***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: A double-blind , 18-center , balanced trial of diflunisal vs. cyclobenzaprine HCl vs. these two drugs combined vs. placebo produced complete results from 175 patients . They had sought treatment at the cooperating centers for acute painful spasms of the back within a day or two of trauma or strain . Global results over the 7 to 10 days of observations revealed a clinical ly and statistically significant superiority of the combined therapy by Day 4 ( P=0.006 ) and almost all patients recovered within a week to 10 days . A combination therapy with an effective safe analgesic and a true muscle relaxant for less than a week appears to be an excellent relief measure for acute back problems The reduction of pain by two antidepressants , clomipramine and mianserin , was , in this study on 253 patients with chronic idiopathic pain syndrome , found to be not better than a placebo when all patients were compared independently of the classification of pain . The improvement rate was around 40 % after 6 weeks of treatment when using a 50 % or better reduction in pain level . However , in patients who fulfilled a checklist definition of minor to major depression ( 30 % of the total patient material ) clomipramine was superior to mianserin and placebo with an improvement rate of 75 % after 6 weeks . Using pain curves over time as outcome measure in the various clinical pain categories it was found that both mianserin and clomipramine seemed superior to placebo in patients with tension headache , but in patients with low back pain syndrome placebo was superior to the two antidepressants . No difference among the three treatments was found in patients with burning mouth syndrome or in patients with abdominal pain . These differences underline the importance of study ing specific pain syndromes rather than composite groups of patients with idiopathic pain . The clinical significance of these pain curves needs further placebo controlled investigations & NA ; To assess the efficacy of nortriptyline , a tricyclic antidepressant , as an analgesic in chronic back pain without depression , we conducted a r and omized , double‐blind , placebo‐controlled , 8‐week trial in 78 men recruited from primary care and general orthopedic setting s , who had chronic low back pain ( pain at T‐6 or below on a daily basis for 6 months or longer ) . Of these 57 completed the trial ; of the 21 who did not complete , four were withdrawn because of adverse effects . The intervention consisted of inert placebo or nortriptyline titrated to within the therapeutic range for treating major depression ( 50–150 ng/ml ) . The main outcome endpoints were pain ( Descriptor Differential Scale ) , disability ( Sickness Impact Profile ) , health‐related quality of life ( Quality of Well‐Being Scale ) , mood ( Beck Depression Inventory , Spielberger State Anxiety Inventory , Hamilton Anxiety/Depression Rating Scales ) , and physician rated outcome ( Clinical Global Impression ) . Reduction in pain intensity scores was significantly greater for participants r and omized to nortriptyline ( difference in mean change 1.68 , 95 % −0.001 , CI −3.36 , P=0.050 ) , with a reduction of pain by 22 % compared to 9 % on placebo . Reduction in disability marginally favored nortriptyline ( P=0.055 ) , but health‐related quality of life , mood , and physician ratings of overall outcome did not differ significantly between treatments . Subgroup analyses of study completers supported the intent‐to‐treat analysis . Also , completers with radicular pain on nortriptyline ( n=5 ) had significantly ( P<0.05 ) better analgesia and overall outcome than did those on placebo ( n=6 ) . The results suggest noradrenergic mechanisms are relevant to analgesia in back pain . This modest reduction in pain intensity suggests that physicians should carefully weigh the risks and benefits of nortriptyline in chronic back pain without depression Thirty-seven patients with chronic back pain were entered into a r and omised , 3-way , double-blind , cross-over comparison of naproxen sodium 550 mg twice daily , diflunisal 500 mg twice daily , and placebo . Each treatment was given for 14 days after a preadmission wash-out week during which only paracetamol was allowed . Patients were assessed on admission and at the end of each treatment with respect to global pain , night pain , pain on movement , and pain on st and ing .  Both visual analogue scales and simple descriptive scales were used to measure pain . Side effects were elicited by a nonleading question . Both methods of pain measurement gave similar results and were highly correlated . Naproxen sodium was superior to placebo in relieving global pain and depending on the method of measurement , in relieving night pain and pain on movement . Diflunisal showed no significant differences from placebo .  Side effects were similar on all 3 treatments . The final preference of the patients was significantly in favour of the active treatments This report describes a double-blind between-group comparison of Tofranil and placebo in fifty-nine patients admitted to the Joint Service Medical Rehabilitation Unit suffering from low back pain . Patients were given 25 mg of either Tofranil or placebo three times a day for four weeks . Fifteen patients were not included in the analysis , nine dropping out for non-trial related reasons , two dropping out complaining of lost libido and four not taking the tablets , or taking additional drugs . One of the patients complaining of lost libido was taking Tofranil and the other was taking placebo . Over the whole sample there was no significant benefit for Tofranil over placebo as regards physical measurements . Both Tofranil and placebo groups showed a significant improvement during the trial on straight leg raise and backward flexion . For lateral flexion the Tofranil group was significantly worse than the placebo group on entering the trial , and during the trial the Tofranil group improved to match the placebo group . The clinician 's pain and stiffness assessment s and the patients ' pain and stiffness assessment s show a significant improvement for both the Tofranil and placebo groups during the trial . However , no difference is shown between Tofranil and placebo . The psychological tests show no difference between Tofranil and placebo and only a marinal improvenmet over initial condition . Further analysis according to initial diagnosis showed nothing conclusive . Numerically , the use of Tofranil produced a marked improvement in pain and stiffness in patients with ' disc lesion only ' diagnoses , whereas placebo did not produce an improvement . However , this observation was far from reaching statistical significance . Side-effects were not severe for either drug . Additional medication was rarely used The effectiveness of cyclobenzaprine hydrochloride , a new tricyclic skeletal muscle relaxant , was shown in patients with long-term intractable pain of cervical and lumbar origin aggravated by skeletal muscle spasm and tenderness . The investigation was double-blind and r and omized , comparing cyclobenzaprine hydrochloride ( 10 mg three times a day ) with diazepam ( 5 mg three times a day ) and with placebo . After two weeks of treatment , the 16 patients in the cyclobenzaprine group showed an overall improvement in pain variables as did the 16 patients in the diazepam group . No serious adverse reactions to cyclobenzaprine were observed in the study . However , dry mouth due to cyclobenzaprine 's  anticholinergic action and mild degrees of drowsiness were encountered more often than with diazepam or placebo Thirty-nine patients with acute low back pain were treated with amitriptyline ( 150 mg/d ) or acetaminophen ( 2,000 mg/d ) in a controlled double-blind design for 5 weeks . Both groups revealed mild depression , normal coping , and increased anxiety at the beginning , with significant improvement in anxiety state and pain at the end of treatment . A repeated measures analysis of variance demonstrated that amitriptyline was more effective than acetaminophen in reducing pain intensity from the second week of treatment . Age and depression were the only significant pretreatment predictors of posttreatment pain . The study evaluates the significance of these findings Health status measures are being used with increasing frequency in clinical research . Up to now the emphasis has been on the reliability and validity of these measures . Less attention has been given to the sensitivity of these measures for detecting clinical change . As health status measures are applied more frequently in the clinical setting , we need a useful way to estimate and communicate whether particular changes in health status are clinical ly relevant . This report considers effect sizes as a useful way to interpret changes in health status . Effect sizes are defined as the mean change found in a variable divided by the st and ard deviation of that variable . Effect sizes are used to translate “ the before and after changes ” in a “ one group ” situation into a st and ard unit of measurement that will provide a clearer underst and ing of health status results . The utility of effect sizes is demonstrated from four different perspectives using three health status data sets derived from arthritis population s administered the Arthritis Impact Measurement Scales ( AIMS ) . The first perspective shows how general and instrument-specific benchmarks can be developed and how they can be used to translate the meaning of clinical change . The second perspective shows how effect sizes can be used to compare traditional clinical measures with health status measures in a st and ard clinical drug trial . The third application demonstrates the use of effect sizes when comparing two drugs tested in separate drug trials and shows how they can facilitate this type of comparison . Finally , our health status results show how effect sizes can supplement st and ard statistical testing to give a more complete and clinical ly relevant picture of health status change . We conclude that effect sizes are an important tool that will facilitate the use and interpretation of health status measures in clinical research in arthritis and other chronic diseases Twenty-seven investigators participated in a double-blind , parallel placebo-controlled trial of piroxicam involving 278 patients with acute low back pain . Therapy commenced within 48 hours of the injury and continued for 7 days . The drug was given in the recommended regimen of 40 mg once daily for the first 2 days and 20 mg once daily thereafter . After 3 days of therapy , piroxicam patients showed a statistically greater amount of pain relief in the lying ( P<0.001 ) , sitting ( P<0.01 ) , and st and ing ( P<0.01 ) positions , but after 7 days the difference between treatments was no longer significant . After 1 week 's therapy , however , the requirement for additional analgesic was significantly lower in the piroxicam group ( P<0.05 ) , and more piroxicam than placebo patients ( 42 versus 28 ) had returned to work ( P<0.05 ) . Toleration was excellent in most patients , with only 13 % of the piroxicam and 17 % of the placebo group reporting adverse effects of mainly mild or moderate severity . The profile of the adverse effects was similar for both treatments . Piroxicam can provide effective relief of acute low-back pain with good toleration ; it should be considered for use in the initial treatment of this condition A new drug , Cyclobenzaprine hydrochloride ( Flexeril ) , was compared with diazepam ( Valium ) and placebo in double-blind trials for efficacy in treating spasms and pain in the neck and low back . Complex recording methods involving clinical evaluations ( grade d ) , patient self-ratings , goniometry , motion analysis by computer , electromyography of controlled motions and detailed statistical analysis were used . Clinical improvement over two weeks was statistically significant in all treatment groups with a statistically significant preference for Cyclobenzaprine hydrochloride . The most striking improvements recorded were in the electromyographic findings , which showed statistically significant changes for the Cyclobenzaprine  group . Clinical muscle spasms are not accompanied by increased myoelectric activity ; the reverse is true . With improvement , myoelectric activity in back muscles is augmented during prescribed stressful movements as measured by electromyography and computer analysis combined with complex electrogoniometry Chronic low back pain is a common problem that has been noted in several studies to exist as a component of masked depression . To determine the usefulness of imipramine in the treatment of chronic low back pain , either by a direct action or indirectly via resolution of a depressive equivalent , 50 consecutive patients were entered into a controlled trail that employed serum imipramine and desipramine levels and Beck depression question naires . Forty-one patients completed the study , and 48 were used in the statistical analysis .  Imipramine had a statistically significant effect over placebo in most , but not all , of the clinical parameters that were measured . A linear relationship between serum drug levels and reported symptoms was not noted . Only 10 of the 50 patients entered into the study were judged clinical ly depressed and , of these , 7 were depressed according to st and ard criteria . There was no statistically significant difference noted in either the initial or the change in Beck depression scores between those on imipramine and those on placebo . However , among those on the active drug , the patients with a greater symptomatic response had a simultaneous change in the total Beck depression scores ( toward less depression ) that approached statistical significance when compared with those with a less symptomatic response . Although the results are not conclusive , imipramine may possibly be useful in the treatment of chronic low back pain , especially so when it exists as a component of masked depression Two groups of 20 patients each , with mild to moderate acute low back pain with associated muscle spasm of ten days ' duration or less , were treated with a combination of cyclobenzaprine and naproxen or naproxen alone in a r and omized , 14-day open-label trial . Cyclobenzaprine was added to the naproxen regimen as an adjunct to rest and physical therapy for relief of muscle spasm associated with acute , painful , musculoskeletal conditions . The clinical characteristics of each study group , including the number of worker 's compensation patients , were comparable . Combination therapy was associated with less objective muscle spasm and tenderness and greater motion of the lumbosacral spine ( P less than 0.05 ) . There were tr 
    Output:
    
Treatment efficacy for these 5 outcomes was greatest early , in the first few days of treatment , declining after the first week .
Patients receiving cyclobenzaprine  also experienced more adverse effects , the most common being drowsiness .
CONCLUSIONS Cyclobenzaprine is more effective than placebo in the management of back pain ; the effect is modest and comes at the price of greater adverse effects .
The effect is greatest in the first 4 days of treatment , suggesting that shorter courses may be better .