Ketamine Use in Workers’ Compensation: Yay or Nay?

Medicare Set-Aside Blog, Rx/Pharmacy on November 3, 2016 | Posted by Abidemi Oyebode, R.Ph., MBA - Clinical Pharmacist

Ketamine is a dissociative anesthetic approved by the FDA in 1970 to induce and maintain general anesthesia.  It is considered a dissociative drug because it distorts perceptions as well as produces feelings of detachment.  Ketamine is a potent open channel N-methyl-D-aspartate (NMDA)-receptor antagonist.  NMDA receptor excitation results in an influx of calcium into the cell resulting in hyper-excitability.  Clinically, this hyper-excitability presents as allodynia and hyperalgesia (increased sensitivity to pain).  Ketamine, being an NMDA receptor antagonist, prevents the central nervous system from receiving or processing any sensory input leading to anesthesia, analgesia, and amnesia.

Ketamine is FDA approved for use as the sole anesthetic agent for procedures that do not require relaxation of skeletal muscles. Additionally, it is approved for use prior to or in addition to use of other anesthetic agents.  All other uses, particularly use on an outpatient basis, would be considered off-label, non-Medicare covered uses.   Off-label use of ketamine is not approved by the FDA, though there is literature to suggest it could be beneficial in the treatment for certain conditions.  The most common use of ketamine, seen in workers’ compensation patients, is use in transdermal compounded preparations for the treatment of pain, especially neuropathic pain. In these instances, ketamine is typically used in conjunction with other agents such as lidocaine and the preparation is applied directly to the skin. Despite its frequent use, there are very few studies regarding the efficacy of these preparations.  Furthermore, the question of patient safety can also not be overlooked. There is no standardization for compounded transdermal ketamine preparations and even less evidence to show which transdermal drug delivery system provides the best clinical response and safety profile for patients.   One cannot ignore the fact that ketamine is a schedule III controlled substance with high potential for abuse.  Abusers inject, inhale and smoke ketamine because of its hallucinogenic and dissociative high among other side effects.  Ketamine’s sympathomimetic side effect profile and liver enzymes elevation, also cannot be ignored and bring into question its safety in outpatient use.  Off label use of ketamine in a transdermal preparation is not FDA-approved, is not covered by Medicare and may be dangerous.  Further research and debate regarding off-label use of ketamine is an utmost priority before endorsing its use in transdermal preparations.

To request a copy of our white paper, Ketamine Use in Workers’ Compensation, please follow the link here.