***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: Objective To examine the prevalence of outcome reporting bias — the selection for publication of a subset of the original recorded outcome variables on the basis of the results — and its impact on Cochrane review s. Design A nine point classification system for missing outcome data in r and omised trials was developed and applied to the trials assessed in a large , unselected cohort of Cochrane systematic review s. Research ers who conducted the trials were contacted and the reason sought for the non-reporting of data . A sensitivity analysis was undertaken to assess the impact of outcome reporting bias on review s that included a single meta- analysis of the review primary outcome . Results More than half ( 157/283 ( 55 % ) ) the review s did not include full data for the review primary outcome of interest from all eligible trials . The median amount of review outcome data missing for any reason was 10 % , whereas 50 % or more of the potential data were missing in 70 ( 25 % ) review s. It was clear from the publications for 155 ( 6 % ) of the 2486 assessable trials that the research ers had measured and analysed the review primary outcome but did not report or only partially reported the results . For reports that did not mention the review primary outcome , our classification regarding the presence of outcome reporting bias was shown to have a sensitivity of 88 % ( 95 % CI 65 % to 100 % ) and specificity of 80 % ( 95 % CI 69 % to 90 % ) on the basis of responses from 62 trialists . A third of Cochrane review s ( 96/283 ( 34 % ) ) contained at least one trial with high suspicion of outcome reporting bias for the review primary outcome . In a sensitivity analysis undertaken for 81 review s with a single meta- analysis of the primary outcome of interest , the treatment effect estimate was reduced by 20 % or more in 19 ( 23 % ) . Of the 42 meta-analyses with a statistically significant result only , eight ( 19 % ) became non-significant after adjustment for outcome reporting bias and 11 ( 26 % ) would have overestimated the treatment effect by 20 % or more . Conclusions Outcome reporting bias is an under-recognised problem that affects the conclusions in a substantial proportion of Cochrane review s. Individuals conducting systematic review s need to address explicitly the issue of missing outcome data for their review to be considered a reliable source of evidence . Extra care is required during data extraction , review ers should identify when a trial reports that an outcome was measured but no results were reported or events observed , and contact with trialists should be encouraged BACKGROUND The use of phenobarbital for childhood epilepsy is controversial because of reported behavioural side-effects ; however , whether this research can validly be extrapolated to developing countries is not clear . We undertook a r and omised comparison of phenobarbital and phenytoin to assess the acceptability and efficacy of phenobarbital as monotherapy for childhood epilepsy in rural India . METHODS Between August , 1995 , and February , 1996 , 109 unselected children aged 2 - 18 years with partial and generalised tonic-clonic epilepsy were identified by population screening . 15 families declined to take part . 94 children were r and omly allocated treatment with phenobarbital ( 1.5 mg/kg daily for 2 weeks ; maintenance dose 3.0 mg/kg daily ; n = 47 ) or phenytoin ( 2.5 mg/kg daily then 5.0 mg/kg daily ; n = 47 ) . Children were followed up for 12 months . The primary outcome measure was the frequency of behavioural side-effects ; behaviour was assessed by the Conners parent rating scale for children aged 6 years and older , and by the preschool behaviour screening question naire ( BSQ ) for those aged 2 - 5 years , at 12 months or at withdrawal from treatment . Analysis was by intention to treat . FINDINGS The mean log-transformed scores on the behaviour rating scales did not differ significantly between the phenobarbital and phenytoin groups ( Conners 2.64 [ SD 0.71 ] vs 2.65 [ 0.89 ] , p = 0.97 ; n = 32 in each group : BSQ 2.12 [ 1.31 ] vs 2.18 [ 1.02 ] , p = 0.94 ; n = 4 vs 3 ) . The odds ratio for behavioural problems  ( phenobarbital vs phenytoin ) was 0.51 ( 95 % CI 0.16 - 1.59 ) . There was no excess in parental reports of side-effects for phenobarbital . We found no difference in efficacy between the study drugs ( adjusted hazard ratio for time to first seizure from r and omisation 0.97 [ 0.28 - 3.30 ] ) . INTERPRETATION This evidence supports the acceptability of phenobarbital as a first-line drug for childhood epilepsy in rural setting s in developing countries PRIMIDONE ( Mysoline ) has been shown to be an effective anticonvulsant drug . 1 - 6 It has been stated that primidone is exceptionally valuable in the control of focal seizures and the " drug of choice " for the treatment of psychomotor seizures . 7 - 9 Previous clinical comparative studies have not contradicted this cl aim . 4,5 One study found that phenobarbital and primidone were equally effective as anticonvulsants with 50 mg of phenobarbital being equivalent to 250 mg of primidone . Another similar study 5 revealed that primidone and phenobarbital are about equally effective as anticonvulsants but more effective than  diphenylhydantoin ( Dilantin ) .  However , as the authors of that study point out , the five day medication trial was not sufficient for maximal anticonvulsant effect of diphenylhydantoin  to occur . Their data revealed a sharp increase in effectiveness of diphenylhydantoin  on the fifth treatment day , while primidone and phenobarbital were relatively more effective on the first and second days . Recent studies have shown that most newly diagnosed epileptic patients can be satisfactorily treated with a single antiepileptic drug . We therefore undertook a prospect i ve r and omised pragmatic trial of the comparative efficacy and toxicity of four major antiepileptic drugs , utilised as monotherapy in newly diagnosed epileptic patients . Between 1981 and 1987 243 adult patients aged 16 years or over , newly referred to two district general hospitals with a minimum of two previously untreated tonic-clonic or partial with or without secondary generalised seizures were r and omly allocated to treatment with phenobarbitone , phenytoin , carbamazepine , or sodium valproate . The protocol was design ed to conform with st and ard clinical practice . Efficacy was assessed by time to first seizure after the start of treatment and time to enter one year remission . The overall outcome with all of the four drugs was good with 27 % remaining seizure free and 75 % entering one year of remission by three years of follow up . No significant differences between the four drugs were found for either measure of efficacy at one , two , or three years of follow up . The overall incidence of unacceptable side effects , necessitating withdrawal of the r and omised drug , was 10 % . For the individual drugs phenobarbitone ( 22 % ) was more likely to be withdrawn than phenytoin ( 3 % ) , carbamazepine ( 11 % ) , and sodium valproate ( 5 % ) . In patients with newly diagnosed tonic-clonic or partial with or without secondary generalised seizures , the choice of drug will be more influenced by considerations of toxicity and costs OBJECTIVE To compare the efficacy and side effects of phenobarbitone ( PB ) , phenytoin ( PHT ) and sodium valproate ( SVP ) in controlling  generalized tonic-clonic convulsions ( GTC ) . DESIGN R and omized , double blind clinical trial . SETTING Out- Patients in a tertiary care hospital . PATIENTS 151 children with GTC , aged 4 - 12 yrs , from Madras city were enrolled . At the end of 2 yrs , 127 children remained in the study . INTERVENTION Each child was given one active drug and 2 placebo tablets .  Clinical , hematological and biochemical evaluations were done every month . Serum drug levels were assessed periodically . MAIN OUTCOME MEASURES Recurrence of convulsion and side effects . RESULTS The proportion of children with recurrence did not differ among the 3 groups . More than one side effect was observed in 16 ( 32 % ) children on PB , 20 ( 40 % ) children on PHT and 9 ( 19 % ) children on SVP and this difference was statistically significant ( p < 0.05 ) . Hyperactivity was the major side effect of PB , observed in 22 % of children . CONCLUSION All 3 drugs were equally effective in controlling seizures . Side effects were minimal with SVP followed by PB . Though side effects were more frequent with PHT , most of them disappeared on adjusting drug dosage . Least expensive phenobarbitone may be preferred as the first drug of choice but , only for pre-school children . SVP is advised for school going children We investigated the neuropsychological effects of carbamazepine , phenobarbital , and phenytoin in 15 partial complex epilepsy patients treated with each drug for 3 months , using a r and omized double-blind , triple crossover design . Neuropsychological evaluation at the end of each treatment period included Digit Span , Selective Reminding Test , Digit Symbol , Finger Tapping , Grooved Pegboard , Choice Reaction Time , P3 evoked potential , and Profile of Mood States . Employing anticonvulsant blood levels and seizure frequencies as covariates , the only significant difference was for Digit Symbol . Performance with phenobarbital was significantly worse than with the other 2 anticonvulsants despite phenobarbital 's having had the lowest overall blood levels . Our data show that patients receiving carbamazepine , phenobarbital , and phenytoin  have comparable neuropsychological performance on most measures . The results suggest that the differential cognitive effects of anticonvulsants may be subtle We conducted a 10-center , double-blind trial to compare the efficacy and toxicity of four antiepileptic drugs in the treatment of partial and secondarily generalized tonic-clonic seizures in 622 adults . Patients were r and omly assigned to treatment with carbamazepine , phenobarbital , phenytoin , or primidone and were followed for two years or until the drug failed to control seizures or caused unacceptable side effects . Overall treatment success was highest with carbamazepine or phenytoin , intermediate with phenobarbital , and lowest with primidone ( P less than 0.002 ) . Differences in failure rates of the drugs were explained primarily by the fact that primidone caused more intolerable acute toxic effects , such as nausea , vomiting , dizziness , and sedation . Decreased libido and impotence were more common in patients given primidone . Phenytoin caused more dysmorphic effects and hypersensitivity . Control of tonic-clonic seizures did not differ significantly with the various drugs . Carbamazepine provided complete control of partial seizures more often than primidone or phenobarbital ( P less than 0.03 ) . Overall , carbamazepine and phenytoin are recommended drugs of first choice for single-drug therapy of adults with partial or generalized tonic-clonic seizures or with both The efficacy , bioavailability , and tolerance of carbamazepine in epilepsy were evaluated in a prospect i ve , double-blind study . The study was made in 45 institutionalized patients whose seizures were not controlled completely by combinations of currently available an-tiepileptic drugs in adequate dosages as determined by serum concentrations . In this population , carbamazepine was equal in efficacy to phenobarbital or diphenylhydantoin in controlling seizure frequency , and side effects were minimal . Serum concentrations of carbamazepine  were measured up to 13.7 rncg per milliliter , with 70 percent of the values ranging from 5 to 10 mcg per milliliter . Individual episodes of transient leukopenia occurred during the 21-day lest period , but a statistically significant incidence of leukopenia was not observed The efficacy and bioavailability , and tolerance to  carbamazepine when administered with phenobarbital or phenytoin or with both drugs were evaluated in a prospect i ve , double‐blind study of patients whose seizures were not completely controlled by currently available antiepileptic drugs in usually therapeutic dosages as determined by serum levels . During each of four 21‐day treatment periods , one fourth of the patients received daily doses of : ( 1 ) carbamazepine ( 1,200 mg ) and phenytoin ( 300 mg ) ; ( 2 ) carbamazepine ( 1,200 mg ) and phenobarbital ( 300 mg ) ; ( 3 ) phenytoin ( 300 mg ) and phenobarbital ( 300 mg ) ; or ( 4 ) carbamazepine ( 1,200 mg ) , with phenytoin ( 300 mg ) and phenobarbital ( 300 mg ) . The treatment periods were separated by 2 wk of each patient 's usual pre study medication . Treatment with all three drugs was the most efficacious for seizure control . Serum carbamazepine concentration was significantly decreased when the drug was administered with either phenytoin or phenobarbital or both BACKGROUND The medical treatment of childhood epilepsy is largely influenced by clinical trials in adult patients . We know of only one r and omised comparative 
    Output:
    
These results indicate a statistically significant clinical advantage for phenytoin in terms of treatment withdrawal .
The results of this review show that phenobarbitone was significantly more likely to be withdrawn than phenytoin .
Given that no significant differences for seizure outcomes were found , the higher withdrawal rate with phenobarbitone may be due to adverse effects .