Pharmacokinetics and pharmacodynamics of terguride following intramuscular administration in cows and goats

The pharmacokinetics of intramuscular terguride (transdihydrolisuride) was evaluated in a single-dose study in cows (doses 100, 62 and 31 micrograms/kg b.w.) and goats (dose 100 micrograms/kg b.w.). A radioreceptor assay was used to quantitative plasma terguride concentrations. The peak plasma concentrations of terguride were attained within 0.6 h of the drug administration and then decreased monoexponentially with half-life of 1.3 h (cows) and 2 h (goats). The pharmacokinetics of terguride in cows is nearly linear. Pharmacodynamics of terguride was expressed as reduction in plasma prolactin levels. Maximal decline in prolactin was observed 3-4 h following terguride administration and the effect lasted for about 24 h.