Lack of effect of sublingual salvinorin A, a naturally occurring kappa opioid, in humans: a placebo-controlled trial.
Psychopharmacology – April 01, 2011
Source: PubMed
Summary
Surprisingly, Salvinorin A, a compound from the hallucinogenic Salvia divinorum plant, showed no significant effects when administered sublingually to experienced users. Researchers investigated its physiological and subjective impact against a placebo. Eight participants received sublingual doses up to 4mg. Findings revealed no greater effects than placebo, nor did it mimic the plant's typical experiences. Although detectable, levels were very low, indicating poor absorption. This research clearly demonstrates Salvinorin A's limited sublingual bioavailability, offering crucial pharmacological understanding.
Abstract
Salvinorin A (SA) is a highly selective kappa opioid receptor agonist and the putative psychoactive compound in Salvia divinorum (SD), an increasingly abused hallucinogenic plant. The objectives of this study were to characterize the physiological and subjective effects of SA versus placebo and measure drug and metabolite levels. Sublingual SA doses up to 4 mg were administered in dimethyl sulfoxide/polyethylene glycol 400 solution to eight SD-experienced subjects using a placebo-controlled ascending-dose design. No dose of SA produced significantly greater physiological or subjective effects than placebo. Furthermore, effects did not resemble reported "typical" effects of smoked SD. SA was detectable in plasma and urine, but was, in most cases, below the reliable limit of quantification (0.5 ng/mL). Our results suggest that the sublingual bioavailability of SA is low. Higher doses, alternate formulations, or alternate routes of administration will be necessary to study the effects of SA in humans.