Enhanced bioavailability of triazolam following sublingual versus oral administration

Abstract

The rate and extent of the absorption of triazolam following sublingual and oral administration were evaluated in this study. Eight healthy volunteers received triazolam 0.5 mg in a commercially available tablet, by sublingual and oral routes on two occasions in random sequence. Plasma triazolam concentrations during 24 hours after each dose were measured by electron-capture gas-liquid chromatography. The mean total area under the curve for sublingual administration was significantly larger than that following oral dosage (28.9 vs 22.6 ng-hr/mL, P less than .025). The peak plasma concentration after sublingual dosage was also higher than after oral administration (4.7 vs 3.9 ng/mL, P less than .1). No significant differences between sublingual and oral administration were found for the elimination half-life of triazolam (4.1 vs 3.7 hr) and the time of peak concentration (1.22 vs 1.25 hr) after dose. Thus, the bioavailability of triazolam after sublingual administration is increased by an average of 28% compared with oral administration of the same dose, possibly because first-pass extraction is bypassed. Clinical effects of triazolam may likewise be enhanced by sublingual dosage.