Alprazolam pharmacokinetics in women on low-dose oral contraceptives.
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 X 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.
Scavone
J M
JM
Department of Psychiatry, Tufts-New England Medical Center, Boston, MA 02111.
Greenblatt
D J
DJ
Locniskar
A
A
Shader
R I
RI
D000328:Adult; D000525:Alprazolam / Q000493:pharmacokinetics*; D002849:Chromatography, Gas; D003276:Contraceptives, Oral / Q000009:adverse effects*; D004347:Drug Interactions; D005260:Female; D006207:Half-Life; D006801:Humans
D003276:Contraceptives, Oral; D000525:Alprazolam