Alprazolam Pharmacokinetics in Women on Low‐Dose Oral Contraceptives

Publisher Website
Google Scholar
Abstract
Sixteen women chronically using low‐dose estrogen‐containing oral contraceptive steroids (OCs) and 23 drug‐free control women received a single 1‐mg oral dose of alprazolam. Multiple plasma samples drawn during 48 hours after the dose were analyzed by electron‐capture gas‐liquid chromatography. There were no significant differences between controls and oral contraceptive users in alprazolam volume of distribution (1.27 versus 1.39 L/kg), elimination half‐life (11.9 versus 12.3 hours), total clearance (1.36 versus 1.39 mL/min/kg), or total area under the plasma concentration versus time curve (227 versus 243 ng/mL × hr). Alprazolam free fraction in plasma was slightly but significantly greater in the oral contraceptive group as opposed to the control group (28.4 versus 27.0% unbound), respectively. However, comparison of free clearance between groups revealed no significant difference (4.61 versus 4.89 mL/min/kg, respectively). Thus, low‐dose estrogen‐containing oral contraceptives do not significantly influence the metabolic clearance of alprazolam.