Sublingual buprenorphine compared to morphine delivered by a patient-controlled analgesia system as postoperative analgesia after prostatectomy

Benefit-Risk Analysis of Buprenorphine for Pain Management

Health care providers in the United States are facing challenges in selecting appropriate medication for patients with acute and chronic pain in the midst of the current opioid crisis and COVID-19 pandemic. When compared with conventional opioids, the partial µ-opioid receptor agonist buprenorphine has unique pharmacologic properties that may be more desirable for pain management. The formulations of buprenorphine approved by the US Food and Drug Administration for pain management include intravenous injection, transdermal patch, and buccal film. A comparison of efficacy and safety data from studies of buprenorphine and conventional opioids suggests that buprenorphine may be a better-tolerated treatment option for many patients that provides similar or superior analgesia. Our benefit-risk assessment in this narrative review suggests that health care providers should consider that buprenorphine may be an appropriate alternative for pain management over other opioids.

RETRACTED: Sublingual buprenorphine versus intravenous or intramuscular morphine in acute pain: A systematic review and meta-analysis of randomized control trials

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Authors. The authors have provided a clarification stating that the article does not clearly or fully disclose that it better represents a subset of a previously published manuscript in the British Journal of Anaesthesia (White LD, Hodge A, Vlok R, Hurtado G, Eastern K, Melhuish TM. Efficacy and adverse effects of buprenorphine in acute pain management: systematic review and meta-analysis of randomized controlled trials. (Br J Anaesth. 2018;120:668-678). The papers presented in their meta-analysis are a subset of those in their previous review in the British Journal of Anaesthesia, and do not present additional information beyond their previously published work.

Pharmacokinetics of buprenorphine after intravenous and oral transmucosal administration in guinea pigs (Cavia porcellus)

OBJECTIVE To determine pharmacokinetics and sedative effects of buprenorphine after IV and oral transmucosal (OTM) administration in guinea pigs. ANIMALS 14 male guinea pigs (6 adults for preliminary experiment; eight 8 to 11-week-old animals for primary study). PROCEDURES A preliminary experiment was conducted to determine an appropriate buprenorphine dose. In the primary study, buprenorphine (0.2 mg/kg) was administered IV or OTM, and blood samples were obtained. The pH of the oral cavity was measured before OTM administration. Sedation was scored for 6 hours on a scale of 0 to 3 (0 = no sedation and 3 = heavy sedation). After a 7-day washout period, procedures were repeated in a crossover manner. Plasma buprenorphine concentration was quantified, and data were analyzed with a noncompartmental pharmacokinetic approach. RESULTS Mean peak plasma buprenorphine concentrations were 46.7 and 2.4 ng/mL after IV and OTM administration, respectively. Mean time to maximum plasma buprenorphine concentration was 1.5 and 71.2 minutes, and mean terminal half-life was 184.9 and 173.0 minutes for IV and OTM administration, respectively. There was a range of sedation effects (0 to 2) for both routes of administration, which resolved within the 6-hour time frame. CONCLUSIONS AND CLINICAL RELEVANCE On the basis of pharmacokinetic parameters for this study, buprenorphine at 0.2 mg/kg may be administered IV every 7 hours or OTM every 4 hours to maintain a target plasma concentration of 1 ng/mL. Further studies are needed to evaluate administration of multiple doses and sedative effects in guinea pigs with signs of pain.

Optimal pain management for radical prostatectomy surgery: what is the evidence?

BACKGROUND

Increase in the diagnosis of prostate cancer has increased the incidence of radical prostatectomy. However, the literature assessing pain therapy for this procedure has not been systematically evaluated. Thus, optimal pain therapy for patients undergoing radical prostatectomy remains controversial.

METHODS

Medline, Embase, and Cochrane Central Register of Controlled Trials were searched for studies assessing the effects of analgesic and anesthetic interventions on pain after radical prostatectomy. All searches were conducted in October 2012 and updated in June 2015.

RESULTS

Most treatments studied improved pain relief and/or reduced opioid requirements. However, there were significant differences in the study designs and the variables evaluated, precluding quantitative analysis and consensus recommendations.

CONCLUSIONS

This systematic review reveals that there is a lack of evidence to develop an optimal pain management protocol in patients undergoing radical prostatectomy. Most studies assessed unimodal analgesic approaches rather than a multimodal technique. There is a need for more procedure-specific studies comparing pain and analgesic requirements for open and minimally invasive surgical procedures. Finally, while we wait for appropriate procedure specific evidence from publication of adequate studies assessing optimal pain management after radical prostatectomy, we propose a basic analgesic guideline.

Patient controlled opioid analgesia versus non-patient controlled opioid analgesia for postoperative pain

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 4, 2006. Patients may control postoperative pain by self administration of intravenous opioids using devices designed for this purpose (patient controlled analgesia or PCA). A 1992 meta-analysis by Ballantyne et al found a strong patient preference for PCA over non-patient controlled analgesia, but disclosed no differences in analgesic consumption or length of postoperative hospital stay. Although Ballantyne's meta-analysis found that PCA did have a small but statistically significant benefit upon pain intensity, a 2001 review by Walder et al did not find statistically significant differences in pain intensity or pain relief between PCA and groups treated with non-patient controlled analgesia.

OBJECTIVES

To evaluate the efficacy and safety of patient controlled intravenous opioid analgesia (termed PCA in this review) versus non-patient controlled opioid analgesia of as-needed opioid analgesia for postoperative pain relief.

SEARCH METHODS

We ran the search for the previous review in November 2004. For this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 12), MEDLINE (1966 to 28 January 2015), and EMBASE (1980 to 28 January 2015) for randomized controlled trials (RCTs) in any language, and reference lists of reviews and retrieved articles.

SELECTION CRITERIA

We selected RCTs that assessed pain intensity as a primary or secondary outcome. These studies compared PCA without a continuous background infusion with non-patient controlled opioid analgesic regimens. We excluded studies that explicitly stated they involved patients with chronic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, which included demographic variables, type of surgery, interventions, efficacy, and adverse events. We graded each included study for methodological quality by assessing risk of bias and employed the GRADE approach to assess the overall quality of the evidence. We performed meta-analysis of outcomes that included pain intensity assessed by a 0 to 100 visual analog scale (VAS), opioid consumption, patient satisfaction, length of stay, and adverse events.

MAIN RESULTS

Forty-nine studies with 1725 participants receiving PCA and 1687 participants assigned to a control group met the inclusion criteria. The original review included 55 studies with 2023 patients receiving PCA and 1838 patients assigned to a control group. There were fewer included studies in our updated review due to the revised exclusion criteria. For the primary outcome, participants receiving PCA had lower VAS pain intensity scores versus non-patient controlled analgesia over most time intervals, e.g., scores over 0 to 24 hours were nine points lower (95% confidence interval (CI) -13 to -5, moderate quality evidence) and over 0 to 48 hours were 10 points lower (95% CI -12 to -7, low quality evidence). Among the secondary outcomes, participants were more satisfied with PCA (81% versus 61%, P value = 0.002) and consumed higher amounts of opioids than controls (0 to 24 hours, 7 mg more of intravenous morphine equivalents, 95% CI 1 mg to 13 mg). Those receiving PCA had a higher incidence of pruritus (15% versus 8%, P value = 0.01) but had a similar incidence of other adverse events. There was no difference in the length of hospital stay.

AUTHORS' CONCLUSIONS

Since the last version of this review, we have found new studies providing additional information. We reanalyzed the data but the results did not substantially alter any of our previously published conclusions. This review provides moderate to low quality evidence that PCA is an efficacious alternative to non-patient controlled systemic analgesia for postoperative pain control.

In vitro dissolution method for evaluation of buprenorphine in situ gel formulation: a technical note

The purpose of the present study was to develop and characterize an oral controlled release drug delivery system for concomitant administration of diclofenac sodium (DS) and chondroitin sulfate (CS). A hydrophilic matrix-based tablet using different concentrations of hydroxypropylmethylcellulose (HPMC) was developed using wet granulation technique to contain 100 mg of DS and 400 mg of CS. Formulations prepared were evaluated for the release of DS and CS over a period of 9 hours in pH 6.8 phosphate buffer using United States Pharmacopeia (USP) type II dissolution apparatus. Along with usual physical properties, the dynamics of water uptake and erosion degree of tablet were also investigated. The in vitro drug release study revealed that HPMC K100CR at a concentration of 40% of the dosage form weight was able to control the simultaneous release of both DS and CS for 9 hours. The release of DS matched with the marketed CR tablet of DS with similarity factor (f(2)) above 50. Water uptake and erosion study of tablets indicated that swelling followed by erosion could be the mechanism of drug release. The in vitro release data of CS and DS followed Korsmeyer-Peppas and zero-order kinetics, respectively. In conclusion, the in vitro release profile and the mathematical models indicate that release of CS and DS can be effectively controlled from a single tablet using HPMC matrix system.

Patient controlled opioid analgesia versus conventional opioid analgesia for postoperative pain

BACKGROUND

Patients may control postoperative pain by self-administration of intravenous opioids using devices designed for this purpose (patient controlled analgesia or PCA). A 1992 meta-analysis by Ballantyne found a strong patient preference for PCA over conventional analgesia but disclosed no differences in analgesic consumption or length of postoperative hospital stay. Although Ballantyne's meta-analysis found that PCA did have a small but statistically significant benefit upon pain intensity, Walder's review in 2001 did not find a significant differences in pain intensity and pain relief between PCA and conventionally treated groups.

OBJECTIVES

To evaluate the efficacy of PCA versus conventional analgesia (such as a nurse administering an analgesic upon a patient's request) for postoperative pain control.

SEARCH STRATEGY

Randomized controlled trials (RCTs) were identified from the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2004, Issue 3), MEDLINE (1966 to 2004), and EMBASE (1994 to 2004). Additional reports were identified from the reference lists of retrieved papers.

SELECTION CRITERIA

RCTs of PCA versus conventional analgesia that employed pain intensity as a primary or secondary outcome were selected. These trials included RCTs that compared PCA without a continuous background infusion versus conventional parenteral analgesic regimens. Studies that explicitly stated they involved patients with chronic pain were excluded.

DATA COLLECTION AND ANALYSIS

Trials were scored using the Oxford Quality Scale. Meta-analyses were performed of outcomes that included analgesic efficacy assessed by a Visual Analog Scale (VAS), analgesic consumption, patient satisfaction, length of stay and adverse effects. A sufficient number of the retrieved trials reported these parameters to permit meta-analyses.

MAIN RESULTS

Fifty-five studies with 2023 patients receiving PCA and 1838 patients assigned to a control group met inclusion criteria. PCA provided better pain control and greater patient satisfaction than conventional parenteral 'as-needed' analgesia. Patients using PCA consumed higher amounts of opioids than the controls and had a higher incidence of pruritus (itching) but had a similar incidence of other adverse effects. There was no difference in the length of hospital stay.

AUTHORS' CONCLUSIONS

This review provides evidence that PCA is an efficacious alternative to conventional systemic analgesia for postoperative pain control.