A preliminary study conducted at Oklahoma State University investigated the pharmacokinetics of CBD in horses. “We looked at one of the products being used as a supplement to see how much CBD and THC the horses absorbed,” explains Todd C. Holbrook, DVM, who is now at the University of Florida.
Pharmacokinetics of CBD
For the study, seven healthy horses received either a low or high dose of a CBD pellet product for seven consecutive days. “We pulled blood samples daily to look at the pharmacokinetics [the movement of the drug within the body], to see if the horses absorbed the CBD and how much; how long it takes to reach peak concentration in the plasma; and what the half-life was—how long it stayed in their system,” says Megan Williams, DVM, who worked on the study.
What the results showed
The results showed that CBD appeared in the plasma fairly rapidly, with a maximum concentration at approximately two hours. After an initial peak at two hours, plasma CBD concentrations reached a second peak about 24 hours after the first dose. In addition, the horses appeared to reach steady state concentrations of CBD by day three of the study.
During the study period, the researchers documented the horses’ temperature, heart rate and respiration daily. They also noted any signs of colic. No problems were found, Williams says, and “the horses seemed to tolerate CBD well at the doses given.”
A first step
This study is the first step in determining CBD’s potential therapeutic applications in horses, she says. “We now have information about plasma levels and what the half-life tends to be with oral CBD in horses.” Next will come efficacy studies to determine whether CBD can ease anxiety, reduce inflammation and/or relieve pain through clinical trials.
The safest effective doses must also be determined, says Holbrook, adding that “whether CBD is a better option or not has yet to be determined. But it has some science behind it in humans for managing epilepsy and its ability to impact/relieve anxiety. Studies and models for assessing anxiety are challenging to do in horses.”
