Dr. Sederer: One of the things that we’ve learned is that antidepressants have a very beneficial effect for some people, but then they wear out and the person starts to relapse. Should ketamine be studied as an intervention for people who are no longer responding to the antidepressant(s) that they are on?
Dr. Mann: We do not really know the answer to that question. My experience treating very seriously ill patients is that sometimes the ketamine will work very well the first time or the second time but then in the future, if you try to use it as a rescue medication, it might not work that well. There is some clinical experience that suggests that that may be true for some people. But we have no idea about the frequency or timing with which this might happen. That’s all uncertain.
Moreover, most of our control clinical trial data come from either one dose of ketamine or from a few trials where people have received multiple doses of ketamine, followed by a bit of a taper. But there are very, very few of those types of studies. We’re still learning about the use of this medication.
Dr. Sederer: Importantly, you referenced the side effects of antidepressants. What are the side effects and risks of ketamine?
Dr. Mann: We know a lot more about the immediate short-term side effects of a single dose or a few doses of ketamine. Most people will get a kind of tripping experience. They’ll feel a bit unreal, or their circumstances or experiences of the world feel a bit distorted.
Some patients develop strange ideas. Most patients don’t enjoy those symptoms, even though I know ketamine is used as a party drug, and so on and so forth.
Dr. Sederer: It seems that the context is what matters.
Dr. Mann: Yes. And in a clinic context, most patients simply don’t enjoy these types of dissociative experiences, but they put up with them. They’re not severe, in general.
Dr. Sederer: Is part of the preparation of the patient telling them that this may happen?
Dr. Mann: Yes. We try to explain the potential for these symptoms and that most people get them. These side effects almost invariably terminate with the cessation of the administration.
Dr. Sederer: What’s the typical duration of the infusion you use?
Dr. Mann: Traditionally, infusion is 40 minutes and always in a clinic setting.
Dr. Sederer: And that’s because of the concern that a patient may have these symptoms?
Dr. Mann: Exactly. They may have dissociative effects that they’re disturbed by, and we need to monitor that. They’re probably going to remain under observation in the clinic for about the same amount of time because it takes about the same time for these effects to wear off.
The other consideration is that some people get a little nausea. In our experience with the intravenous ketamine, there’s also a problematic side effect that their blood pressure will be slightly raised. Therefore, it’s good to know that the person’s blood pressure is under control before they begin the treatments and that you’re monitoring it during administration.