus time curve (AUC) or peak metoclopramide plasma concentration (Cmax) data following PO, IM, or 10-mg IN administration. However, the 5-mg IN doses achieved an AUC that was 39.5% the AUC of the 10-mg IN dose. These data show consistent and relatively predictable metoclopramide plasma concentrations following IN administration. Further, 10-mg doses of IN and PO metoclopramide appear to be bioequivalent.