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No Lasting Side Effects With Single Infusion of Low-Dose Ketamine

December 02, 2019

A single, low-dose infusion of ketamine produced no significant long-lasting side effects over 3 months of follow-up in patients with treatment-resistant depression, according to a study published online in the Journal of Affective Disorders.

The study, conducted by researchers at the National Institute of Mental Health (NIMH), Bethesda, Maryland, did identify several brief side effects of a single low dose, but most resolved completely within hours of ketamine infusion.

“The most common short-term side effect was feeling strange or loopy,” said NIMH researcher Elia Acevedo-Diaz, MD. “Most side effects peaked within an hour of ketamine administration and were gone within 2 hours. We did not see any serious, drug-related adverse events or increased ketamine cravings with a single administration.”

Best Practices for Administering Esketamine

Dr. Acevedo-Diaz and colleagues evaluated data from 163 patients with major depressive disorder or bipolar disorder and 25 healthy controls from 5 placebo-controlled trials. Patient assessment included both active and structured surveillance of emerging side effects via clinician interviews and standard rating scales. Potential side effects screened for included dissociative symptoms as well as headaches, dizziness, and sleepiness.

Out of 120 potential side effects, 34 were significantly linked with a single, subanesthetic dose of intravenous ketamine, the study found. Eight side effects occurred in at least half of participants: feeling strange, weird, or bizarre; feeling spacey; feeling woozy/loopy; dissociation; floating; visual distortions; difficulty speaking; and numbness. All resolved within 4 hours.

The study found no serious adverse events, cravings, propensity for recreational use, or significant cognitive or memory deficits over a 3-month follow-up period.

—Jolynn Tumolo


Acevedo-Diaz EE, Cavanaugh GW, Greenstein D, et al. Comprehensive assessment of side effects associated with a single dose of ketamine in treatment-resistant depression. Journal of Affective Disorders. 2019 November 10;[Epub ahead of print].

Side effects mild, brief with single antidepressant dose of intravenous ketamine [press release]. Bethesda, Maryland: National Institute of Mental Health; November 18, 2019.

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