***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Traditional and largely qualitative review s of evidence are now giving way to much more structured systematic overviews that use a quantitative method to calculate the overall effect of treatment . The latter approach is dependent on the quality of primary studies , which may introduce bias if they are of poor method ologic quality . OBJECTIVE To test the hypothesis that the inclusion of poor- quality trials in meta-analyses would bias the conclusions and produce incorrect estimates of treatment effect . METHODS An overview of r and omized trials of antiestrogen therapy in subfertile men with oligospermia was performed to test the hypothesis . Data sources included online search ing of MEDLINE and Science Citation Index data bases between 1966 and 1994 , scanning the bibliography of known primary studies and review articles , and contacting experts in the field . After independent , blind assessment , nine of 149 originally identified studies met the inclusion criteria and were selected . We assessed study quality independently . Outcome data from each study were pooled and statistically summarized . RESULTS There was a marginal improvement in pregnancy rate with antiestrogen treatment ( odds ratio , 1.6 ; 95 % confidence interval , 0.9 to 2.6 ) . Sensitivity analyses on the basis of method ologic quality demonstrated that poor- quality studies produced a positive effect with treatment , whereas no benefit was observed with high- quality studies . CONCLUSION The results of a meta- analysis are influenced by the quality of the primary studies included . Method ologically , poor studies tend to exaggerate the overall estimate of treatment effect and may lead to incorrect inferences OBJECTIVE To test the hypotheses that both amitriptyline and gabapentin are more effective in relieving neuropathic pain  than an active placebo , diphenhydramine . DESIGN R and omized , controlled , double blind , triple crossover 8-week trial . SETTING Veterans Affairs medical center . PARTICIPANTS Community dwelling adults with spinal cord injury ( N=38 ) were recruited by telephone , letters , and flyers . INTERVENTION Eight-week trial each of amitriptyline , gabapentin , and diphenhydramine . MAIN OUTCOME MEASURES Pain intensity measured with a 10-cm visual analog scale ( VAS ) and an 11-point ( 0 - 10 ) numeric rating scale ( NRS ) and depressive symptomatology measured with the Center for Epidemiologic Studies Depression Scale-Short Form ( CESD-SF ) . RESULTS Baseline VAS scores for participants with low ( < 10 ) CESD-SF scores was 4.61 and for those with high scores ( > or = 10 ) it was 7.41 . At week 8 , in participants with high baseline CESD-SF scores , amitriptyline ( mean , 4.21 ) was more effective than diphenhydramine ( mean , 6.67 ; P=.035 ) , and there was a nonsignificant trend suggesting that amitriptyline may be more effective than gabapentin ( mean , 6.68 ; P=.061 ) . Gabapentin was no more effective than  diphenhydramine  ( P=.97 ) . There was no significant difference among the medications for those with lower CESD-SF scores . Results could not be attributed to dropout rates , order or dose of medications , amount of medication taken for breakthrough pain , or side effects . CONCLUSIONS Amitriptyline is more efficacious in relieving neuropathic pain than diphenhydramine at or below the level of spinal cord injury in people who have considerable depressive symptomatology Twenty-four adults with phantom limb pain ( PLP ) and /or residual limb pain ( RLP ) participated in a double-blind crossover trial . Participants were r and omly assigned to receive gabapentin or placebo and later crossed over to the other treatment , with a 5-week washout interval in which they did not receive medication . Gabapentin was titrated from 300 mg to the maximum dose of 3,600 mg . Measures of pain intensity , pain interference , depression , life satisfaction , and functioning were collected throughout the study . Analyses revealed no significant group differences in pre- to posttreatment change scores on any of the outcome measures . More than half of the participants reported a meaningful decrease in pain during the gabapentin phase compared with about one-fifth who reported a meaningful decrease in pain during the placebo phase . In this trial , gabapentin did not substantially affect pain . More research on the efficacy of gabapentin to treat chronic PLP and RLP is needed ABSTRACT Although acute pain in patients with herpes zoster can be severe and has a substantial impact on health‐related quality of life , there have been no r and omized clinical trials of oral medications specifically for its ongoing treatment . A r and omized clinical trial was conducted in which 87 subjects ⩾50 years of age with herpes zoster within 6 calendar days of rash onset and with worst pain in the past 24 h ⩾ 3 on a 0–10 rating scale initiated 7 days of treatment with famciclovir in combination with 28 days of treatment with either controlled‐release ( CR ) oxycodone , gabapentin , or placebo . Subjects were evaluated for adverse effects of treatment , acute pain , and health‐related quality of life . The results showed that CR‐oxycodone and gabapentin were generally safe and were associated with adverse events that reflect well‐known effects of these medications . Discontinuing participation in the trial , primarily associated with constipation , occurred more frequently in subjects r and omized to CR‐oxycodone ( 27.6 % ) compared with placebo ( 6.9 % ) . Treatment with CR‐oxycodone reduced the mean worst pain over days 1–8 ( p = 0.01 ) and days 1–14 ( p = 0.02 ) relative to placebo but not throughout the entire 28‐day treatment period as pain resolved in most subjects . Gabapentin did not provide significantly greater pain relief  than placebo , although the data for the first week were consistent with a modest benefit . By demonstrating that CR‐oxycodone is safe , generally adequately tolerated , and appears to have efficacy for relieving acute pain , the results of this clinical trial provide a foundation for evidence ‐based treatment for acute pain in herpes zoster Abstract Background : Neuropathic pain is a common complaint after traumatic spinal cord injury ( SCI ) .  Gabapentin , a synthetic structural analogue of GABA , has been shown to have beneficial effects in the treatment of neuropathic pain in other diagnostic groups ; however , no st and ardized clinical trial has been performed to evaluate its efficacy after SCI . Design : A 1 0-week , prospect i ve , r and omized , double-blind , crossover , and placebo-controlled clinical trial . Objective : To determine the efficacy of gabapentin in the treatment of SCI-related neuropathic pain . Methods : Seven subjects with neuropathic pain , who were more than 30 days post-SCI , completed the study . Two groups received a 4-week course of gabapentin and placebo in a r and omized crossover design with a 2-week washout period . The Neuropathic Pain Scale was used to record daily pain levels . Data were analyzed using the Wilcoxon signed rank test . Results : Gabapentin has some beneficial effects on certain types of neuropathic pain . There was a significant decrease of " unpleasant feeling " and a trend toward a decrease in both the " pain intensity " and " burning sensation " at the fourth week of gabapentin treatment compared with those on the placebo . No significant difference was found among other pain descriptors during the gabapentin and placebo treatment , although this may have been limited by the small sample size and low maximum dosage of gabapentin . Conclusions : Gabapentin reduces certain types of neuropathic pain in the SCI population . Future studies with larger sample sizes , higher dosages , and quicker titration will help further determine the efficacy of gabapentin in the treatment of SCI-related neuropathic pain BACKGROUND Reports of gabapentin use in diabetic peripheral neuropathy pain stimulate a need for controlled trials to determine its comparative efficacy to the therapeutic st and ard of amitriptyline hydrochloride . OBJECTIVE To determine the efficacy of gabapentin compared with amitriptyline in treating diabetic peripheral neuropathy pain . DESIGN Prospect i ve , r and omized , double-blind , double-dummy , crossover study . SETTING Veterans Affairs San Diego Healthcare System , Ambulatory Care Clinic . PATIENTS Twenty-eight veterans were referred by their primary care providers . Two patients withdrew before r and omization because of no neuropathic pain after washout ; a third withdrew for unexpected surgery that required analgesics . Three patients withdrew because of adverse effects and 1 for protocol violation . INTERVENTIONS Patients with stable glycemic control and neuropathic pain r and omized to 6 weeks of therapy with gabapentin , 900 to 1800 mg/d , or amitriptyline hydrochloride , 25 to 75 mg/d , with a 1-week washout before crossover . MAIN OUTCOME MEASURES Pain relief measured by pain scale with verbal descriptors and global pain score assessment at treatment end . RESULTS Participants and investigators were blinded throughout . Mean dosages were of gabapentin , 1565 mg/d , and of amitriptyline hydrochloride , 59 mg/d . Sixty-five percent of patients reached maximum dose with gabapentin and 54 % with amitriptyline .  Mean score diary analysis showed pain relief with gabapentin and amitriptyline was not significantly different ( P = .26 ) . Global data were obtained from 21 of 25 enrolled patients who completed the study . Moderate or greater pain relief was experienced in 11 ( 52 % ) of 21 patients with gabapentin and 14 ( 67 % ) of 21 patients with amitriptyline . There were no significant period or carry-over effects ( P = .35 ) . CONCLUSIONS Although both drugs provide pain relief , mean pain score and global pain score data indicate no significant difference between gabapentin and amitriptyline . Gabapentin may be an alternative for treating diabetic peripheral neuropathy pain , yet does not appear to offer considerable advantage over amitriptyline and is more expensive . Larger trials are necessary to define gabapentin 's place in treating diabetic peripheral neuropathy pain Abstract Chronic masticatory myalgia ( CMM ) can be defined as constant pain in the masticatory muscles for more than 6 months and is influenced by the central nervous system . The antiepileptic agent gabapentin acts central ly and is used for managing different types of chronic pain conditions . The objective of this study was to evaluate the analgesic action of gabapentin on CMM . In this 12‐week r and omized controlled clinical trial 50 patients were r and omly allocated into two study groups : 25 received gabapentin and 25 received placebo . The outcome measures utilized were pain reported on a VAS ( VAS‐pain ) , Palpation Index ( PI ) and impact of CMM on daily functioning reported on a VAS ( VAS‐function ) . Thirty‐six patients completed the study .  Gabapentin showed to be clinical ly and statistically superior to placebo in reducing pain reported by patients  ( gabapentin = 51.04 % ; placebo = 24.30 % ; P = 0.037 ) , masticatory muscle hyperalgesia  ( gabapentin = 67.03 % ; placebo = 14.37 % ; P = 0.001 ) and impact of CMM on daily functioning  ( gabapentin = 57.70 % ; placebo = 16.92 % ; P = 0.022 ) . It can be concluded from this study that gabapentin is effective for the management of CMM Objective To replicate and extend previous research concerning the validity and utility of using pain quality measures in clinical trials . Methods One hundred fifty-eight patients with moderate-to-severe postherpetic neuralgia were r and omly assigned to 1 of 3 treatment conditions : ( 1 ) extended release gabapentin ( G-ER ) 1800 mg once-daily administered in the evening ; ( 2 ) G-ER 1800 mg asymmetric divided dose ( 600 mg AM and 1200 mg PM ) ; or ( 3 ) placebo G-ER . A measure of different pain qualities , the Neuropathic Pain Scale , was administered as a secondary measure in this study before , during , and after the treatment . Results The results suggest that G-ER , especially when administered twice-daily , have the greatest effects on sharp , dull , sensitive , and itchy pain . Few between-condition effects were found for the global ratings of intensity or unpleasantness , and for hot , cold , deep , or surface pain qualities . Conclusions The results provide further support for the importance of assessing specific pain qualities as outcomes in clinical trials . The findings may also be used by clinicians for identifying those patients for whom G-ER may be particularly effective ; that is , patients with postherpetic neuralgia presenting with  pain  described as sharp , dull , sensitive , or itchy Abstract Background : Postherpetic neuralgia ( PHN ) is a neuropathic pain syndrome that may develop subsequent to healing of herpes zoster rash . Objectives : This study aim ed to determine the efficacy and safety of gabapentin extended-release ( gabapentin ER ) tablets for the treatment of patients with PHN and to determine whether optimal benefits might be achieved with once-daily ( QD ) or divided-dose ( DD ) administration . Methods : This was a 10-week , r and omized , double-blind , placebo-controlled , multicentre trial comparing gabapentin ER ( total daily dose 1800 mg ) either QD or as an asymmetrical DD with placebo in 407 patients with post-zoster pain for ≥3 months 
    Output:
    
There was no obvious difference between st and ard gabapentin formulations and recently-introduced extended-release or gastro-retentive formulations , or between different doses of gabapentin .
Adverse events occurred significantly more often with gabapentin .
Second tier evidence , with potentially important residual biases , showed that gabapentin at doses of 1200 mg or more was effective for some people with some painful neuropathic pain conditions .
The outcome of at least 50 % pain intensity reduction is regarded as a useful outcome of treatment by patients , and the achievement of this degree of pain relief is associated with important beneficial effects on sleep interference , fatigue , and depression , as well as quality of life , function , and work .
The levels of efficacy found for gabapentin are consistent with those found for other drug therapies in postherpetic neuralgia and painful diabetic neuropathy