With the continued focus the opioid crises, efforts to develop opioid sparing pain regimens continue. The CDC has reported that between 1999 to 2021 nearly 645,000 people died from and opioid overdose from either prescription or illicit use. I, as a physician and orthopedic surgeon, have kept a close interest in ways to treat pain and restore function without introducing prolonged use of medication. A recent pilot study from researchers at HSS offers a new and noteworthy pain regimen utilizing a combination of ketamine and aspirin. The results of the pilot study in 22 men and women between ages 47 – 81 following knee replacement surgery was promising enough to prompt a larger study. 18 of the 22 reported no side effects from an oral regimen which was given every 6 hours post-op until discharge or 72 hours.
Ketamine was discovered as a phencyclidine(PCP) derivative in the mid 1960’s and quickly became known for its anesthetic and dissociative effects. Initial patients described floating and being disconnected from their limbs. The psychedelic effects of the drug also became known leading to abuse and classification of the drug as a class III drug. Interestingly the psychedelic effects also led to research into controlled use of ketamine in psychiatry for mental distress and ultimately to modern uses today for resistant depression.
The value of ketamine for its pain relieving analgesic properties is also still of interest which is perhaps renewed in the opioid sparing pain management era. It had been noted by the early 70’s that dosages below ‘dissociative’ possessed analgesic properties with moderate side effects. The authors from the pilot study used a specially formulated oral ketamine rather than the typical intravenous administration to limit these dissociative properties and in combination with aspirin to further buffer these side effects.
Knee replacement is one the more painful orthopedic procedures. Patients routinely receive nerve blocks and narcotics during hospitalization and are discharged on additional narcotic pills for home. Frequently patients return a month of more post-op still reporting pain enough to use medication. With todays efforts to limit opioids, perhaps the renewed interest in ketamine and novel oral formulations will provide new and noteworthy future treatment options.