Who Is Not a Good Candidate for Ketamine Therapy

I turn people away from ketamine treatment. Not often, but regularly enough that I want to write down why, because almost everything published about this treatment is addressed to people who are going to receive it.

The screening is the part that makes the treatment safe. A clinic willing to infuse anyone who can pay is not offering you convenience, it is skipping the step that protects you. So here is what I look at, and what makes me say no.

Blood pressure and the heart

Ketamine reliably raises blood pressure and heart rate during an infusion. In someone with normal cardiovascular function, the rise is modest, expected, and resolves as the infusion ends. In someone whose blood pressure is already uncontrolled, the same rise is a real hazard.

Uncontrolled hypertension is the reason I decline patients most often. It is also the most fixable, which is why I tell people the door is not closed. Work with your primary care physician, get the numbers into range, and come back. I have treated many patients who were declined in the spring and infused without incident in the fall.

Unstable angina, a heart attack within the past six months, poorly controlled arrhythmia, significant heart failure, and an untreated aneurysm all carry similar concerns and require cardiology input before I will proceed.

Psychosis

A history of schizophrenia or any psychotic disorder is a firm no. Ketamine produces temporary dissociation and perceptual changes by design, and in a brain prone to psychosis those effects can precipitate an episode that outlasts the infusion by a long way. This holds even when the current presenting problem is depression and the psychotic illness has been quiet for years.

Active mania is the same answer for different reasons. Bipolar depression can respond well to ketamine, and I treat it, but only when mood is stable and the patient is on an adequate mood stabilizer. Infusing someone who is trending toward mania can accelerate it.

Substance use history

Ketamine is a controlled substance with genuine misuse potential, and a history of ketamine or other dissociative misuse rules someone out.

Other substance histories are handled case by case rather than as a blanket exclusion. Someone with years of sustained recovery from alcohol or opioid use is often a reasonable candidate, and the depression underneath that history is frequently what put them at risk in the first place. Someone who is actively drinking heavily or using stimulants is not, both because of interaction risk and because a treatment that produces an altered state is poorly timed for someone whose relationship with altered states is the current problem. Where the picture is complicated, I would rather treat the substance use first and revisit this.

The medication list

I go through it line by line, and a few items change the plan.

Benzodiazepines appear to blunt ketamine’s antidepressant effect, with higher daily doses associated with weaker response. This is not a reason to decline anyone, but it is a reason to discuss reducing the dose beforehand where that can be done safely. Lamotrigine may dampen the response as well. MAOIs require careful attention to blood pressure. Certain stimulants add to the cardiovascular load.

The medication most worth naming is the one people forget: anything taken for high blood pressure, because whether you are actually taking it changes my answer to the first question in this article.

Pregnancy, sleep apnea, liver disease

Ketamine is not used in pregnancy, and safety during breastfeeding is not established. Untreated obstructive sleep apnea raises the risk of airway problems under sedation and needs to be addressed first. Severe liver impairment matters because ketamine is metabolized hepatically, and significant disease changes how the drug clears.

Reasons that are not medical

Some of the people I decline are medically cleared and still not good candidates, and this is the category clinics rarely discuss.

Ketamine treats depression. It does not resolve grief, a bad marriage, financial collapse, or a job that is destroying someone. When I hear a description of circumstances rather than symptoms, the honest recommendation is therapy, not an infusion.

It also is not a first line treatment. It is for people who have tried standard approaches and not gotten better, and someone who has been on one antidepressant for five weeks has not reached that point.

Practical requirements matter as well. You cannot drive yourself home, you need someone available for the rest of that day, and you need to be able to commit to a series rather than a single visit. A patient who can only manage one appointment is unlikely to see the benefit the series is designed to produce.

Finally, expectations. Ketamine works quickly for many people and not at all for some, and anyone arriving certain it will fix everything is set up for a hard landing. I would rather say that at the consultation than after the fourth infusion.

What I suggest when the answer is no

Rarely nothing. Depending on what ruled ketamine out, esketamine nasal spray is sometimes appropriate where IV infusion is not, and it is more often covered by insurance. Some patients are better served by medication adjustment, by TMS, or by addressing a thyroid, sleep, or hormonal issue nobody had checked. Others need the underlying diagnosis looked at again.

The consultation is worth having even if the answer turns out to be no, because you leave with a clearer sense of why and what to do instead. If you want to know whether this treatment is a reasonable fit for you, contact us to arrange an evaluation, or read more about the conditions we work with and how our approach is structured.