This is an outpatient randomized within subject placebo-controlled human laboratory investigation of analgesia (as assessed with quantitative sensory testing; QST) from ketamine alone and in combination with hydromorphone in buprenorphine maintained participants. The goals of this project are to characterize the analgesic, subjective, and physiologic effects of ketamine combined with hydromorphone in patients on buprenorphine maintenance for opioid use disorder.
Eligible participants will have 8 sessions where they will receive two IM injections.The dose of ketamine will be manipulated (0 mg/kg to 0.4 mg/kg) across sessions. The dose of hydromorphone will either be 0 mg or 8 mg. Therefore, participants will be exposed to ascending doses of ketamine with and without hydromorphone. Order of study medications will be randomized for each participant by an un-blinded statistician and transmitted securely to study pharmacist in charge of medication administration. This study will provide unique information on optimal hydromorphone-ketamine dosing strategies for acute pain management. in buprenorphine maintained patients. Each session will take place 17 hours after the last buprenorphine dose (trough levels) to control for time since last dose. Sessions will be held on a dedicated unit for human subjects clinical research at Zuckerberg San Francisco General and include two IM injections of study medication given 15 minutes apart by blinded nursing staff. Study sessions will each last approximately 5 hours. Sessions will take place 1-2x weekly and must be separated by at least 72 hours to allow for drug wash-out. QST outcomes will be measured at baseline, as well as 15, 75, 135, and 195 minutes after injection #2 for each session. In addition, abuse liability outcomes will be measured at baseline (if required) and at 15, 75, 135, and 195 minutes after injection #2 for each session. Blood will be drawn to evaluate baseline buprenorphine /norbuprenorphine levels. Then, PK analyses will be done for ketamine, norketamine and hydromorphone. Blood will be drawn at baseline as well as 15, 75, 135, and 195 minutes after injection #2. Primary outcome will be analgesia as assessed by QST. The use of various QST measures which assess acute anti-nociception as well as central modification of pain processing will allow us to evaluate whether overall analgesia results from blocking of nociceptor signaling and/or changes to central pain facilitation to better understand the mechanism of ketamine-hydromorphone combinations.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
1
Zuckerberg San Francisco General Hospital
San Francisco, California, United States
peak change in cold pressor tolerance
The amount of time (seconds) a participant can keep hand in cold water bath before pain becomes unbearable. The change will be the highest value after study medications have been administered subtracted from the session baseline.
Time frame: 1 day per session
peak change in cold pressor threshold
The time (seconds) at which pain first develops after placing hand in cold water bath. The change will be the highest value after study medications have been administered subtracted from the session baseline.
Time frame: 1 day per session
peak change in conditioned pain modulation (CPM)
Responses to a brief pressure pain stimulus are evaluated alone and then re-assessed during application of a tonic noxious stimulus (hand in water bath) using validated procedures. The peak change in CPM outcome will be a difference in differences score: the largest value of CPM after study medications have been administered subtracted from CPM at baseline
Time frame: 1 day per session
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