***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 Fifth Commission on Antiepileptic Drugs of the International League Against Epilepsy was asked to advise the ILAE Executive on the place of new drugs in the treatment of patients with newly diagnosed or chronic epilepsy . With the licensing of a significant number of new antiepileptic drugs ( AEDs ) in the last 5 - 10 years , there is an obvious need for these new treatments to be introduced efficiently and effectively to benefit the care and management of people with epilepsy . Implicit in this will be a determination of the comparative efficacy , tolerability , and overall effectiveness against st and ard ( existing ) AEDs and against other new drugs . Although many of the issues relating to comparative studies were addressed in Guidelines for the Clinical Evaluation of Antiepileptic Drugs , produced by the Fourth Commission , several complex ethical and method ological problems remain that would benefit from further discussion aim ed at the establishment of some form of consensus . Although determination of the relative risks of rare but potentially serious idiosyncratic adverse reactions and teratogenicity can be determined only by adequate postmarketing surveillance , other issues concerning the efficacy , tolerability , and effectiveness of new drugs can best be determined within the context of well- design ed r and omized ( or otherwise controlled ) clinical trials ( RCTs ) . It is the design , structure , and outcomes of such comparative RCTs that dem and further consideration . Many of the difficulties arise because the most meaningful and satisfactory comparative studies will essentially be those that compare monotherapy with a new agent with monotherapy with alternative agents . The Commission recognizes that several different parties have interests in comparative studies . First and foremost patients and their doctors require adequate information to guide daily practice in an “ evidence -based ” way so that patients can make fully informed decisions about their drug treatment . Individual pharmaceutical manufacturers need to know how their drug compares with other products so that a drug can be appropriately positioned in the market . Licensing authorities have traditionally ignored issues of comparative BACKGROUND Magnetic resonance (MR)-based T2 relaxation time measurement is a sensitive technique to detect neuropathological changes such as intramyelinic edema in vivo . OBJECTIVE To determine whether vigabatrin ( VGB ) causes an increase in T2 relaxation time in patients with newly diagnosed localization-related epilepsy over 1 year . METHODS Patients with newly diagnosed localization-related epilepsy who participated in a VGB-carbamazepine ( CBZ ) monotherapy trial were included . All were scanned on a 1.5 T Siemens SP63 Magnetom scanner . T2 maps of the brain were obtained at baseline and at follow-up 1 year later . Nine control subjects had repeated hippocampal T2 maps with a median interval of approximately 2 years . RESULTS 23 patients ( 12 on VGB and 11 on CBZ ) were included . There were no increased T2 relaxation times in the VGB treated group at follow-up and no significant differences between the two antiepileptic drug groups . There was a trend for the temporal and frontal white matter T2 relaxation times to be lower on follow-up in the patients compared to the control subjects . CONCLUSION The findings do not suggest that intramyelinic edema occurs in patients taking monotherapy VGB for 1 year At present , 34 patients aged 15 to 63 years with newly diagnosed epilepsy have been r and omly assigned to vigabatrin ( n = 17 ) or carbamazepine ( n = 17 ) . Evaluation of clinical data , neuropsychological assessment , quantitative spectral electroencephalogram ( EEG ) , and somatosensory- and visual-evoked potentials at baseline and after a 3 months ' maintenance phase are presented for 12 patients on vigabatrin and for 11 patients on carbamazepine .  Among these patients , retention rate in the maintenance phase of the study is 75 % for vigabatrin patients ( two noncompliant patients and one nonresponder dropped out ) followed up for a mean of 11 months ( range , 5 to 16 months ) . The retention rate for carbamazepine is 100 % for the 11 patients , followed up for a mean of 9 months ( range , 3 to 17 months ) . Patients receiving vigabatrin showed significant improvements in sustained concentration and tasks requiring flexible mental processing after the 3-month maintenance period , compared to baseline . In the carbamazepine group , there was improvement only in delayed list recall , and in contrast , errors in visuomotor tasks requiring processing increased significantly . Patients on carbamazepine demonstrated slowed occipital mean frequencies , but vigabatrin treatment was not associated with any significant quantitative EEG changes . Significant prolongation of somatosensory-evoked potential N19 latencies was seen with both carbamazepine and vigabatrin . ( J Child Neurol 1991;6(Suppl):2S60 - 2S69 ) Carbamazepine ( CBZ ) is a drug of choice for the treatment of simple or complex partial seizures and secondary generalized seizures in adults and children .  Vigabatrin ( VGB ) is a relatively new second line antiepileptic drug and was first registered for use in Pol and more than ten years ago . Few reports have been published on the comparison of efficacy of VGB in children with epilepsy . The objective of this study is to evaluate the safety , efficacy and EEG effects of initial VGB monotherapy compared with initial CBZ monotherapy in children with newly diagnosed epilepsy . We present results of a prospect i ve , outpatient and open study carried out in the University Hospital Center in Białystok . Twenty-six children with partial epilepsy treated with VGB and 28 patients treated with CBZ were studied . The evaluation of the efficacy of the two drugs did not reveal any significant differences . Very good ( reduction > 75 % ) seizure control was achieved in 22 out of 26 patients ( 84.6 % ) in the VGB group . One patient had a 50 - 75 % decrease of seizures ( good effect ) , similarly one child had a 25 - 50 % reduction of seizures ( mild effect ) . In two patients , we observed increased seizures ( myoclonic jerks ) . Very good seizure control was achieved in 17 out of 28 patients ( 60.7 % ) in the CBZ group . Good seizure control was achieved in 5 out of 28 patients ( 17.8 % ) and mild control was seen in two children . No improvement was observed in 4 ( 14 % ) of the patients . The EEG background activity was improved in VGB-treated patients . No effect on the EEG background activity was observed in CBZ-treated children . VGB seems to be a safe and effective antiepileptic drug as primary monotherapy for epilepsy in children with similar proportion of side effects as CBZ Reporting of adverse events ( AEs ) in r and omized clinical trials ( RCTs ) is often lacking and with limited application in the real world , as RCTs are of short duration , include small numbers of patients , and are selective for subjects lacking in comorbid conditions . It is not surprising that new and unexpected safety concerns emerge with any new drug after it has been launched and used by many more patients . Part of the problem is inherent to the way safety data are reported in RCTs . This article focuses on some of the shortcomings of AE reporting in RCTs , especially those involving tumor necrosis factor ( TNF ) inhibitors . Discussion focuses on reporting of " time-to-event " issues , use of st and ardized incidence ratios for comparison to normal population or disease controls , use of " patient-years " when reporting AEs , and the problem of adequate sample size and power calculations that are lacking in safety outcome data trials OBJECTIVE To evaluate the efficacy , safety , and cognitive effects of initial vigabatrin monotherapy compared with initial carbamazepine monotherapy in patients with newly diagnosed epilepsy . DESIGN Open , r and omized , controlled design . Follow-up period of 12 months . SETTING University hospital with an epilepsy center . PATIENTS A total of 100 patients , aged 15 to 64 years , classified as suffering from partial seizures and /or generalized tonic-clonic seizures were r and omized to either vigabatrin or carbamazepine monotherapy . Fifty-nine patients with a single epileptic seizure and no antiepileptic drug treatment served as a control population for objective safety measures . OUTCOME MEASURES To evaluate the comparative efficacy and toxicity of vigabatrin and carbamazepine , the drug success rate ( ie , the proportion of patients continuing successful treatment with the r and omly assigned drug ) after 12 months of steady-state treatment was used . To evaluate the safety of the drugs in addition to reported side effects , visual evoked potential recordings and neuropsychological evaluation were performed during follow-up . RESULTS During the 12-month follow-up period , 60 % of patients receiving vigabatrin and carbamazepine were treated successfully . Vigabatrin caused fewer side effects that required discontinuation of therapy . However , vigabatrin had to be discontinuated more often owing to lack of efficacy , and fewer of the successfully treated patients receiving vigabatrin achieved total freedom from seizures . Vigabatrin had no detrimental effects on cognitive functions . Retrieval from both episodic and semantic memory and flexibility of mental processing improved significantly in patients successfully treated with vigabatrin . CONCLUSION Vigabatrin seems to be an effective and safe antiepileptic drug as primary monotherapy for epilepsy with fewer cognitive side effects than carbamazepine PURPOSE The risk factors for  visual field loss attributable to vigabatrin ( VAVFL ) are equivocal . This multinational , prospect i ve , observational study aim ed to clarify the principal/major factors for VAVFL . METHODS Interim analysis of three groups with refractory partial epilepsy , stratified by age ( 8 - 12 years ; > 12 years ) and exposure to vigabatrin ( VGB ) .  Group I comprised participants treated with VGB for > or=6 months , Group II participants previously treated with VGB for > or=6 months who had discontinued the drug for > or=6 months  and Group III those never treated with VGB .  Perimetry was undertaken at least every six months , for up to 36 months ; results were evaluated masked to drug exposure . RESULTS Based upon 563 participants in the locked data set , 432 yielded one or more Conclusive visual field examinations .  For Group I , the frequency of VAVFL at the last Conclusive examination was 10/32 ( 31.2 % ) for those aged 8 - 12 years and 52/125 ( 41.6 % ) for those aged > 12 years . For Group II , the proportions were 4/39 ( 10.3 % ) and 31/129 ( 24.0 % ) . No cases resembling VAVFL manifested in Group III . VAVFL was associated with duration of VGB therapy ( Odds ratio [ OR ] 14.2 ; 95 % CI 5.0 to 40.5 ) ; mean dose of VGB  ( OR 8.5 ; 95 % CI 2.2 to 33.2 ) ; and male gender ( OR 2.1 ; 95 % CI 1.2 to 3.7 ) . VAVFL was more common with static than kinetic perimetry ( OR 2.3 , 95 % CI 1.3 to 4.2 ) . CONCLUSIONS The therapeutic benefit of VGB is counteracted by the progressive accrual of the risk of VAVFL with continued exposure and with increase in mean dose Vigabatrin is effective as add‐on therapy in about 50 % of patients with partial epilepsy refractory to drugs . Furthermore , at least half of the original responders maintain the response over several years . As monotherapy , both vigabatrin and carbamazepine seem to be successful in a similar proportion of newly diagnosed patients with epilepsy , but carbamazepine monotherapy fails more often due to side‐effects and vigabatrin more often due to lack of efficacy .  However , vigabatrin monotherapy seems to be extremely well tolerated , particularly in relation to cognitive function The clinical efficacy and safety of vigabatrin ( VGB ) as add-on therapy for pharmaco-resistant focal epilepsies is well established . However , for an objective evaluation , the effects of the drug in the monotherapy of newly diagnosed subjects should be determined . With this aim , VGB was compared , in a r and omized , response conditional cross-over study , with carbamazepine ( CBZ ) , the most widely prescribed drug in focal epilepsies . Fifty-one patients with complex partial ( CP ) seizures were r and omly assigned to either the VGB or the CBZ group and evaluated after an initial 4 month period . The cross-over to the alternative drug was carried out , for an analogous period , only in cases with persisting seizures or in the presence of intolerable side effects . Patients who did not respond to either drug were subsequently treated with a combination of VGB and CBZ . No significant difference was revealed in the efficacies of  VGB and  CBZ ; a complete control of seizures was obtained in 17/37 patients ( 45.9 % ) treated with VGB and in 20/39 patients ( 51.3 % ) treated with CBZ . The side effects were somewhat more frequent ( 41 % ) and severe with CBZ than with VGB ( 21.6 % ) . The power to detect a 20 % difference between the two drugs was 75 % . The combination of the two drugs suppressed the seizures in 5 out of 14 resistant cases . The preliminary results in this small number of patients are encouraging and suggest that VGB may be considered as a first-line drug for epilepsy with CP seizures and as a valid alternative when other monotherapies are ineffective or poorly tolerated O 
    Output:
    
No significant differences favoured VGB or CBZ in terms of time to treatment withdrawal and time to achieve six-month remission after dose stabilisation from r and omisation , but results did show a disadvantage for VGB on time to first seizure after r and omisation .
Compared with CBZ , VGB was associated with more occurrences of weight gain and fewer occurrences of skin rash and drowsiness .
No differences in visual field defects and visual disturbances were noted .
Data are currently insufficient to address the risk-benefit balance of VGB versus CBZ monotherapy for epilepsy .