***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: The purpose of the present investigation was to compare the analgesic efficacy of flurbiprofen , a nonsteroidal anti-inflammatory drug , which is a phenyl propionic acid derivative , with acetaminophen and placebo in 63 adult out patients with moderate to severe dental pain following periodontal surgery . After surgery was completed under local anesthesia , the patients received under double-blind conditions an envelope containing four tablets of either flurbiprofen 100 mg , acetaminophen 500 mg , or placebo and they were instructed to take one tablet every 6 hours when postoperative pain reached moderate to severe intensity . To determine analgesic efficacy and patients recorded pain intensity on a scale of 0 to 3 . Patients were allowed to remedicate after 1 hour if pain was not reduced . Flurbiprofen was shown to possess an adequate analgesic effect superior to either placebo ( P less than 0.005 ) or acetaminophen ( P less than 0.01 ) in the parameters studied . Our results seem to further support earlier data obtained with the drug in dental patients with postoperative pain after the surgical removal of impacted third molars ; therefore , it is concluded that flurbiprofen used as directed is a new alternative for the proper treatment of pain following periodontal surgery BACKGROUND The purpose of this r and omized double-blind study was to compare the efficacy and safety of propacetamol 2 g ( an i.v . acetaminophen 1 g formulation ) administered as a 2-min bolus injection ( n=50 ) or a 15-min infusion ( n=50 ) with oral acetaminophen 1 g ( n=50 ) or placebo ( n=25 ) for analgesia after third molar surgery in patients with moderate to severe pain after impacted third molar removal . METHODS All patients were evaluated for efficacy during the initial 6 h period after treatment administration ( T(0 ) ) and for safety during the entire week after T(0 ) . RESULTS The onset of analgesia after propacetamol was shorter ( 3 min for bolus administration , 5 min for 15-min infusion ) than after oral acetaminophen ( 11 min ) . Active treatments were significantly better for all parameters ( pain relief , pain intensity , patient 's global evaluation , duration of analgesia ) than placebo ( P<0.05 ) . Adverse events were more frequent after propacetamol , especially pain at the injection site . Propacetamol bolus result ed in a much higher incidence of local adverse events than the infusion ( propacetamol bolus 90 % vs propacetamol infusion 52 % ) with no clinical ly significant benefits in terms of analgesic efficacy . CONCLUSION I.V. propacetamol , administered as a 15-min infusion , is a fast-acting analgesic agent . It is more effective in terms of onset of analgesia than a similar dose of oral acetaminophen Abstract  Variability  in patients ' response to interventions in pain and other clinical setting s is large . Many explanations such as trial methods , environment or culture have been proposed , but this paper sets out to show that the main cause of the variability may be r and om chance , and that if trials are small their estimate of magnitude of effect may be incorrect , simply because of the r and om play of chance . This is highly relevant to the questions of ‘ How large do trials have to be for statistical accuracy ? ’ and ‘ How large do trials have to be for their results to be clinical ly valid ? ’ The true underlying control event rate ( CER ) and experimental event rate ( EER ) were determined from single‐dose acute pain analgesic trials in over 5000 patients . Trial group size required to obtain statistically significant and clinical ly relevant ( 0.95 probability of number‐needed‐to‐treat within ±0.5 of its true value ) results were computed using these values . Ten thous and trials using these CER and EER values were simulated using varying group sizes to investigate the variation due to r and om chance alone . Most common analgesics have EERs in the range 0.4–0.6 and CER of about 0.19 . With such efficacy , to have a 90 % chance of obtaining a statistically significant result in the correct direction requires group sizes in the range 30–60 . For clinical relevance nearly 500 patients are required in each group . Only with an extremely effective drug ( EER>0.8 ) will we be reasonably sure of obtaining a clinical ly relevant NNT with commonly used group sizes of around 40 patients per treatment arm . The simulated trials showed substantial variation in CER and EER , with the probability of obtaining the correct values improving as group size increased . We contend that much of the variability in control and experimental event rates is due to r and om chance alone . Single small trials are unlikely to be correct . If we want to be sure of getting correct ( clinical ly relevant ) results in clinical trials we must study more patients . Credible estimates of clinical efficacy are only likely to come from large trials or from pooling multiple trials of conventional ( small ) size In a double‐blind , r and omized , single‐dose trial the analgesic contribution of acetaminophen , 1000 mg , and codeine , 60 mg , was determined . The study was a 2 × 2 factorial experiment in which 120 patients suffering from pain as a result of oral surgery rated their pain intensity and pain relief for up to 5 hours after a single dose of one of : 1000 mg acetaminophen , 60 mg codeine , 1000 mg acetaminophen plus 60 mg codeine , or placebo . The factorial analysis showed that both 1000 mg acetaminophen and 60 mg codeine made a statistically significant ( P < 0.05 ) contribution to the analgesic effectiveness of the combination on all measures of efficacy ( sum of pain intensity differences , largest pain intensity difference , total pain relief , largest pain relief , and time to remedication ) . The incidence of adverse effects did not appear to differ among the treatments , including placebo To determine the relative analgesic efficacy of ibuprofen 400 mg and acetaminophen 1000 mg , we conducted a single-dose , double-blind , placebo-controlled , r and omized clinical trial using a st and ard assay for analgesic agents , the dental pain model . At regular intervals over 6 hours , 184 patients who had undergone dental impaction surgery rated pain intensity and relief on categorical scales and pain half-gone on a dichotomous nominal scale ; a categorical overall evaluation was completed at the end of 6 hours . Both active agents were effective compared to placebo . Ibuprofen 400 mg was more effective than acetaminophen 1000 mg for Sum Pain Intensity Difference ( SPID ) , Total Pain Relief ( TOTPAR ) , sum pain half-gone , and overall evaluation ( P less than .05 to P less than .001 ) . The time-effect curves demonstrated a greater peak effect and longer duration of action for ibuprofen 400 mg compared to acetaminophen 1000 mg . Side effects were reported in five ibuprofen patients , 11 acetaminophen-treated patients , and seven placebo patients . Based on the results of this clinical study , we conclude that ibuprofen 400 mg is a safe and more effective analgesic than acetaminophen 1000 mg for patients with acute pain A double-blind , placebo-controlled trial was carried out in 299 patients suffering from post-episiotomy pain to compare the analgesic effectiveness and tolerance of single doses of 500 mg dipyrone and 500 mg paracetamol . Assessment s of pain relief over a 6-hour period showed that dipyrone produced significantly better results than placebo within half an hour of intake and maintained this superiority throughout the 6 hours . It also afforded consistently better pain relief than paracetamol and was significantly more effective at the 6-hour assessment . Side-effects were few and mild Lysine clonixinate ( LC ) , an effective and well tolerated non-morphinic analgesic whose mechanism of action is basically due to the inhibition of cyclo-oxygenase , was assessed with a double-blind r and omized dummy design versus paracetamol ( P ) on 200 patients suffering from pain after minor dental surgery . Patients received according to their needs 1 or 2 tablets of 125 mg lysine clonixinate or 500 mg paracetamol every 8 h during 48 h or until pain relief . Both groups , each composed of 100 patients , were comparable in terms of demographic conditions ( t test ) , initial symptoms ( chi-square test ) , characteristics of the extracted dental pieces , surgical complications and wound treatment ( chi-square test ) . Pain intensity scores and daily average intake of tablets ( 3.4/day ) documented in the patients ' diary revealed no statistically significant differences between the two treatments ( chi-square test ) . It was found that spontaneous pain measured using a visual analogue scale ( VAS ) decreased significantly in both treatment groups at the 24-h control examination . The following values were observed in the LC group : baseline 4.38 + /- 1.7 ; 24-h * 1.20 + /- 1.4 ; 48-h * 0.36 + /- 1.2 . In the P group the values were : baseline 4.28 + /- 1.6 ; 24-h * 1.11 + /- 1.4 ; 48-h * 0.30 + /- 0.7 ( * p < 0.05 ) . Other variables like facial swelling and night pain , evaluated on a score from 0 to 4 and symptom presence or absence respectively , showed a similar response . ( ABSTRACT TRUNCATED AT 250 WORDS Background : A r and omized , double‐blind , placebo‐controlled single oral dose study was done in order to examine whether codeine has an additive analgesic effect to that of paracetamol for moderate and strong postoperative pain after abdominal surgery . The maximum recommended single dose of paracetamol 1000 mg ( Paracet ® ) was compared with a combination of a submnximal dose of paracetamol 800 mg plus codeine 60 mg ( Paralgin forte ® ) and placebo for pain relief  after Caesarean section in 125 patients 1 Dipyrone 1.0 g , paracetamol 1.0 g and placebo were compared in a double-blind parallel group study in patients with episiotomy pain . 2 Patients were stratified according to severity of initial pain ( severe or moderate ) and the three treatments were r and omized for each of these two groups . 3 Two-hundred and sixty-four patients entered the study : five patients were excluded from analysis ; 127 patients had ' severe ' pain , 132 ' moderate ' pain . 4 Both drugs were more effective than placebo , and dipyrone was significantly more effective than paracetamol , particularly where initial pain was severe . 5 The efficacy of dipyrone 1.0 g was compared with paracetamol 1.0 g in relieving pain after tooth extraction . 6 Ninety patients entered the study and 87 were analyzed without stratification according to initial pain severity . 7 Dipyrone was consistently and significantly more effective than paracetamol at every assessment & NA ; There is uncertainty over whether the patient group in which acute pain studies are conducted ( pain model ) has any influence on the estimate of analgesic efficacy . Data from four recently up date d systematic review s of aspirin 600/650 mg , paracetamol 600/650 mg , paracetamol 1000 mg and ibuprofen 400 mg were used to investigate the influence of pain model . Area under the pain relief versus time curve equivalent to at least 50 % maximum pain relief over 6 h was used as the outcome measure . Event rates with treatment and placebo , and relative benefit ( RB ) and number needed to treat ( NNT ) were used as outputs from the meta‐analyses . The event rate with  placebo was systematic ally statistically lower for dental than postsurgical pain for all four treatments . Event rates with analgesics , RB and NNT were infrequently different between the pain models . Systematic difference in the estimate of analgesic efficacy between dental and postsurgical pain models remains unproven , and , on balance , no major difference is likely The efficacy of diclofenac sodium ( Voltarol ) with and without paracetamol in the control of post-surgical dental Summary Acetylsalicylic acid(ASA ) was compared with paracetamol(P ) in a double-blind crossover study , in which essentially the same operation was performed on two separate occasions in 32 healthy patients , who required surgical removal of bilateral “ identically ” impacted wisdom teeth . Sixteen patients were given the drugsboth before and after(b & a-group ) the operations ( 0.5 g on the pre-operative evening , followed by 0.5 g × 4 for 3 days ) ; the other 16 patients did not start treatment until 2 hoursafter(a-group ) the operations . A number of objective and subjective factors were assessed , including swelling , bleeding , pain and preference , and were used to make comparisons of the pre- , per- and post-operative courses . About 50 % greater post-operative swelling was associated withASA compared toP , either if medication was begun prior to surgery or if the drugs were given only after operation . In theb & a-group , interference with platelet function and prolonged pre-operative bleeding time were produced byASA ( 8.9 vs 6.5 min ) , but the per-operative blood loss was not significantly increased ( 7.8 vs 7.4 ml ) . In both groupsASA tended to increase post-operative bleeding and the formation of ha 
    Output:
    
Reported adverse events were mainly mild and transient , and occurred at similar rates with 1000 mg paracetamol and placebo .
A single dose of paracetamol provides effective analgesia for about half of patients with acute postoperative pain , for a period of about four hours , and is associated with few , mainly mild , adverse events