***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: Nonsteroidal antiinflammatory drugs have been used to obtain preemptive analgesia . We investigated , in this r and omized , double-blind study , whether sublingual ( s.l . ) piroxicam given before was more effective than that given after surgery . Fifty-two patients scheduled for laparoscopic bilateral inguinal hernia repair under general anesthesia were enrolled . Group PRE ( 25 patients ) received 40 mg of piroxicam s.l . 2 h before surgery and a placebo 10 min after surgery . Group POST ( 27 patients ) were treated with a placebo 2 h before surgery and received 40 mg of piroxicam s.l . 10 min after surgery . After an initial dose of 100 mg tramadol IV , patient-controlled analgesia with tramadol was started and recorded . Visual analog scores were assessed in the recovery and at 6 , 20 , and 30 h postoperatively . Significantly lower visual analog scores were found in group PRE at 6 and 20 h. Significantly smaller cumulative tramadol consumption was observed after 30 h in group PRE . In summary , our findings suggest that preoperative s.l . piroxicam is more effective than the postoperative administration . Because of the low pain scores in both groups , the clinical relevance of these findings is not clear from this study The purpose of this prospect i ve clinical trial was to investigate the analgesic efficacy of three oral medication groups on postoperative endodontic pain in male and female dental patients , with an emphasis on analgesic differences between the sexes . Forty-three patients were administered ibuprofen 600 mg , placebo , or pentazocine 50 mg/0.5 mg naloxone in a r and omized , double-blinded manner . Beginning immediately after endodontic treatment , patients took the assigned medication every 6 hours for 24 hours and recorded their degree of discomfort on a 100-mm visual analog scale . Statistical analysis of the data showed that ibuprofen 600 mg provided statistically significantly greater analgesia than placebo at 6 and 12 hours ( P = 0.0014 and 0.0024 ) , and pentazocine/naloxone provided statistically significantly greater analgesia than placebo at 12 hours ( P = 0.0084 ) . Sex-dependent differences were noted within the pentazocine/naloxone group , which showed significantly greater analgesia in females compared with males ( P = 0.007 ) Successful management of endodontic pain represents a continuing challenge . The purpose of this r and omized , double-blind , placebo-controlled , parallel-group trial was to compare the pain reducing effect of oral preparations of meloxicam , piroxicam , and placebo in endodontic emergency patients . A total of 51 patients who presented to the Tehran University endodontic clinic and one private dental clinic were invited to participate . Patients were asked to evaluate their pretreatment pain with a visual-analog scale . After root canal therapy they were r and omly assigned to one of three groups : meloxicam , piroxicam , or placebo . Each patient was sent home with a visual-analog scale to fill out at 8 and 24 h after completion of therapy . The results of this study showed no significant differences between efficacy of meloxicam , piroxicam , and placebo , but a significant effect of the time factor in reducing postoperative pain in all treatment groups was observed STUDY OBJECTIVE To determine whether intravenous injection of lornoxicam 30 minutes before skin incision provides better pain relief after varicocelectomy than postoperative administration of lornoxicam . DESIGN Prospect i ve , double-blind , r and omized clinical investigation . SETTING Operating room and postoperative recovery area . PATIENTS 44 ASA physical status I and II adult male patients undergoing varicocelectomy . INTERVENTIONS Patients were r and omized either to receive 8 mg lornoxicam infusion 30 minutes before skin incision , followed by saline infusion immediately after skin closure ( group 1 ) , or to receive the identical injections but in reverse order ( group 2 ) . All patients received local anesthesia with bupivacaine . MEASUREMENTS Postoperative pain scores were evaluated hourly for the first 8 hours after surgery , then at 12 , 16 , 20 , and 24 hours after surgery , using a 10-cm visual analog scale . Time to first analgesic request and patients ' global assessment s also were recorded . MAIN RESULTS Patients in group 1 reported significantly lower pain scores ( P < 0.05 ) at all time intervals except at 24 hours and better global assessment ( P = 0.001 ) than did group 2 . There were significantly fewer patients in the preemptive group than group 2 who required rescue analgesic within the first 24 hours ( 0 % vs 22.7 % ; P = 0.024 ) . Mean time to first analgesic request was also significantly longer in the preemptive group ( P = 0.001 ) . CONCLUSION Intravenous lornoxicam administered before surgery has a better analgesic effect for varicocelectomy than when administered postoperatively Background : Postendodontic pain ( PEP ) has always been a major problem for patients and dentists and NSAIDs are being used to relieve PEP and it is supposed that some benzodiazepines may potentiate facilitate the analgesic effects of the NSAIDs . This study was conducted to evaluate the effect of alprazolam on the analgesic effect of ibuprofen in PEP treatment . Methods : This r and omized double-blind clinical trial was conducted on 45 patients aged 20 - 45 years who were subjected of root canal treatment . A written informed consent was obtained from each patient . The subjects were r and omly divided into three groups ; placebo , ibuprofen ( 400 mg ) and alprazolam ( 0.5 ) mg + ibuprofen ( 400 mg ) . The intensity of pain was recorded using visual analog scale ( VAS ) at 4 , 6 , 12 , 24 , 48 and 72 hours after drug administration . Results : Of the participants , twenty six ( 57.8 % ) were males and 19 patients ( 42.2 % ) were females . Four hours after starting treatment , the VAS scores in the placebo and ibuprofen -treated groups were significantly higher than ibuprofen and alprazolam+ibuprofen groups ( 4.93±1.16 , 3.67±1.88 and 2.67±1.11 , respectively , p<0.0001 ) . The VAS scores  in alprazolam + ibuprofen group ( 2.33±1.05 ) were significantly lower at 6 hours after treatment when compared to the other groups ( Ibuprofen : 3.00±1.36 and placebo : 3.08±1.74 , P=0.002 ) . This decrease in VAS score sustained to 12 hours after the start of alprazolam + ibuprofen treatment when compared to ibuprofen or placebo receiving group alone ( p<0.003 ) . The average pain score in female patients who received alprazolam + ibuprofen was significantly lower than males at 12 hours ( 1.3±0.6 v.s 2.14±0.9 , P=0.002 ) and 24 hours after treatment ( 0.88±0.6 v.s 1.86±0.9 , P=0.003 ) . Conclusion : According to the results , it can conclude that alprazolam may enhance the analgesic efficacy  of ibuprofen in postendodontic pain To determine if prophylactic etodolac would significantly reduce postendodontic pain , when compared with ibuprofen or placebo , 36 patients consented to single blind oral administration of either 400 mg of etodolac , 600 mg of ibuprofen , or a placebo  , before conventional one-appointment root canal therapy .  Patient-reported visual analog scale ratings of pain intensity were conducted upon initial clinical presentation , immediately postoperative , 4 , 8 , 12 , 24 , 48 , and 72 h after initiation of root canal therapy . Results showed that prophylactic ibuprofen administration significantly reduced postendodontic pain at 4 and 8 h after initiation of root canal therapy , when compared with etodolac and a placebo .  Patients with a periapical diagnosis of acute apical periodontitis or with a Phoenix abscess showed a significant increased need for additional medication after completion of root canal therapy , compared with all other periapical diagnoses Background Periapical lesions are inflammatory diseases that result in periapical bone destruction because of host defensive – microbial disturbances . Objective To evaluate the role of prophylactic ibuprofen and N-acetylcysteine ( NAC ) on the levels of tumor necrosis factor alpha ( TNF- α ) , interleukin- 6(IL-6 ) and IL-17 and post-treatment pain level in chronic periapical lesions . Material s and methods Eighty patients with chronic apical lesions less than 1 cm were r and omly assigned to receive NAC tablets ( 400 mg ) , ibuprofen tablets ( 400 mg ) , NAC ( 400 mg)/ibuprofen ( 200 mg ) combination and placebo 90 minutes prior to sampling . Periapical exu date s were collected from root canals . TNF- α , IL-6 and IL-17 levels were determined by ELISA and post-treatment pain was assessed using a visual analog scale ( VAS ) . Results There was a significant difference in IL-6 level  between ibuprofen group and placebo ( p = 0.019 ) . Significant difference in IL-17 level was observed between NAC/ibuprofen combination group and placebo ( p = 0.043 ) . Four hours after treatment , a significant difference was observed in VAS pain score  between ibuprofen group and placebo ( p = 0.017 ) . Eight hours post-treatment , VAS pain score for NAC group was statistically lower than placebo group ( p = 0.033 ) . After 12 hours VAS pain score showed a significant decrease in NAC group compared to placebo ( p = 0.049 ) . Conclusion The prophylactic ibuprofen and NAC failed to clearly reflect their effect on cytokines levels in exu date s of chronic periapical lesions . On the other h and it seems that NAC can be a substitute for ibuprofen in the management of post endodontic pain Achieving successful anesthesia and pain control in a predictable , efficient manner is a challenge in the endodontic treatment of vital inflamed lower molars . The aim of this study was to evaluate the effect of oral ketamine on the dosage of local anesthetics required and postoperative pain management for irreversibly inflamed m and ibular molars . In this r and omized double-blind placebo-controlled clinical trial , 36 patients with irreversibly inflamed m and ibular molars were r and omly divided into two groups of 18 . Ten mg of ketamine dissolved in 20 ml of fruit juice was administered orally to patients in the experimental group . The control group was given 20 ml of fruit juice alone as a placebo . After 30 min , inferior alveolar nerve block ( IANB ) anesthesia was induced using one cartridge of 2 % lidocaine and 1:100000 epinephrine . Teeth were tested after 5 to 10 min using an electrical pulp tester . In patients showing a positive response , another IANB injection was applied , and the total number of anesthetic cartridges used was recorded . Postoperative pain was evaluated using a visual analogue scale ( VAS ) . In addition , use of analgesic in the first 24 h after treatment was monitored using a question naire . Data were analyzed by t test using SPSS software . There were no significant differences in age  or gender between the two groups . The number of anesthetic cartridges used in the ketamine group was significantly less than that in the control group ( P = 0.003 ) . Furthermore , postoperative pain in the ketamine group was significantly lower ( P = 0.019 ) . Also the number of analgesic tablets taken in the ketamine group was significantly lower ( P = 0.011 ) . It can be concluded that a low dose of ketamine might be beneficial for enhancing the effect of local anesthetics STUDY OBJECTIVE To determine the optimum time of administration of diclofenac in patients undergoing ambulatory knee arthroscopy : either preoperatively or postoperatively . DESIGN R and omized , double-blind study . SETTING Ambulatory surgical unit in a tertiary referral hospital . PATIENTS 127 ASA physical status I and II patients undergoing ambulatory knee arthroscopy . INTERVENTIONS Patients were r and omized into three groups . The Preop group received 50 mg of potassium diclofenac orally 1 hour preoperatively and a placebo 30 minutes postoperatively . The Pre+postop group received 25 mg of potassium diclofenac 1 hour preoperatively and 25 mg diclofenac 30 minutes postoperatively . The Postop group received a placebo 1 hour before surgery and 50 mg of potassium diclofenac 30 minutes postoperatively . MEASUREMENTS AND MAIN RESULTS The Postop group received a placebo 1 hour preoperatively and 50 mg of potassium diclofenac 30 min postoperatively . Postoperatively , patients used intravenous patient-controlled analgesia ( PCA ) with fentanyl 
    Output:
    
Our meta-regression analysis provided the evidence for association between some study covariates with treatment effect , each at different follow-ups .
We concluded that the clinicians can manage post-operative endodontic pain by administration of NSAIDs and /or paracetamol .