Use of electronic health data to identify patients with moderate-to-severe osteoarthritis of the hip and/or knee and inadequate response to pain medications

BACKGROUND

No algorithms exist to identify important osteoarthritis (OA) patient subgroups (i.e., moderate-to-severe disease, inadequate response to pain treatments) in electronic healthcare data, possibly due to the complexity in defining these characteristics as well as the lack of relevant measures in these data sources. We developed and validated algorithms intended for use with claims and/or electronic medical records (EMR) to identify these patient subgroups.

METHODS

We obtained claims, EMR, and chart data from two integrated delivery networks. Chart data were used to identify the presence or absence of the three relevant OA-related characteristics (OA of the hip and/or knee, moderate-to-severe disease, inadequate/intolerable response to at least two pain-related medications); the resulting classification served as the benchmark for algorithm validation. We developed two sets of case-identification algorithms: one based on a literature review and clinical input (predefined algorithms), and another using machine learning (ML) methods (logistic regression, classification and regression tree, random forest). Patient classifications based on these algorithms were compared and validated against the chart data.

RESULTS

We sampled and analyzed 571 adult patients, of whom 519 had OA of hip and/or knee, 489 had moderate-to-severe OA, and 431 had inadequate response to at least two pain medications. Individual predefined algorithms had high positive predictive values (all PPVs ≥ 0.83) for identifying each of these OA characteristics, but low negative predictive values (all NPVs between 0.16-0.54) and sometimes low sensitivity; their sensitivity and specificity for identifying patients with all three characteristics was 0.95 and 0.26, respectively (NPV 0.65, PPV 0.78, accuracy 0.77). ML-derived algorithms performed better in identifying this patient subgroup (range: sensitivity 0.77-0.86, specificity 0.66-0.75, PPV 0.88-0.92, NPV 0.47-0.62, accuracy 0.75-0.83).

CONCLUSIONS

Predefined algorithms adequately identified OA characteristics of interest, but more sophisticated ML-based methods better differentiated between levels of disease severity and identified patients with inadequate response to analgesics. The ML methods performed well, yielding high PPV, NPV, sensitivity, specificity, and accuracy using either claims or EMR data. Use of these algorithms may expand the ability of real-world data to address questions of interest in this underserved patient population.

Dual-Acting Peripherally Restricted Delta/Kappa Opioid (CAV1001) Produces Antinociception in Animal Models of Sub-Acute and Chronic Pain

Background

The development of highly efficacious alternatives to mu-opioid analgesics represents an urgent unmet medical and public health need. In the presence of inflammation both delta- and kappa-opioid agonists, acting on peripheral sensory neurons, mediate analgesia. The dual-acting, peripherally restricted kappa/delta-opioid agonist, CAV1001, was tested in four rodent pain models.

Methods

Experiment 1 – Formalin testing in mice. Three doses (1–10 mg/kg) of CAV1001 or ICI204448 at 30 minutes were tested after formalin injection. Spontaneous nocifensive responses were video recorded. Experiment 2 – Complete Freund’s Adjuvant (CFA)-induced arthritis. CFA was injected into the ankle joint of rats. Joint compression thresholds (JCT) were measured. CAV1001 was compared to celecoxib. Experiment 3 – Spinal nerve ligation (SNL) in rats. Paw compression thresholds (PCT) were measured. CAV1001 was compared to gabapentin. Experiment 4 – MMRT-1 bone cancer implantation into the rat tibia. Weight-bearing was assessed. CAV1001 was compared to morphine.

Results

In Phase 2 of the formalin model, CAV1001 (1 mg/kg) significantly reduced pain behaviors to a degree comparable to the peripherally restricted kappa-opioid agonist, ICI204448 (10 mg/kg). CAV1001 (10 mg/kg) effectively eliminated pain behaviors associated with phase 2. In the CFA-induced arthritis model, a significant increase in JCTs, similar to the comparator celecoxib, was observed with CAV1001 at 1 mg/kg at 2 hours; CAV1001 (10 mg/kg) was effective at 1 hour. In the SNL model, both the comparator gabapentin and CAV1001 (5 mg/kg) significantly reduced PCT at 2 hours, but at 4 hours, the CAV1001 thresholds improved to baseline. CAV1001 10 mg/kg significantly improved weight bearing at 4-hour post-dosing compared to baseline following MMRT-1 implantation.

Conclusion

CAV1001 demonstrated efficacy in several different preclinical pain models. Time- and dose-dependent differences in the efficacy of CAV1001 amongst these rodent pain models parallel the degree of underlying inflammation.

Ease-of-care from the physical therapists’ perspective comparing fentanyl iontophoretic transdermal system versus morphine intravenous patient-controlled analgesia in postoperative pain management

Aim: To compare the ease-of-care (EOC) examining time efficiency, convenience and satisfaction of fentanyl iontophoretic transdermal system ([ITS] IONSYS®) and morphine intravenous patient-controlled analgesia (iv. PCA) in postoperative pain management using a validated physical therapist (PT) EOC questionnaire. Materials & methods: This meta-analysis assessed EOC of fentanyl ITS versus morphine iv. PCA using data from two randomized, active-comparator studies (fentanyl ITS: n = 720 and morphine iv. PCA: n = 739) which used the PT EOC questionnaire (22 items grouped into three subscales; time efficiency, convenience and satisfaction). Each item was scored on a 6-point Likert scale. For time efficiency, PT whose average scores were ≤2 on all items of the time efficiency and convenience subscales or ≥4 on both satisfaction items were considered responders. Results: There were EOC questionnaires from 264 (fentanyl ITS) and 254 (morphine iv. PCA) PTs. There were significantly greater proportions of PTs classified as responders for fentanyl ITS than morphine iv. PCA for overall EOC (81.0 vs 55.7%, respectively), time efficiency (83.1 vs 59.5%, respectively), convenience (87.4 vs 72.0%, respectively) and satisfaction (51.9 vs 30.0%, respectively), all p < 0.0001. Conclusion: In this meta-analysis, fentanyl ITS is associated with a superior EOC profile (overall, time efficiency, convenience and satisfaction) from the PTs’ perspective when compared with morphine iv. PCA.

Patient considerations in the use of transdermal iontophoretic fentanyl for acute postoperative pain

Opioids are commonly used in the management of moderate-to-severe postoperative pain. Patient-controlled analgesic techniques are recognized as preferred administration methods. Previously, research has focused on intravenously administered opioids via a programmable pump. More recently, an iontophoretic transdermal system (ITS), which is patient controlled, has been developed. The focus of this review is on pain management using the fentanyl ITS during the 24-72-hour time period immediately following surgery. Fentanyl ITS offers a needle-free alternative to traditional intravenous (IV) patient-controlled analgesia (PCA) system that is as effective and safe as IV PCA. This system is easy to use for both patients and nurses. The use of fentanyl ITS is generally associated with a better ease-of-care profile, including a greater ease of mobility, from a patients' perspective when compared with morphine IV PCA.

Fentanyl iontophoretic transdermal system versus morphine intravenous patient-controlled analgesia for pain management following orthopedic surgery: A pooled analysis of randomized, controlled trials

OBJECTIVE

To compare the efficacy and safety of patient-controlled pain management following orthopedic surgery using either fentanyl iontophoretic transdermal system (ITS) or morphine intravenous (i.v.) patient-controlled analgesia (PCA).

SETTING

Acute Care Hospital.

PATIENTS

Three-open-label, multicenter, randomized, active-controlled, parallel-group phase 3B studies (N = 2095) were conducted that compared fentanyl ITS with morphine i.v. PCA for postoperative pain in hospitalized postoperative patients. A subgroup of orthopedic surgery patients (N = 1,216) was pooled for this analysis; of which 819 completed treatment.

INTERVENTIONS

A total of 590 patients received fentanyl ITS (40 µg/dose) and 626 patients received morphine i.v. PCA (1 mg/dose) for up to 72 hours.

MAIN OUTCOME MEASURES

Efficacy measures included the patient global assessment (PGA) and the investigator global assessment (IGA) of the method of pain control.

RESULTS

Patients had a mean age of about 60 years, were predominantly Caucasian (90.5 percent), and the majority underwent hip replacement (80.3 percent). There were more patients treated with fentanyl ITS who rated their pain control method as "excellent" compared to morphine i.v. PCA at 24 hours postsurgery (44.8 percent vs 33.0 percent, respectively; p < 0.001), 48 hours (37.5 percent vs 25.3 percent, respectively; p < 0.001), and at the last assessment (54.3 percent vs 39.6 percent, respectively; p < 0.001). There were more investigators who rated treatment with fentanyl ITS as "excellent" compared to morphine i.v. PCA at the last assessment (57.4 percent vs 36.9 percent, respectively; p < 0.001).

CONCLUSIONS

Following orthopedic surgery, patients and investigators more frequently reported global assessment of pain control as "excellent" on the PGA and IGA assessments with fentanyl ITS than with morphine i.v. PCA.

Noradrenergic reuptake inhibition in the treatment of pain

INTRODUCTION

Noradrenergic reuptake inhibitors can be effective analgesics, finding application in a wide variety of clinical pain settings. Due to a shift toward noradrenergic-mediated pain pathways following nerve injury, they are particularly well suited to the treatment of neuropathic pain. This phenotypic shift makes neuropathic pain difficult to control with opioids alone; some noradrenergic reuptake inhibitors have demonstrated synergy with opioids. Agents currently in early clinical trials are discussed and include both novel delivery of old drugs and the development of new drugs.

AREAS COVERED

This review was limited to noradrenergic reuptake inhibitors and analgesia. Literature search included the terms adrenergic, noradrenergic, reuptake, inhibitors, analgesia, NET, norepinephrine transporter, and pain using Medline, Google scholar, Web of Knowledge, www.clinicaltrials.gov, and Pharmaprojects (Informa UK Ltd. 2012).

EXPERT OPINION

Topical drug delivery and the use of combinations of agents both topically and systemically are under active investigation. The intrathecal delivery of noradrenergic reuptake inhibitors, allowing delivery directly to the central nervous system thus limiting systemic exposure, represents an exciting avenue of investigation. Gaps in current knowledge have complicated the development of prophylactic therapies for susceptible individuals or preemptive intervention. Disease-modifying agents and selective inhibitors would facilitate these treatment strategies.

Perioperative use of etoricoxib reduces pain and opioid side-effects after total abdominal hysterectomy: a double-blind, randomized, placebo-controlled phase III study

OBJECTIVE

To evaluate the effects of two different doses of etoricoxib delivered perioperatively compared with placebo and standard pain management on pain at rest, pain with mobilization, and use of additional morphine/opioids postoperatively.

RESEARCH DESIGN AND METHODS

In this double-blind, placebo-controlled, randomized clinical trial, we evaluated postoperative pain following total abdominal hysterectomy over 5 days in patients receiving placebo or etoricoxib administered 90 min prior to surgery and continuing postoperatively. Patients were randomly assigned to receive either placebo (n = 144), etoricoxib 90 mg/day (n = 142), or etoricoxib 120 mg/day (n = 144). Average Pain Intensity at Rest over days 1-3 (0- to 10-point numerical rating scale [NRS]) was the primary efficacy endpoint. Secondary endpoints included Average Pain Intensity upon Sitting, Standing, and Walking over days 1-3 (0- to 10-point NRS) as well as Average Total Daily Dose of Morphine over days 1-3.

CLINICAL TRIAL REGISTRATION

This trial is registered on www.clinicaltrials.gov (NCT00788710).

RESULTS

The least squares (LS) means (95% CI) for the primary endpoint were 3.26 (2.96, 3.55); 2.46 (2.16, 2.76); and 2.40 (2.11, 2.69) for placebo, etoricoxib 90 mg, and etoricoxib 120 mg, respectively, significantly different for both etoricoxib doses versus placebo (p < 0.001). Patients on etoricoxib 90 mg and 120 mg required ~30% less morphine per day than those on placebo (p < 0.001), which led to more rapid bowel recovery in the active treatment groups by ~10 hours vs. placebo. A greater proportion of patients on etoricoxib (10-30% greater than placebo) achieved mild levels of pain with movement, defined as pain ≤3/10.

LIMITATIONS

A key limitation for this study was that movement-evoked pain measurements were not designated as primary endpoints.

CONCLUSION

In patients undergoing total abdominal hysterectomy, etoricoxib 90 mg and 120 mg dosed preoperatively and then continued postoperatively significantly reduces both resting and movement-related pain, as well as reduced opioid (morphine) consumption that led to more rapid bowel recovery.

The effect of initial local anesthetic dose with continuous interscalene analgesia on postoperative pain and diaphragmatic function in patients undergoing arthroscopic shoulder surgery: a double-blind, randomized controlled trial

Background

Interscalene block (ISB) is commonly performed using 20-40 mL of local anesthetic. Spread to adjacent structures and consequent adverse effects including paralysis of the ipsilateral hemidiaphragm are frequent. Pain ratings, analgesic requirements, adverse events, satisfaction, function and diaphragmatic excursion were compared following interscalene block (ISB) with reduced initial bolus volumes.

Methods

Subjects undergoing arthroscopic rotator cuff repair were randomized to receive 5, 10, or 20 mL ropivacaine 0.75% for ISB in a double-blind fashion (N = 36). Continuous infusion with ropivacaine 0.2% was maintained for 48 h. Pain and diaphragmatic excursion were assessed before block and in the recovery unit.

Results

Pain ratings in the recovery room were generally less than 4 (0-10 NRS) for all treatment groups, but a statistically significant difference was noted between the 5 and 20 mL groups (NRS: 2.67 vs. 0.62 respectively; p = 0.04). Pain ratings and supplemental analgesic use were similar among the groups at 24 h, 48 h and 12 weeks. There were no differences in the quality of block for surgical anesthesia. Dyspnea was significantly greater in the 20 mL group (p = 0.041). Subjects with dyspnea had significant diaphragmatic impairment more frequently (Relative risk: 2.5; 95%CI: 1.3-4.8; p = 0.042). Increased contralateral diaphragmatic motion was measured in 29 of the 36 subjects. Physical shoulder function at 12 weeks improved over baseline in all groups (baseline mean SST: 6.3, SEM: 0.6; 95%CI: 5.1-7.5; 12 week mean SST: 8.2, SEM: 0.46; 95%CI: 7.3-9.2; p = 0.0035).

Conclusions

ISB provided reliable surgical analgesia with 5 mL, 10 mL or 20 mL ropivacaine (0.75%). The 20 mL volume was associated with increased complaints of dyspnea. The 5 mL volume was associated with statistically higher pain scores in the immediate postoperative period. Lower volumes resulted in a reduced incidence of dyspnea compared to 20 mL, however diaphragmatic impairment was not eliminated. Compensatory increases in contralateral diaphragmatic movement may explain tolerance for ipsilateral paresis.

Trial Registration

clinicaltrials.gov. identifier: NCT00672100

Capsaicin instillation for postoperative pain following total knee arthroplasty: a preliminary report of a randomized, double-blind, parallel-group, placebo-controlled, multicentre trial

BACKGROUND

Pain following total knee arthroplasty (TKA) interferes with rehabilitation. Capsaicin applied in high concentration to nociceptors can cause relatively selective C-fibre desensitization for a period of weeks to months. Resultant long-lasting analgesia might facilitate rehabilitation.

OBJECTIVE

The objective of this study was to determine if direct instillation of a high-concentration capsaicin preparation into the wound following TKA would provide pain relief, improve physical functioning and rehabilitation, and reduce opioid requirements.

METHODS

This was a randomized, double-blind, parallel-group, placebo-controlled, multicentre, phase II trial carried out in a teaching hospital system. Non-opioid-tolerant males or females aged 18-85 years with a body mass index (BMI) ≤45 kg/m2, American Society of Anesthesiologists (ASA) physical status 1-3 and end-stage osteoarthritis who were scheduled for primary unilateral TKA were included. Patients received placebo vehicle or capsaicin 15 mg (Anesiva 4975) by instillation immediately prior to wound closure. Surgery was conducted under spinal anaesthesia and femoral nerve block. Postoperative rescue analgesia consisted of intravenous patient-controlled analgesia with morphine for 24 hours; oral oxycodone was provided thereafter as needed. It was hypothesized prior to data collection that capsaicin instillation would reduce postoperative pain scores and result in improved patient satisfaction and ambulation. The primary outcome was the area under the numerical rating scale (NRS) for pain score-time curve from 4 to 24 hours (AUC(4-24)). NRS for pain scores were obtained every 4 hours for 24 hours then daily with ambulation and physical therapy for 3 days. Function and patient satisfaction were assessed at 14, 28 and 42 days.

RESULTS

Data from 14 patients (seven per group) from a single centre (data were not available from other sites because of sponsor bankruptcy) were available for this preliminary report. AUC(4-24) was not significantly different clinically (placebo 70.3; capsaicin 65.7) in this sample; however, a significant opioid-sparing effect was seen in the capsaicin group despite the fact that patients in this group had higher BMIs. Pain scores tended to be lower in the capsaicin group, despite the fact that patients in this group received significantly less rescue opioid medication. Morphine use from 12-24 hours was lower (capsaicin group mean 13.4 mg; 95% confidence interval [CI] 7.4, 19.5; range 10-21 mg vs placebo group mean 25.9 mg; 95% CI 19.8, 32.0; range 15-36 mg; p = 0.009). Total intravenous and oral opioid in morphine equivalents over 72 hours was also lower with capsaicin compared with placebo (p = 0.03). Active range of motion (ROM) was also significantly improved at day 14 in the capsaicin group compared with the placebo group (p = 0.0014). A higher percentage of patients in the capsaicin group reported being extremely satisfied with their treatment. The only statistically significant difference in treatment-emergent adverse events was for pruritus, which was more frequent in the placebo group (p = 0.03).

CONCLUSION

Despite having higher BMIs, patients in the capsaicin group achieved comparable or better pain scores with significantly less opioid use in the first 3 postoperative days. They also had less pruritus, which may have been a consequence of the opioid-sparing effect. The effects of capsaicin with respect to function, however, appeared to be longer lasting, with improved active ROM reported at 14 days.

Tapentadol in pain management: a μ-opioid receptor agonist and noradrenaline reuptake inhibitor

Several mechanisms can be proposed to explain an apparent synergistic analgesic action between μ-opioid and α(2)-adrenergic receptor agonists. Combining both effects in a single molecule eliminates the potential for drug-drug interactions inherent in multiple drug therapy. Tapentadol is the first US FDA-approved centrally acting analgesic having both μ-opioid receptor agonist and noradrenaline (norepinephrine) reuptake inhibition activity with minimal serotonin reuptake inhibition. This dual mode of action may make tapentadol particularly useful in the treatment of neuropathic pain. Having limited protein binding, no active metabolites and no significant microsomal enzyme induction or inhibition, tapentadol has a limited potential for drug-drug interactions. Clinical trial evidence in acute and chronic non-cancer pain and neuropathic pain supports an opioid-sparing effect that reduces some of the typical opioid-related adverse effects. Specifically, the reduction in treatment-emergent gastrointestinal adverse effects for tapentadol compared with equianalgesic pure μ-opioid receptor agonists results in improved tolerability and adherence to therapy for both the immediate- and extended-release formulations of tapentadol.

Tapentadol immediate-release for acute pain

Tapentadol is a novel opioid agent with a dual mode of analgesic action. The inhibition of norepinephrine combined with moderate opioid agonist activity results in fewer gastrointestinal adverse effects compared with equianalgesic doses of oxycodone. Having no active metabolites and minimal protein binding, tapentadol provides improved tolerability with a lower potential for pharmacokinetic drug-drug interactions or accumulation with impaired renal or hepatic function when compared with oxycodone. Tapentadol immediate-release is currently US FDA approved for moderate-to-severe acute pain in adults.

Aprepitant vs. multimodal prophylaxis in the prevention of nausea and vomiting following extended-release epidural morphine

BACKGROUND

Extended-release epidural morphine (EREM) is an effective option for postoperative analgesia following major orthopedic surgery; however, postoperative nausea/vomiting (PONV) is a recognized limitation. The incidence of PONV following prophylactic aprepitant, a neurokinin-1 antagonist, was compared with prophylactic multimodal antiemetic therapy in patients receiving EREM for postoperative analgesia following unilateral primary total knee arthroplasty (TKA).

METHODS

Prospectively collected quality assurance data were examined with Institutional Review Board approval. A sequential, open-label, active matched case-control study compared PONV following EREM in patients receiving ondansetron and dexamethasone, and either metoclopramide, diphenhydramine, or prochlorperazine every 6 hours for the 48-hour study period, to patients receiving aprepitant 40 mg given as a single oral dose in the preoperative holding area. Cases were matched for procedure (TKA), age, epidural morphine dose, and known major risk factors for PONV (sex, smoking, previous PONV/motion sickness).

RESULTS

Twelve consecutive patients (3 male; 9 female) receiving aprepitant prior to EREM were matched to 12 patients of the same sex of similar age (range 51 to 84 years.) and EREM dose (range 5 to 12.5 mg) receiving the multimodal regime. The incidence of PONV was significantly less for the aprepitant group where 3 of 12 (25%) had PONV compared with 9 of 12 (75%) in the multimodal group (P = 0.039, Fisher's Exact Test; odds ratio = 0.11; 95% CI: 0.018 to 0.706, P = 0.03).

CONCLUSION

While aprepitant significantly reduced the incidence of PONV compared with a multimodal antiemetic regime, used alone it did not eliminate PONV.

Tapentadol immediate release for the relief of moderate-to-severe acute pain

Tapentadol is a novel, centrally acting analgesic with two mechanisms of action: micro-opioid receptor agonism and norepinephrine reuptake inhibition. It has demonstrated broad analgesic efficacy across multiple pain models. This article reviews the clinical development of tapentadol immediate release (IR), including results from Phase II and III clinical trials that evaluated the efficacy and safety of tapentadol IR in patients with moderate-to-severe acute pain. In clinical studies in patients with moderate-to-severe acute postoperative pain, osteoarthritis pain and/or low back pain, tapentadol IR 50, 75 or 100 mg every 4 - 6 h has demonstrated analgesic efficacy similar to that observed with the micro-opioid receptor agonist oxycodone HCl IR 10 or 15 mg every 4 - 6 h. However, at doses providing comparable analgesic efficacy, tapentadol IR has been associated with significantly lower incidences of nausea and/or vomiting and constipation, and a significantly lower rate of treatment discontinuation compared with oxycodone IR. The observed efficacy across different pain models and favorable gastrointestinal tolerability profile associated with tapentadol IR indicate that this novel analgesic is an attractive treatment option for the relief of moderate-to-severe acute pain.

Extended-release epidural morphine (DepoDur): review and safety analysis

Extended-release epidural morphine (EREM) provides effective postoperative analgesia for 48 h following injection. It is administered as a single bolus into the lumbar epidural space, and is indicated for lower abdominal and lower extremity surgery associated with moderate-to-severe pain. While its efficacy has been well documented in randomized controlled trials, the safety and clinically appropriate dosing are less well defined. A meta-analysis approach was used to assess the adverse effects of EREM (n = 801) in comparison with intravenous opioids and standard epidural morphine. EREM 15 mg or greater was associated with a trend towards a higher incidence of hypoventilation (odds ratio: 0.48; 95% confidence interval [CI]: 0.21-1.09; p = 0.081; number-needed-to-treat [NNT] = 14) compared with placebo. The incidence of pruritus was significantly higher for all EREM doses compared with both placebo (p = 0.004) and standard epidural morphine (p = 0.03). Vomiting was also increased with EREM 15 mg or greater compared with placebo (odds ratio: 0.40; 95% CI: 0.18-0.89; p = 0.02; NNT = 5). A multimodal analgesic regime is recommended to permit the use of lower EREM doses, thus reducing the risk for adverse effects including respiratory depression. Prophylactic time-contingent antiemetics are also recommended when EREM is used.

Patient-controlled transdermal iontophoretic fentanyl system as an alternative to intravenous morphine PCA

Patient-controlled analgesia (PCA) with intravenous morphine is commonly used to control moderate-to-severe postoperative pain. The US FDA recently approved a transdermal system for patient-controlled iontophoretic delivery of fentanyl as an alternative treatment. Aside from the route of administration, other differences between these systems may result in differing adverse-effect profiles. This review compares the clinical utility of these two modalities. MEDLINE, Cinahl and Google Scholar searches for clinical trials (1982 through to July 2007) were performed. Search terms included transdermal analgesia, iontophoresis, patient-controlled analgesia, IONSYS™ and E-TRANS®. All trials comparing intravenous morphine PCA with the transdermal iontophoretic fentanyl system (fentanyl ITS) were included. CONSORT diagrams and adverse-event frequencies were available in all cases. Results demonstrated that fentanyl ITS and intravenous PCA morphine are equally effective analgesics for the management of acute postoperative pain. Fentanyl ITS is associated with fewer treatment failures due to adverse events (p = 0.046), less pruritus (p = 0.001) and less somnolence (p = 0.055). Intravenous PCA morphine is associated with fewer treatment failures due to inadequate analgesia (p = 0.001). It was concluded that fentanyl ITS is an equally safe and effective alternative to intravenous PCA morphine. Advantages favoring fentanyl ITS include convenience and ease-of-care.

Fentanyl iontophoretic transdermal system for acute-pain management after orthopedic surgery: a comparative study with morphine intravenous patient-controlled analgesia

BACKGROUND AND OBJECTIVES

The fentanyl HCl iontophoretic transdermal system (ITS) has been demonstrated in clinical trials to be safe and effective for acute-pain management after several types of major surgery. The current study compared the efficacy, safety, and convenience of fentanyl ITS with morphine intravenous patient-controlled analgesia (IV PCA) for acute-pain management after unilateral total-hip replacement (THR).

METHODS

In this multicenter (52 sites), randomized, open-label, active-controlled, phase IIIb study, patients (n = 799) received fentanyl ITS (40 mug fentanyl [10-minute infusion/lockout], up to 6 doses/h) or morphine IV PCA (1-mg morphine bolus [5-minute lockout], up to 10 mg/h) after unilateral THR. The primary efficacy measure was success ratings ("excellent" or "good") on the patient global assessment (PGA) of the method of pain control in the first 24 hours. Pain intensity and adverse events were also assessed.

RESULTS

The PGA success ratings (83.0% v 82.2%; difference = 0.9%; 95% CI: -4.4% to 6.1%) and the mean last pain-intensity scores (3.0 v 3.0; difference = 0.0; 95% CI: -0.33 to 0.33) in the first 24 hours were statistically equivalent between fentanyl ITS and morphine IV PCA groups, respectively. The incidence of adverse events was similar between the groups.

CONCLUSIONS

Results of this study demonstrate fentanyl ITS and a standard regimen of morphine IV PCA were comparable methods of pain control for management of acute postoperative pain after THR, on the basis of the PGA success ratings and pain intensity in the first 24 hours of treatment.

Evaluation of a single-dose, extended-release epidural morphine formulation for pain after knee arthroplasty

BACKGROUND

DepoDur is a single-dose, extended-release epidural morphine formulation designed to provide forty-eight hours of pain relief. The drug offers potential advantages over continuous epidural infusions, particularly in patients being treated with anticoagulation therapy. The purpose of this study was to evaluate the efficacy and safety of single-dose epidural DepoDur for pain control following knee arthroplasty.

METHODS

In this multicenter, randomized, double-blind, parallel-group study, patients were randomized to receive a single-dose of DepoDur (20 or 30 mg) or a sham epidural injection thirty minutes before administration of general or regional anesthesia for knee arthroplasty. At their first request for postoperative analgesia, patients who had received DepoDur were given an intravenous bolus of hydromorphone followed by placebo patient-controlled analgesia. Patients who had received the sham epidural were given an intravenous bolus of morphine followed by patient-controlled analgesia with morphine. Patient ratings of pain intensity at rest and with activity, their rating of overall pain control, and postoperative opioid use were recorded. The ability to tolerate physical therapy, the range of motion of the knee, and the need for physical support were assessed as well. Adverse events and vital signs were recorded.

RESULTS

Of 168 patients randomized to receive the 20-mg injection of DepoDur, the 30-mg injection of DepoDur, or the sham epidural injection, fifty-one, fifty-eight, and fifty-five patients, respectively, were included in the efficacy analysis. Compared with the patients treated with intravenous patient-controlled analgesia with morphine, the patients treated with DepoDur had significantly reduced mean pain-intensity-recall scores during the four to eight, four to twelve, four to twenty-four, and four to thirty-hour postdose intervals (p < 0.05 for all comparisons). The patients treated with DepoDur used approximately a threefold lower amount of postoperative opioids in total, with a significant percentage requiring no supplemental opioids. Adverse events common to all groups were nausea (78%), pyrexia (46%), vomiting (43%), pruritus (43%), and hypotension (36%). Respiratory depression was the most common serious adverse event, with serious respiratory depression observed in four DepoDur-treated patients, who were more than sixty-five years of age.

CONCLUSIONS

With appropriate patient selection and monitoring, perioperative single-dose epidural DepoDur was a safe and effective analgesic alternative to postoperative intravenous patient-controlled analgesia following knee arthroplasty, with younger patients benefiting from the 20-mg dose. Additional studies of 10 to 15-mg doses for older patients are warranted.

Extended-Release Epidural Morphine (DepoDurtm): An Old Drug with a New Profile

The FDA has recently approved a novel formulation for epidural morphine administration that allows a single injection to provide 48 hours of analgesia. This may eliminate the need for an indwelling epidural catheter in some circumstances and therefore be particularly well suited to postoperative situations where anticoagulation is required. Other uses that have been less thoroughly studied should be approached with due caution.

Forty-eight hours of postoperative pain relief after total hip arthroplasty with a novel, extended-release epidural morphine formulation

BACKGROUND

Epidural morphine has proven analgesic efficacy in the postoperative period and is widely used. This study evaluated the efficacy of extended-release epidural morphine (EREM; DepoDur; Endo Pharmaceuticals Inc., Chadds Ford, PA; SkyePharma, Inc., San Diego, CA) in providing pain relief for 48 h after surgery.

METHODS

Patients (n = 200) scheduled to undergo total hip arthroplasty were randomized to receive a single dose of 15, 20, or 25 mg EREM or placebo. After surgery and after asking for pain medication, patients had access to intravenous patient-controlled analgesia fentanyl for breakthrough pain as needed. Postoperative intravenous patient-controlled analgesia fentanyl use, time to first postoperative fentanyl use, pain intensity at rest and with activity, patient and surgeon ratings of pain control, and adverse events were recorded.

RESULTS

All EREM dosages reduced the mean (+/- SD) fentanyl use versus placebo (510 +/- 708 vs. 2,091 +/- 1,803 microg; P < 0.0001) and delayed the median time to first dose of fentanyl (21.3 vs. 3.6 h; P < 0.0001). All EREM groups had significantly improved pain control at rest through 48 h postdose (area under the curve [0-48 h]) compared with placebo (P < 0.0005). More EREM-treated patients rated their pain control as good or very good compared with placebo (at 24 h: 90 vs. 65%, P < 0.0001; at 48 h: 83 vs. 67%, P < 0.05). No supplemental analgesia was needed in 25% of EREM-treated patients and 2% of placebo-treated patients at 48 h (P < 0.05). The safety profile of EREM was consistent with that of other epidurally administered opioid analgesics.

CONCLUSIONS

EREM provided significant postoperative pain relief over a 48-h period after hip surgery, without the need for indwelling epidural catheters.

Outcome Prediction Following Sympathetic Block for Complex Regional Pain Syndrome

Evidence for the efficacy of sympathetic blocks as either diagnostic or therapeutic tools in complex regional pain syndrome (CRPS) remains anecdotal. Systematic evaluation has been confounded by inconsistent terminology, difficulties in objectively quantifying physical findings, and failure to control for co-morbid psychological factors. This study examines the relative contribution of physical and psychometric features as prospective predictors of outcome following sympathetic block in the treatment of CRPS. Twenty patients with CRPS characterized by mechanical allodynia and vasomotor/sudomotor disturbance were treated with sympathetic blocks. Long-term outcome was assessed at > 6 months following the last treatment using a mailed questionnaire. Pain relief and functional improvement were negatively influenced by anxiety (P < 0.001). When the improvement in the initial visual analog for pain (VAS) was 50% or greater following "diagnostic" sympathetic block, the percent improvement was highly correlated with improvement at long-term follow-up (P < 0.001). Higher "sensitivity" scores on the Neuropathic Pain Scale (P < 0.001), C fiber allodynia (P < 0.01) and Adelta-fiber allodynia (P < 0.01) on quantitative sensory testing, and pretreatment reported dynamic mechanical allodynia (P < 0.02) all predicted positive response to initial sympathetic block. While sympathetic blocks can be helpful in the reduction of mechanical allodynia, and thus the facilitation of physical and occupational therapy, ultimate response to a regime that includes medications is not predicted by sympathetic block alone.

Multimodal postoperative pain management

PURPOSE

The mechanisms of persistent postoperative pain, rationale for multimodal pain therapy, and limitations of currently available analgesic agents and administration routes and techniques are described.

SUMMARY

Persistent postoperative pain can cause long-term disability. It is the result of complex neurohormonal effects that can be prevented using preemptive analgesic therapy. Multimodal pain therapy can result in additive or synergistic analgesic effects and minimize adverse drug effects. Limitations of systemic opioid analgesics given by patient-controlled analgesia include adverse effects, a short duration of action, and nocturnal hypoxemia. Limitations of local anesthetics include unwanted motor blockade, which can interfere with postoperative mobilization and rehabilitation efforts. Inadvertent administration of analgesics into subarachnoid, subdural, or vascular spaces is a potential problem with the epidural route. Use of this route may be limited by the perioperative use of prophylactic anticoagulation.

CONCLUSION

Research is needed to identify analgesic agents and administration techniques with greater efficacy and safety than those currently available.

The Numeric Rating Scale for Clinical Pain Measurement: A Ratio Measure?

The Numeric Rating Scale (NRS-11) has been widely used clinically for the assessment of pain. Its use for clinical research is controversial. Reports differ as to whether or not the NRS-11 should be treated as a ratio pain measurement tool. This study compared the NRS-11 to a ratio measure for pain assessment: the visual analog scale (VAS). Simultaneous pain measurements using these 2 scales were compared in clinical situations commonly encountered in a tertiary community hospital. Whereas linear relationships were noted in laboring patients and in postoperative patients with thoracic or abdominal incisions during cough, no such correlations were noted for the same postoperative patients at rest or for postoperative orthopedic patients. The NRS-11 should not be considered to be interchangeable with the VAS. Its use for clinical research should be limited to situations where it has specifically demonstrated linear properties.