Evidence-informed management of chronic low back pain with nonsteroidal anti-inflammatory drugs, muscle relaxants, and simple analgesics

The Effects of Phenyramidol and Diclofenac Treatment on Fracture Healing in Rats

Background

Fracture healing or nonunion refers to a process in which many factors interact. In this study, we aimed to evaluate the radiological, histological, and biomechanical effects of phenyramidol and diclofenac, which are frequently used to treat post-fracture ture pain worldwide, on fracture healing and nonunion in a rat femur fracture model.

Methods

In this study, 72 male Wistar-Albino rats aged 2-3 months and weighing 250 ± 30 g were divided into 4 main groups. The rats were divided into 12 subgroups according to the early, middle, and late periods. A fracture model was created in rat femurs, and surgical fixation was performed. Postoperative analgesic treatment protocols included phenyramidol, diclofenac, phenyramidol + diclofenac, and the control group. The rats were sacrificed on the fifteenth, thirtieth, and forty-fifth days and were evaluated radiologically, histopathologically, and biomechanically.

Results

Scoring was conducted independently by 2 orthopedists not involved in the study. When the results were analyzed statistically, no statistically significant difference was observed between the fifteenth and thirtieth day radiology score values of the control, diclofenac, phenyramidol, and Phenyramidol + diclofenac groups (p > 0.05), but there was a statistically significant difference (p < 0.05) between the forty-fifth day radiology score values of the control, diclofenac, phenyramidol, and phenyramidol + diclofenac groups.

Conclusions

Our study shows that the use of diclofenac or phenyramidol alone negatively affects postoperative fracture healing. However, this effect was less pronounced in the combined treatment group. Histologic examination revealed that neither treatment had a significant effect on healing. There were statistical differences in biomechanical and radiologic properties between the phenyramidol and diclofenac groups; in particular, the diclofenac group had lower biomechanical properties.

Ultrasound guided lumbar erector spinae block: A case series on a novel technique for the treatment of acute low Back pain

Low back pain is among one of the most common presentations to the emergency department (ED). Regional anesthesia has recently gained traction as an option for analgesia in ED patients, especially in the wake of the opioid epidemic. Data on lumbar application of the ESPB in the setting of acute, refractory low back pain in the ED is scarce. We describe a series of three cases of patients who presented to the ED with severe low back pain refractory to traditional therapy, successfully treated using lumbar ESPB. Lumbar ESPB may be an effective approach to achieving rapid analgesia in patients who present with low back pain who may otherwise be poor candidates for more traditional therapy, such as with opioids or NSAIDs, or who may have refractory pain despite use of these medications.

Different Dosage Regimens of Tanezumab for the Treatment of Chronic Low Back Pain: A Meta-analysis of Randomized Controlled Trials

OBJECTIVE

The aim of this study was to assess the efficacy of different dosage regimens of tanezumab among individuals living with chronic low back pain (CLBP).

METHODS

PubMed, Embase, The Cochrane Library, and other databases were searched from inception until August 2021. Randomized controlled trials investigating the efficacy and safety of tanezumab in individuals with CLBP were included. Data were extracted independently by 2 investigators and assessed the study quality by the Cochrane risk-of-bias tool. The measurements include low back pain intensity and Roland-Morris Disability Questionnaire. The incidence of adverse events and serious adverse events was set to assess the safety of tanezumab for CLBP.

RESULTS AND DISCUSSION

Three high-quality randomized controlled trials with 3414 patients were finally included in our analysis. Tanezumab, respectively, led to a notable decrease compared with placebo in low back pain intensity (mean difference, -0.62; 95% confidence interval [CI], -0.77 to -0.46; P < 0.01) and Roland-Morris Disability Questionnaire (mean difference, -0.64; 95% CI, -0.80 to -0.47; P = 0.01). In addition, no significant difference existed between tanezumab and placebo groups (risk ratio, 1.10; 95% CI, 0.81-1.49; P = 0.55) in the adverse events and (risk ratio, 1.06; 95% CI, 0.34-3.27; P = 0.93) serious adverse events.

CONCLUSIONS

Intravenous and subcutaneous tanezumab injections as treatment for improving CLBP have promising clinical application as its great improvement on all efficacy and its controllable safety issues. Furthermore, intravenous and subcutaneous tanezumab injections were proved to achieve excellent and long-term curative effect on CLBP through our subgroup analysis and comparison.

Exploring the Feasibility of Virtually Delivered Auricular Point Acupressure in Self-Managing Chronic Pain: Qualitative Study

Background

Chronic pain remains highly prevalent. Current pharmacological and non-pharmacological strategies have not adequately managed chronic pain which has contributed to disability and high healthcare costs. With existing challenges in providing adequate pain care and access, we tested vAPA, a virtually delivered, self-management intervention using Auricular Point Acupressure (APA) by mobile app and virtual consultations (telehealth). Our key purpose was to evaluate the feasibility of the vAPA in self-managing chronic pain in preparation for a future randomized controlled trial.

Methods

We conducted a descriptive, qualitative study evaluating our 4-week vAPA intervention among 18 participants. We used directed qualitative content analysis. Results and Conclusion. Participants perceived that vAPA was feasible (acceptable, useable, practical, and beneficial). In addition, the following themes were gathered: better control of pain, less use of pain medications, self-management and motivation in pain, and expectations for pain relief. Refinements were recommended for the app, content, and delivery to improve study interventions. Findings are relevant in moving forward to a future randomized controlled trial and for wider implementation in a pragmatic clinical trial.

Diagnostic Role of Magnetic Resonance Imaging in Low Back Pain Caused by Vertebral Endplate Degeneration

Low back pain (LBP) is a common health issue worldwide with a huge economic burden on healthcare systems. In the United States alone, the cost is estimated to be $100 billion each year. Intervertebral disc degeneration is considered one of the primary causes of LBP. Moreover, the critical role of the vertebral endplates in disc degeneration and LBP is becoming apparent. Endplate abnormalities are closely correlated with disc degeneration and pain in the lumbar spine. Imaging modalities such as plain film radiography, computed tomography, and fluoroscopy are helpful but not very effective in detecting the causes behind LBP. Magnetic resonance imaging (MRI) can be used to acquire high-quality three-dimensional images of the lumbar spine without using ionizing radiation. Therefore, it is increasingly being used to diagnose spinal disorders. However, according to the American College of Radiology, current referral and justification guidelines for MRI are not sufficiently clear to guide clinical practice. This review aimed to evaluate the role of MRI in diagnosing LBP by considering the correlative contributions of vertebral endplates. The findings of the review indicate that MRI allows for fine evaluations of endplate morphology, endplate defects, diffusion and perfusion properties of the endplate, and Modic changes. Changes in these characteristics of the endplate were found to be closely correlated with disc degeneration and LBP. The collective evidence from the literature suggests that MRI may be the imaging modality of choice for patients suffering from LBP. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 3.

Auricular Point Acupressure Smartphone Application to Manage Chronic Musculoskeletal Pain: A Longitudinal, One-Group, Open Pilot Trial

BACKGROUND

Chronic musculoskeletal pain (CMP) is the most common self-reported chronic pain condition. Current treatment for CMP is limited.

METHODS

This was a two-phase study. In Phase 1, three auricular point acupressure (APA)-naïve participants were recruited to explore their experiences of APA and a smartphone app was developed based on their feedback. In Phase 2, a prospective longitudinal study was used to examine the effectiveness of the smartphone app to self-manage CMP.

RESULTS

Phase 1 resulted in the successful development of the APA smartphone app. In Phase 2, after four weeks of APA, participants reported reduced pain intensity (30%), pain interference (35%), and disability (40%), as well as improved physical function (47%). The mean score for the participants' perception of treatment efficacy was 4.94 (SD = 2.08, scale of 0-7) indicating that approximately 70% of participants rated global improvements with noticeable changes. The majority (88%, n = 22) of the participants were satisfied with the treatment: 32% [8] were very satisfied and 56% [n = 14] were somewhat satisfied. The average frequency of pressing APA seeds per day was 2.93 times (SD = 2.27, range 0-10) and 1.60 minutes per time (SD = 2.64, range 0-10); the participants were able to adhere to the suggested pressing time per day, although they only pressed the ear points about 53% of the suggested time.

CONCLUSION

It is feasible for individuals to learn APA from the smartphone app and successfully self-administer APA to manage their pain. Participants found the app useful and were satisfied with the information provided through the app.

A prospective randomized controlled study of auricular point acupressure to manage chronic low back pain in older adults: study protocol

BACKGROUND

Chronic low back pain (cLBP) is a major health problem and the most common pain condition among those aged 60 years or older in the US. Despite the development of pharmacological and nonpharmacological interventions, cLBP outcomes have not improved and disability rates continue to rise. This study aims to test auricular point acupressure (APA) as a non-invasive, nonpharmacological self-management strategy to manage cLBP and to address current shortcomings of cLBP treatment.

METHODS/DESIGN

For this prospective randomized controlled study, participants will be randomly assigned to three groups: (1) APA group (active points related to cLBP), (2) Comparison group-1 (non-active points, unrelated to cLBP), and (3) Comparison group-2 (enhanced educational control, an educational booklet on cLBP will be given and the treatment used by participants for their cLBP will be recorded). The ecological momentary assessment smartphone app will be used to collect real-time cLBP outcomes and adherence to APA practice. Treatment and nonspecific psychological placebo effects will be measured via questionnaires for all participants. This proposed trial will evaluate the APA sustained effects for cLBP at 12-month follow-up. Monthly telephone follow-up will be used to collect study outcomes. Blood will be collected during study visits at baseline, post APA treatment, and follow-up study visits at 1, 3, 6, 9 and 12 months post completion of treatment for a total of seven assessments. Appointments will start between 9 and 11 am to control for circadian variation in cytokine levels.

DISCUSSION

This study is expected to provide vital information on the efficacy, sustainability, and underlying mechanism of APA on cLBP necessary for APA to gain acceptance from both healthcare providers and patients, which would provide a strong impetus for including APA as part of cLBP management in clinical and home settings.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03589703. Registered on 22 May 2018.

The effects of foot reflexology on back pain after coronary angiography: A randomized controlled trial

BACKGROUND AND AIMS

Back pain is among the most common complaints of patients during the first hours after coronary angiography (CA), i.e. when they are restricted to complete bed rest. This study aimed to evaluate the effects of foot reflexology on back pain after CA.

METHODS

This randomized controlled trial was conducted in 2018-2019 on patients hospitalized in the post-angiography unit of Razi hospital, Birjand, Iran. Through convenience sampling, 120 patients were recruited and their demographic characteristics and baseline back pain intensity were assessed immediately after angiography using a demographic questionnaire and a visual analogue scale, respectively. Then, patients were randomly allocated to a control (n = 60) and a reflexology (n = 60) group through block randomization. Patients in the reflexology group received 8-min foot reflexology for each foot (16 min for both feet) while their counterparts in the control group solely received routine post-angiography care services. Back pain assessment was repeated for all participants immediately, two, four, and 6 h after the intervention. Data were analyzed using the SPSS software (v. 16.0).

FINDINGS

Back pain intensity significantly increased after angiography in both groups (P < 0.05). Yet, pain intensity in the reflexology group at all post-intervention measurement time points was significantly less than the control group (P < 0.001).

CONCLUSION

Foot reflexology is effective in significantly reducing back pain after CA.

Analyzing the Influence of Modic Changes on Patients with Lower Back Pain Undergoing Conservative Treatment

Objective

This study aimed to investigate if the presence of Modic changes (MCs) was correlated with lower back pain (LBP) and LBP-related disability in patients who underwent nonsurgical treatment.

Methods

In this study, 129 patients who experienced consecutive LBP and underwent lumbar spine magnetic resonance imaging in our institute were divided into three groups according to the presence or type of MCs. The Oswestry Disability Index (ODI) and visual analog scale (VAS) were used to assess the outcomes of the treatment.

Results

Based on the achieved results, there was no significant difference between three groups before treatment (P > 0.05). Three months after undergoing nonsurgical treatment, the rates of improved ODI and VAS scores were statistically significantly different (P=0.014, 0.023). After an additional 3 months of treatment, in patients with Modic type I changes, the symptoms significantly improved in comparison with those 3 months prior (P=0.037, 0.026), while that improvement did not occur in patients with Modic type II changes (P > 0.05).

Conclusions

The existence of MCs affects the outcomes of nonsurgical treatment in patients with LBP. However, symptoms can be improved after an additional round of treatment for Modic type I changes, while this is not confirmed for Modic type II changes.

Effective treatment options for musculoskeletal pain in primary care: A systematic overview of current evidence

BACKGROUND & AIMS

Musculoskeletal pain, the most common cause of disability globally, is most frequently managed in primary care. People with musculoskeletal pain in different body regions share similar characteristics, prognosis, and may respond to similar treatments. This overview aims to summarise current best evidence on currently available treatment options for the five most common musculoskeletal pain presentations (back, neck, shoulder, knee and multi-site pain) in primary care.

METHODS

A systematic search was conducted. Initial searches identified clinical guidelines, clinical pathways and systematic reviews. Additional searches found recently published trials and those addressing gaps in the evidence base. Data on study populations, interventions, and outcomes of intervention on pain and function were extracted. Quality of systematic reviews was assessed using AMSTAR, and strength of evidence rated using a modified GRADE approach.

RESULTS

Moderate to strong evidence suggests that exercise therapy and psychosocial interventions are effective for relieving pain and improving function for musculoskeletal pain. NSAIDs and opioids reduce pain in the short-term, but the effect size is modest and the potential for adverse effects need careful consideration. Corticosteroid injections were found to be beneficial for short-term pain relief among patients with knee and shoulder pain. However, current evidence remains equivocal on optimal dose, intensity and frequency, or mode of application for most treatment options.

CONCLUSION

This review presents a comprehensive summary and critical assessment of current evidence for the treatment of pain presentations in primary care. The evidence synthesis of interventions for common musculoskeletal pain presentations shows moderate-strong evidence for exercise therapy and psychosocial interventions, with short-term benefits only from pharmacological treatments. Future research into optimal dose and application of the most promising treatments is needed.

Changes in Sleep With Auricular Point Acupressure for Chronic Low Back Pain

The purpose of this study was to report sleep quality from 4 weeks of auricular point acupressure that was designed for chronic low back pain and determine the relationship between pain intensity and sleep quality. Participants were randomized into the APA group (n = 30) or the sham-APA group (n = 31). At baseline assessment, 87% of the participants reported poor sleep quality. Participants who received APA had decreased daytime disturbance and improved global Pittsburgh Sleep Quality Index scores at end of intervention (EOI) and 1-month follow up compared to participants in the sham-APA group. For the APA group, both the sleep duration and wake after sleep onset decreased gradually during the 4-week APA (0.56% and 0.23% daily change, respectively).

Acute and Chronic Low Back Pain

Low back pain is an extremely common presenting complaint that occurs in upward of 80% of persons. Treatment of an acute episode of back pain includes relative rest, activity modification, nonsteroidal anti-inflammatories, and physical therapy. Patient education is also imperative, as these patients are at risk for further future episodes of back pain. Chronic back pain (>6 months' duration) develops in a small percentage of patients. Clinicians' ability to diagnose the exact pathologic source of these symptoms is severely limited, making a cure unlikely. Treatment of these patients should be supportive, the goal being to improve pain and function.

Day-to-Day Changes of Auricular Point Acupressure to Manage Chronic Low Back Pain: A 29-day Randomized Controlled Study

OBJECTIVE

The purpose of this study was to determine the effects of a 4-week auricular point acupressure (APA) treatment on chronic low back pain (CLBP) outcomes and examine the day-to-day variability of CLBP in individuals receiving APA for CLBP over 29 days.

DESIGN

This was a prospective, randomized controlled trial (RCT). Data were collected at baseline, during each of the four office visits for APA treatment, after the completion of the 4-week intervention, and 1 month after the last treatment. A daily diary was given to each participant to record his or her APA practices, analgesic use, and pain intensity.

INTERVENTIONS

APA was used to manage CLBP. The participants received one APA treatment per week for 4 weeks.

PATIENTS AND SETTING

Sixty-one participants with CLBP were randomized into either a real APA or sham APA treatment group. Participants were recruited from primary care offices and clinics or through the Research Participant Registry at the University of Pittsburgh.

RESULTS

Among participants in the real APA group, a 30% reduction of worst pain was exhibited after the first day of APA treatment, and continuous reduction in pain (44%) was reported by the completion of the 4-week APA. This magnitude of pain reduction reached the clinically significant level of improvement reported in other clinical trials of chronic pain therapies. Analgesic use by participants in the real APA group also was reduced compared with use by participants in the sham group.

CONCLUSION

This study shows that APA is a promising pain management strategy that is not invasive and can be self-managed by participants for CLBP. Given the day-to-day fluctuation in ratings, the tighter ecologic assessment of pain scores and other treatment parameters are an important pragmatic aspect of the design of chronic pain studies.

Auricular point acupressure to manage chronic low back pain in older adults: a randomized controlled pilot study

This prospective, randomized clinical trial (RCT) pilot study was designed to (1) assess the feasibility and tolerability of an easily administered, auricular point acupressure (APA) intervention and (2) provide an initial assessment of effect size as compared to a sham treatment. Thirty-seven subjects were randomized to receive either the real or sham APA treatment. All participants were treated once a week for 4 weeks. Self-report measures were obtained at baseline, weekly during treatment, at end-of-intervention (EOI), and at a 1-month follow-up. A dropout rate of 26% in the real APA group and 50% in the sham group was observed. The reduction in worst pain from baseline to EOI was 41% for the real and 5% for the sham group with a Cohen's effect size of 1.22 (P < 0.00). Disability scores on the Roland Morris Disability Questionnaire (RMDQ) decreased in the real group by 29% and were unchanged in the sham group (+3%) (P < 0.00). Given the high dropout rate, results must be interpreted with caution; nevertheless, our results suggest that APA may provide an inexpensive and effective complementary approach for the management of back pain in older adults, and further study is warranted.

Efficacy of auricular therapy for pain management: a systematic review and meta-analysis

Objective. The objective of this systematic review and meta-analysis was to assess the efficacy of auricular therapy by including a sham therapy control group. Methods. Relevant, randomized clinical trials (RCTs) were identified by searching medical related databases from, depending on journal, 1900 (at the earliest) to 1994 (at the latest) through May 2013. The outcome measure was a pain intensity score. Results. Twenty-two RCTs were identified and 13 RCTs were included for meta-analysis. In these studies, auricular therapy provided significant pain relief when compared to a sham or control group. The overall standardized mean differences (SMD) was 1.59 (95% CI [-2.36, -0.82]) (13 trials, total subject numbers = 806), indicating that, on average, the mean decrease in pain score for auricular therapy group was 1.59 standard deviations greater than the mean decrease for the sham control. In terms of the efficacy of the different treatment methods, auricular acupressure boasts the largest strength of evidence for pain relief, followed by auricular acupuncture. Electroacupuncture stimulation did not show significant evidence for efficacy, which may be due to the small sample size (i.e., only 19 subjects were included). Conclusion. Further large-scale RCTs are needed to determine the efficacy of auricular therapy for pain.

Acute and chronic low back pain

Low back pain is an extremely common presenting complaint that occurs in upward of 80% of persons. Treatment of an acute episode of back pain includes relative rest, activity modification, nonsteroidal anti-inflammatories, and physical therapy. Patient education is also imperative, as these patients are at risk for further future episodes of back pain. Chronic back pain (>6 months' duration) develops in a small percentage of patients. Clinicians' ability to diagnose the exact pathologic source of these symptoms is severely limited, making a cure unlikely. Treatment of these patients should be supportive, the goal being to improve pain and function.

A randomized clinical trial of auricular point acupressure for chronic low back pain: a feasibility study

Objectives. This prospective, randomized clinical trial (RCT) was designed to investigate the feasibility and effects of a 4-week auricular point acupressure (APA) for chronic low back pain (CLBP). Methods. Participants were randomized to either true APA (true acupoints with taped seeds on the designated ear points for CLBP) or sham APA (sham acupoints with taped seeds but on different locations than those designated for CLBP). The duration of treatment was four weeks. Participants were assessed before treatment, weekly during treatment, and 1 month following treatment. Results. Participants in the true APA group who completed the 4-week APA treatment had a 70% reduction in worst pain intensity, a 75% reduction in overall pain intensity, and a 42% improvement in disability due to back pain from baseline assessment. The reductions of worst pain and overall pain intensity in the true APA group were statistically greater than participants in the sham group (P < 0.01) at the completion of a 4-week APA and 1 month followup. Discussion. The preliminary findings of this feasibility study showed a reduction in pain intensity and improvement in physical function suggesting that APA may be a promising treatment for patients with CLBP.

Treatment of chronic low back pain: a randomized clinical trial comparing multidisciplinary group-based rehabilitation program and oral drug treatment with oral drug treatment alone

OBJECTIVE

This randomized clinical trial examined the efficacies of a group-based multidisciplinary rehabilitation program and oral drug treatment versus oral drug treatment alone in Iran.

METHODS

A total of 197 patients with chronic low back pain were randomized to either intervention group (n=97) receiving a group-based, 5-session multidisciplinary rehabilitation program plus oral medication or to control group (n=100) receiving just oral medication. At baseline and at 3 and 6-month follow-ups, patients filled out questionnaires on health-related quality of life (36-item Short-form General Health Survey) and disability Questionnaires (Quebec Disability Scale and Ronald-Morris Disability). Repeated measure analysis of variance was used to compare 2 groups during time.

RESULTS

The 2 groups were comparable regarding all baseline characteristics (P>0.05). There were significant differences within each group by time in terms of all subscales of 36-item Short-form (P<0.01) except for mental health (P=0.7). Furthermore, there were significant differences between groups in terms of all domains of SF-36 scale except for general health (P=0.06), social function (P=0.08) and role emotional (P=0.7). Furthermore, according to the scores of Ronald-Morris Disability Questionnaire and Quebec Disability Scale, the disability of patients in the intervention group was improved over time significantly (P=0.01 and P<0.0001, respectively).

DISCUSSION

The findings revealed that the group-based multidisciplinary program could improve most domains of quality of life in chronic low back pain patients in the 6-month period. However, there were no significant differences between two groups in sub scales such as general health, social function and role emotional.

What is mechanical back pain and how best to treat it?

Back pain is one of the most common patient complaints brought forth to physicians. Mechanical back pain accounts for 97% of cases, arising from spinal structures such as bone, ligaments, discs, joints, nerves, and meninges. Acute back pain in the absence of progressive neurologic deficits and other underlying nonmechanical causes may be treated conservatively, with specific emphasis on maintaining activity levels and function. Mechanical back pain persisting for more than 4 to 6 weeks may warrant further diagnostic testing and imaging. Common causes of mechanical back pain include spinal stenosis, herniated discs, zygapophysial joint pain, discogenic pain, vertebral fractures, sacroiliac joint pain, and myofascial pain. A wide variety of treatments are available, with different treatments specifically targeted toward different causes. A balanced approach, which takes into account patient psychosocial factors and incorporates multidisciplinary care, increases the likelihood of success from back pain interventions.

Cyclobenzaprine ER for muscle spasm associated with low back and neck pain: two randomized, double-blind, placebo-controlled studies of identical design

OBJECTIVE

To evaluate efficacy and tolerability of once-daily cyclobenzaprine extended release (CER) 15- and 30-mg capsules in patients with muscle spasm associated with acute, painful musculoskeletal conditions.

METHODS

Two identically designed, randomized, double-blind, placebo- and active-controlled, parallel-group studies in patients aged 18-75 years with muscle spasm associated with neck or back pain. Patients received CER 15 or 30 mg once daily, cyclobenzaprine immediate release (CIR) 10 mg three times daily, or placebo for 14 days. Primary efficacy measures were patient's rating of medication helpfulness and physician's clinical global assessment of response to therapy at day 4. Secondary measures were patient's rating of medication helpfulness and physician's clinical global assessment of response (days 8 and 14), relief from local pain, global impression of change, restriction in activities of daily living, restriction of movement, daytime drowsiness, quality of nighttime sleep (days 4, 8, and 14), and quality of life (days 8 and 14).

RESULTS

A total of 156/254 randomized patients in study 1 and 174/250 in study 2 completed 14 days of treatment. Significant improvements in patient's rating of medication helpfulness were reported with CER versus placebo (CER 30 mg, study 1, p = 0.007; CER 15 mg, study 2, p = 0.018) at day 4. Significant improvements with CER 30 mg versus placebo were also seen at day 4 in study 1 for patient-rated global impression of change (p = 0.008), relief of local pain (p = 0.004), and restriction of movement (p = 0.002). Neither study reported differences between study groups on the physician's clinical global assessment. Improvements with CER were comparable to that of CIR. In both studies, daytime drowsiness was reported more frequently in active treatment groups than in the placebo group; however, reports of drowsiness decreased over time in all groups. In general, daytime drowsiness was reported more frequently in CIR groups than in CER groups. More adverse events were reported in the active treatment groups versus placebo and were similar in the CER and CIR groups, except somnolence, which occurred more frequently with CIR.

CONCLUSIONS

Once-daily CER 15 mg (study 2) and CER 30 mg (study 1) were effective in treating muscle spasm associated with painful musculoskeletal conditions after 4 days of treatment. Differences between CER and placebo groups did not reach statistical significance on all efficacy measures, and the protocols were not powered to detect differences between active treatment arms. CER was generally safe and well tolerated, with low rates of somnolence.