Study of the detection of valerian administration in equine plasma and urine

Abstract or Summary

Valerian root (the rhizome, stolons and roots of Valeriana officinalis) is in common use to help calm nervous horses. Rumoured abuse of this medicine in equestrian events has resulted in increased surveillance by testing laboratories. Competitors are concerned that Valerian root used as a training aid may result in positive detections in competition samples. The aim of this study was to establish a reliable withdrawal period prior to competition after a course of Valerian. Ten horses (one colt, 4 fillies and 5 geldings aged between 2 and 15 years) were administered, twice daily, 40 mL of a 1:2 extract of Valerian root in 45% alcohol for a period of 7 days. Blood samples were collected before dosing, about 9 h after the final dose and then every 24 h for 5 days. Urine samples were collected, when naturally voided by the individual animals between 4 and 11.5 h after the final dose and then daily for 5 days. Analysis for valerenic acid and 1-hydroxyvalerenic acid in equine plasma and urine was carried out by GCMS analysis of the methyl derivatives following liquid/liquid extraction (plasma) or solid phase extraction (urine). Valerenic acid and 1-hydroxyvalerenic acid were detected only in the urine samples obtained on the day of the final dose. Seven of the 10 horses yielded these samples. Neither of these substances was detected in the plasma samples from any of the horses. Given in the form of an aqueous ethanol extract, Valerian appears to be absorbed and eliminated rapidly. A withholding period of 24 h should be adequate for this product.