Low Dose Ketamine Effect on Postoperative Narcotic Use Following Third Molar Extractions
Low-dose ketamine has been shown to provide preemptive analgesia. This study examines if the noxious stimuli of third molar extractions negates the preemptive analgesic effect of low-dose ketamine.
Materials and Methods:
Two simultaneous clinical prospective studies were conducted with 34 consecutive healthy patients. The patients were treated for extraction of four third molars by one surgeon. Inclusion criteria consisted of the following: ASA I or II, 18-25 years of age, needing four third molars extracted and no significant drug allergies. Exclusion criteria consisted of the following: other teeth indicated for extraction, chronic or acute infection requiring antibiotics, recent use of NSAIDs, significant cardiac or pulmonary issues, and chronic pain patients. Patients were randomly placed into one of two groups, the control group or the low-dose (LD) ketamine group. Intravenous sedation was provided with fentanyl, versed and propofol in both groups. Ketamine was used in the LD ketamine group at a dosing of 0.15mg/kg. Venous blood samples were taken at the following times: prior to administration of any sedative agents, immediately postoperatively, and at 72hours following extractions. Extraction difficulty was scored using a modified Pell and Gregory classification system by a blinded faculty member using preoperative panorex films. Postoperatively, patients were instructed to document their degree of postoperative pain with the aid of a VAS scale. Documentation of their degree of pain was performed three times a day for the first three days and once per day for the next four. Patients were also asked to record the time of day when analgesics were taken, the type of analgesic and the number of analgesics for the seven day study period. Patients were dispensed the following for the control of postoperative pain; opioids (Lortab 7.5mg/500) and NSAIDS (ibuprofen 600mg) and given appropriate dosing information.
Results:
There was a statistically significant difference in the amount of opioids used between the control group and the low-dose ketamine group. Patients took significantly less opioids in the LD ketamine group during days 2, 3, 4. There were no statistically significant differences regarding patient age, sex or difficulty of extractions between the groups. Even though the amount of NSAIDs and total meds taken were lower in the LD ketamine group no statistical significant was achieved. Also the VAS was lower in the LD ketamine group but no statistically significant difference was evident. Analysis of the pooled platelet suspensions revealed that the administration of ketamine modulated thromboxane levels in a naloxone sensitive manner.
Conclusions
Low-Dose ketamine has a significant preemptive analgesic effect resulting in decreased use of postoperative opioids. The administration of low dose ketamine appears to alter thromboxane levels in a naloxone sensitive manner.
The study is continuing to enroll patients to obtain statistical significance regarding the use of NSAIDs and the total use of postoperative analgesics.