Ketamine Dosing for Adults?

Disch, Jno MD

doi: 10.1097/01.EEM.0000311998.97690.1a
Letter

Akron, OH

Editor:

In response to Dr. James Roberts' recent column (“Rapid Tranquilization of the Violently Agitated Patient: Ketamine and an Update on Haloperidol,” EMN 2007;29[12]:14), I wanted to share my recent experience of attempting to use ketamine. We had an adult mentally retarded patient who didn't like to be examined present to our ED for I&D of a forearm abscess. The care facility gave him Ativan before he came, but his mother said Ativan usually didn't calm him much.

I suggested to my resident that we try a dose of IM ketamine because he tried to hit the nurses when they came near, and I thought getting an IV in him would be tricky. I was thinking one quick IM shot, and we would have sedation and analgesia, and then we could do a quick I&D. He was about 70 kg, so we were thinking he needed about 300 mg to 350 mg of ketamine. Because most of my experience had been with using the drug in children, I checked with our anesthesiologist about the dose. He initially thought it was OK, but admitted he didn't have much experience with it. He later called back and told me he recommended a much lower dose, perhaps 100 mg to 150 mg IM. I thought he was getting a little nervous about his advice and my plans to proceed.

The nurses panicked, decided this was an unsafe medicine and that the dose was too high, and they weren't familiar with it. They thwarted our attempts to use it. It was the end of my shift, so I wasn't looking for any battles with the nurses. They found a way to get an IV, and I think the next attending taking over sedated him with propofol.

Does Dr. Roberts have any thoughts about the dose of ketamine or its use in this situation?

Jno Disch, MD

Akron, OH

© 2008 Lippincott Williams & Wilkins, Inc.