Study Finds Lower Dose of Ketamine Equally Effective in Reducing Pain

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Reducing the standard dose of IV-administered ketamine in half is as effective as the larger, standard dose in reducing pain in adults with acute pain, according to a study published in the journal Academic Emergency Medicine.

Ketamine is known to provide pain relief comparable to opioid medications, which are highly addictive. For the current study, Shannon Lovett, MD, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois, and colleagues studied 98 patients, aged 18 to 59 years, who presented to the emergency department with acute, moderate to severe pain.

Patients were randomised prospectively to receive either 0.15 mg/kg or 0.30 mg/kg of ketamine. Patients and providers were blinded to dose, with the primary outcome of pain measured on the 11-point numerical rating scale (NRS) at 30 minutes.

At 15 minutes, the high dose group had a greater decrease in pain on the NRS but more adverse events. At 30 minutes, adverse events and pain were similar. Overall, patients generally reported that they would take ketamine again for pain — 75.6% in the low-dose group and 61.7% in the high-dose group.

“We challenged the conventional ketamine dose used to treat pain,” said Dr. Lovett. “Our study should help demonstrate that a lower dose is sufficient to treat pain.”

The study did not find a significant reduction in side effects from the lower dose.

“As we continue with our research, we hope to find data that supports diminished side effects with the lower dose of ketamine with equal efficacy in treating pain,” said senior author Megan A. Rech, MD, Loyola University Medical Center.