Horse Tranquilizer Effects On Humans: Understanding the Truth About Ketamine Treatment

About the Author Dr. Steven P. Levine is a board-certified psychiatrist internationally recognized for his contributions to advancements in mental health care. Though he is a psychiatrist who places great emphasis on the importance of psychotherapy, medication is often a necessary component of treatment, and he was dissatisfied with the relatively ineffective available options with burdensome side effects. Dr. Levine pioneered a protocol for the clinical use of ketamine infusions, has directly supervised many thousands of infusions and has helped establish similar programs across the country and around the world.To dispel the myth of “ketamine the horse tranquilizer,” let’s start with the truth:

Ketamine Horse Tranquilizer Effects On Humans: Dispelling the Myth

Ketamine is a commonly used anesthetic drug (not tranquilizer) in veterinary medicine.I have a well-rounded sense of humor, but draw the line when lives are at stake. Referring to ketamine as a horse tranquilizer in the media may catch eyes, but its lure does more harm than good.  A refined headline would be “Cat Anesthetic For Treatment-Resistant Depression,” but even that is inaccurate considering the origin and overall usage of ketamine. Ketamine was developed in the 1960s as a prescription drug for anesthesia during surgery and is still being used in emergency rooms and field hospitals. It is considered among the safest medications by the World Health Organization.¹ Like many medications developed for human consumption, ketamine found its way into veterinary medicine. Here’s a short list of other medications creatures take:

A lot of medicines work across species—it’s the dose per species and then per life-form that is unique. When you call ketamine a horse tranquilizer, it evokes imagery of a drug so strong it can knock out a horse (just imagine the effect on a human body), but the amount of veterinary ketamine it takes to anesthetize a horse is much larger than what a human requires for depression treatment. The amount of anything consumable is a crucial consideration we often take for granted. Consider the following:

When treating patients, we use safe, human-appropriate doses of ketamine, which are around 10 times smaller than what is used during surgery. The starting dose is unique per patient, based on factors like weight. IV infusions maintain tight control over the rate of administration; vital signs are monitored; our staff is highly trained in advanced life support. Our protocol is based on two decades worth of researching the benefits of ketamine use for depression in humans, not horses. While there is potential for ketamine abuse (you’ve probably heard of a k-hole), the brain has NMDA receptors that benefit from ketamine in a medical setting when used intravenously. Depression symptoms and some chronic pain can be rapidly treated with this so called horse-tranquilizer.

Ketamine was a breakthrough 20 years ago. Now, it’s a time-tested fact, well known in the international medical community as an advanced, robust off-label weapon in the fight against depression and other conditions.² Calling it a horse tranquilizer, after all we’ve learned, is misleading and may stop suffering individuals from considering an alternative that may work when everything else fails. So if you wouldn’t mind, change the headline.


  1. World Health Organization. (2016, March). Fact file on Ketamine.
  2. Sanacora G, Frye MA, McDonald W, et al. A consensus statement on the use of ketamine in the treatment of mood disorders. JAMA Psychiatry. 2017;74(4):399-405. doi:10.1001/ jamapsychiatry.2017.0080.