I’ve used it, Periwinkle can also cause a false positive…and some history
FWIW I have used Reserpine on one horse who was on stall rest and started to lose his mind. He kicked out the back window of a car (while we were “hand grazing”) before I decided to give it to him.
Until yesterday it was still in my med box, however. Beside a lot of the other drugs that get used on a much more frequent basis.
from: http://barrelhorsenews.com/articles/horse-health/3795-altered-states
Reserpine
Reserpine is one of the world’s oldest tranquilizers. Made from the climbing vine Rauwolfia serpentina native to India, it was known in ancient Hindu writings as the “insanity herb” and was used to treat high blood pressure, insomnia, and of course, insanity. Its ability to lower blood pressure made it valuable as a treatment for snakebites, and a particularly handy drug in a land populated by some of the world’s most deadly vipers. Mahatma Gandhi was said to have used reserpine as a tranquilizer, and ancient texts have Alexander the Great using it to treat his general Ptolemy, who had fallen in battle to a poison arrow.
The “Indian Snakeroot” made its way into modern medicine prior to World War II, when two Indian doctors first reported of its antipsychotic properties in a Western medical journal.
“Reserpine and acepromazine were introduced into Western medicine at about the same time,” notes Tobin, who did his PhD in pharmacology under the direction of Amar Sen, whose father was one of the introductory Indian doctors. “Reserpine was so long-lasting that they were overdosing patients. Its effects are relatively quite long lasting; the effect of a single dose can last up to maybe 30 days, but they would dose the drug daily. Psychiatrists then found that their patients were getting depressed and committing suicide, and they concluded that reserpine was unmasking latent suicidal tendencies, which was somewhat unlikely; much more likely was that it was simply an overdose situation.”
Today it’s rarely used as a human antipsychotic, but is still used to manage high blood pressure when other medicines have failed.
Although not FDA approved for use in horses, reserpine was once considered a possible treatment for fescue toxicity that causes gestational problems and abortion in mares, but its principal use in equine medicine today is to take the edge off excitable or difficult to manage horses.
“It’s a very subtle, long-acting tranquilizer,” says Tobin. “It’s a relatively potent drug. It’s also very difficult to detect. When we started this business [of drug detection] 30 years ago, we couldn’t detect a couple of milligrams of a substance like reserpine. On the other hand, one needs to keep in mind that testing is now about 1 million times more sensitive than when I started in this business 35 years ago, and nowadays virtually all drugs and medications are readily detectable, and some for quite long periods post-administration.”
Although highly detectable by today’s drug tests, a positive result can be complicated by the presence of trace amounts of similar substances from native plants, like periwinkles, that are found in some areas of the United States, particularly in the Southeast.
Today’s drug tests are very sensitive and can detect very trace amounts of forbidden substances. For instance, a common plant, like periwinkles, can cause a horse to test positive for reserpine.
Today’s drug tests are very sensitive and can detect very trace amounts of forbidden substances. For instance, a common plant, like periwinkles, can cause a horse to test positive for reserpine.
Like other tranquilizers, reserpine is highly dose dependent.
“You can take the edge off a horse for up to two weeks with small doses of reserpine, if you’ve got the right horse and the right dose,” says Tobin. “The first day the horse may be a little depressed, have a little diarrhea or flatulence, but after two days or so, he’s normal to visual inspection, but if you know the behavior of the horse well, and especially if you know him to be excitable and difficult to manage, you will know he’s tranquilized.”
The use of reserpine in this manner is largely unstudied, but anecdotal evidence suggests that the drug may, in very rare instances, cause penile prolapse in male horses, thus making penile paralysis a possible side effect. Other possible side effects include violent colic, diarrhea and sweating over the back and hindquarters.
The reactions to reserpine can be variable among horses. Warns Tobin, “You need to know how to use it and it also helps to know your horse.”
Read more: http://barrelhorsenews.com/articles/horse-health/3795-altered-states#ixzz2hylNHIwn
