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Background Perphenazine is a treatment option in postoperative nausea and vomiting (PONV) prophylaxis. Chronic administration and high dose are known to cause extrapyramidal system (EPS) dysfunction at a frequency of 8%, but the incidence of acute EPS after a single 4 or 8 mg dose is unknown. Objective A retrospective analysis of patient medication billing data and departmental quality records was performed (January 2001 – 10 July 2012) to identify patients who experienced EPS dysfunction after oral perphenazine. Design Retrospective analysis. Setting Surgical outpatients presenting to any one of ten hospitals in the area of Pittsburgh, PA, USA. Patients, other participants Overall, 45,766 patients received 4 or 8 mg of perphenazine before same-day surgery. Main Outcome Measures EPS dysfunction was defined as acute dystonia, akathisia, or pseudoparkinsonism. Records were reviewed to determine the (i) likely number of reactions to perphenazine, (ii) nature of these reactions, and (iii) impact on patient care. Results There were four “likely” cases of EPS dysfunction, and two “possible” cases. Five reported events were consistent with akathisia, with the sixth being a dystonic reaction. All six patients had resolution of symptoms, with five receiving intravenous diphenhydramine for treatment. The incidence of EPS dysfunction was 1.3 events per 10,000 patients (95% CI: 0.4, 3.0, based on 6 events). All patients who experienced reactions preoperatively were able to proceed to surgery without complications or delay. One patient required unplanned admission and 3-hour observation due to sedation from diphenhydramine. The incidence of EPS dysfunction after oral perphenazine is low. Reactions that did occur were mild and easily treated. Conclusions Given the infrequent side-effects, this single, low-dose of perphenazine should be encouraged as a low-risk adjunct to any multimodal PONV prophylaxis regimen, based on the selection criteria described.

Background We tested the hypothesis that patients who continued buprenorphine postoperatively experience postoperative respiratory depression less frequently than those who discontinued buprenorphine. Methods This is a retrospective cohort study of patients who were on buprenorphine preoperatively. The primary outcome was postoperative respiratory depression as defined by respiratory rate < 10/minute, oxygen saturation (SpO2) < 90%, or requirement of naloxone for 48 h postoperatively. The secondary outcome was the composite of postoperative respiratory complications. The associations between postoperative buprenorphine continuation and respiratory depression and respiratory complications were estimated using separate multivariable logistic regression models, including demographic, intraoperative characteristics, and preoperative buprenorphine dose as covariates. Results Postoperative buprenorphine continuation was not associated with postoperative respiratory depression (adjusted odds ratio (OR), 1.11, 95% confidence interval (CI), 0.61 to 1.99, P=0.72). In subanalysis stratified by the preoperative buprenorphine dose, buprenorphine continuation was not associated with postoperative respiratory depression either when preoperative buprenorphine dose was high (≥16 mg daily) or low (<16 mg daily). Postoperative buprenorphine continuation was associated with lower incidence of postoperative respiratory complications (adjusted OR, 0.43, 95% CI, 0.21 to 0.86, P=0.02). Conclusions Continuing buprenorphine was not associated with respiratory depression, but it was associated with a lower incidence of respiratory complications.

Objectives: Buprenorphine is a partial agonist at mu-opioid receptors and competes for these receptors with other opioids in vitro. Whether patients on buprenorphine maintenance require high doses of opioid analgesics to attain adequate postoperative pain control has not been determined. We evaluated differences in acute postoperative opioid consumption and pain burden between patients taking buprenorphine and those taking methadone preoperatively. Materials and Methods:A retrospective review of medical records of 928 patients, of whom 195 were on buprenorphine and 733 were on methadone preoperatively, was performed. Among methadone and buprenorphine patients, 615 and 89, respectively, continued to receive the medications postoperatively. Buprenorphine patients were compared with methadone patients for the first 48 hours postoperatively with regard to acute opioid dose requirements (morphine milligram equivalents [MME] above their baseline buprenorphine and methadone doses) and time-weighted average (TWA) pain scores (using targeted maximum likelihood estimation).Results: Opioid dose requirements for 48 hours postoperatively were 150 (22 to 297) (median [interquartile range]) and 220 [90 to 360] MME for buprenorphine and methadone patients, respectively. Preoperative buprenorphine was associated with a 59.9% lower postoperative MME (95% confidence interval: 46.6%-69.8%, P < 0.0001) compared with methadone. Postoperative TWA pain scores for the first 48 hours were 5.0 ± 2.7 (mean ± SD), and 5.4 ± 2.3 for buprenorphine and methadone patients, respectively. Preoperative buprenorphine was associated with a 0.37-point lower TWA pain score (95% confidence interval: 0.14-0.61, P = 0.002) compared with methadone.Discussion: Preoperative buprenorphine use was associated with > 50% reduction in postoperative opioid dose requirement and a statistically significant, though clinically unimportant, reduction in acute pain burden in comparison to methadone. The study is limited by several important factors such as the exclusion of patients requiring intravenous patient-controlled analgesia, small number of patients were on higher dose of buprenorphine, and a large percentage of methadone patients were not on a stable dose of methadone yet.