22nd Annual Pain Medicine Meeting 2023

Dissociative Event in a Chronic Pain Patient After Use of Topical Ketamine 10% Cream: A Case Report

Rachel Esparza, MD^1,2; Drew Michael S. Donnell, MD, MS²; Alyson M. Engle, MD²

¹Shirley Ryan AbilityLab, Chicago, IL; ²Northwestern University/McGaw Medical Center, Chicago, IL

Introduction

- Ketamine has been used off-label for analgesia at subanesthetic doses in patients with acute and chronic pain.
- may reduce pain
- significantly lower plasma levels ^1-3 ➜ minimal systemic side effects vs. IV/PO

-Side effects of IV ketamine: vivid dreams, dissociative events.

-Central effects, higher systemic plasma levels.³- To our knowledge, there are no documented cases of dissociative events after using topical ketamine.

- We present a case of a patient who experienced a dissociative event seven days after initiating use of topical ketamine 10% compound cream.

Methods

- Reviewed literature on topical ketamine and side effects.
- As the case report is devoid of patient identifiable information, it is exempt from IRB review requirements as per Northwestern University’s policy. Informed consent was obtained.

Case Report

- 60 year old male with PMHx of diffuse chronic pain, SDH s/p emergent decompression (2014), and anxiety.

- No history of hallucinations, schizophrenia, or mood disorder.

-Pain Symptoms: neuropathic pain along the skin of the left side of his head radiating to left neck and anteroposterior shoulder.

-Physical Exam: skin hyperalgesia and allodynia along area of pain.

Day 0: Presented to Pain Clinic for chronic neuropathic pain.

- Refractory to conservative management or other creams.

- Wanted a non-oral, minimally invasive, medication.

Day 1-7: Topical Ketamine Cream Use

- Prescribed topical ketamine 10% cream.

- Applied to left head, neck, and shoulder.

- About 12 grams (<0.5 ounces) per day.

- Total: 60 grams in 7 days.

Day 7: Dissociative Event

- Felt “no connection to [his] body” and “couldn’t feel if he was moving or balancing but he knew [he] was.”

- Stopped use.* Symptoms resolved.

Day 9: IV Ketamine Infusion

Significant relief from topical ketamine.** Wanted to try infusion.

- Rate: 0.5 mg/kg/hr (33.3 mg/hr).

- Stopped after 5 minutes due to severe dissociation.

* Tolerated small amount of cream on the day after event (no side effects). He self-administered due to return of severe pain.
**Despite side effect, he reported significant pain relief. It was the first medication that gave him this level of pain relief.
The compound pharmacy stated that this was the first they had heard of topical ketamine causing dissociative events.

Conclusion

This is a novel account given that current research suggests significantly low likelihood of systemic side effects due to reduced or undetectable plasma levels of ketamine after using topical ketamine.

-Future research need: plasma levels of both ketamine and norketamine (ketamine metabolite) after use of topical ketamine.

-Possible causes:

-Individual differences in systemic absorption (e.g. due to skin penetration as in scleroderma vs. aging skin)

-Individuals’ gene expression profile

-Number of ketamine receptors expressed at cellular level.

-Individuals’ underlying anxiety and anticipation of side effects

Many studies support the use of ketamine for chronic pain, anxiety and depression. Clinicians should be aware of the safety profile, abuse potential, and potential side effects, including dissociative or psychotomimetic effects with topical ketamine.

References

1.Finch PM, Knudsen L, Drummond PD. Reduction of allodynia in patients with complex regional pain syndrome: a double-blind placebo-controlled trial of topical ketamine. Pain. 2009 Nov 1;146(1-2):18-25.

2.Crowley KL, Flores JA, Hughes CN, Iacono RP. Clinical application of ketamine ointment in the treatment of sympathetically maintained pain. International Journal of Pharmaceutical Compounding. 1998 Mar 1;2(2):122-7.

3.Sawynok J. Topical and peripheral ketamine as an analgesic. Anesthesia & analgesia. 2014 Jul 1;119(1):170-8.

Full Case Report Text: https://docs.google.com/document/d/1dfQF4V5vIwCL7wtv4zxi1IvKaKOCUPzqShb7yWMidCE/edit?usp=sharing

Corresponding Author: Rachel Esparza, MD rachel.esparza@northwestern.edu

22nd Annual Pain Medicine Meeting 2023

DISSOCIATIVE EVENT IN A CHRONIC PAIN PATIENT AFTER USE OF TOPICAL KETAMINE 10% CREAM: A CASE REPORT

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