***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 The st and ard method used to determine the potency of antihistaminesis to assess the degree of suppression of skin response to histamine challenge . OBJECTIVES The aims of this study were to compare the efficacy of 3 antihistaminesusing a histamine challenge test and the usefulness of on-site evaluation with that of photographic evaluation of skin-test reactions . METHODS In this prospect i ve , double-blind , crossover study , healthy volunteerswere given cetirizine 5 mg ( CTZ-5 ) and 10 mg ( CTZ-10 ) , loratadine 10 mg ( LOR ) , fexofenadine 60 mg BID ( FEX ) , and placebo ( PLC ) , in a r and omly assigned order , with an interval of at least 1 week between treatments . Before and 0.5 to 24 hours after administration , the areas of flare and wheal induced by histamine iontophoresis were measured directly ( on site ) by 1 evaluator and by another evaluator using photographic images on a computer monitor . RESULTS Ten healthy volunteers ( 6 men , 4 women ; mean age , 28.2 years[range , 20 - 39 years ] ; mean weight , 60.7 kg [ range , 41 - 81 kg ] ) were enrolled . The data from 9 subjects were analyzed ; the data from 1 subject were omitted because the subject used an over-the-counter cold medication containing diphenhydramine several times during the study . By both methods , all antihistamines were shown to suppress flare significantly from 4 to 24 hours after administration . CTZ was most potent in suppressing both flare and wheal . For flare , the areas as measured using on-site evaluation were larger overall than those measured using photographic evaluation , but the shapes of the time-course graphs were similar for both . Overall , the flare area measurements started to decrease significantly from baseline values 4 hours after drug administration , reached a nadir at 10.5 hours , and remained significantly lower compared with baseline values at 24 hours . Comparisons between antihistamines showed significant differences in mean flare areas between the 2 doses of CTZ and LOR from 8 to 12 hours after administration in both evaluation methods . The wheal areas were significantly reduced from baseline values by most of the antihistamines 4 to 12 hours after drug administration , reached their lowest values at 10.5 hours , and returned to near-baseline values at 24 hours . Comparisons with PLC values at each time point , however , showed significant differences only for CTZ-5 and CTZ-10 from 4 to 12 hours after administration . Comparison between antihistamines showed significant differences in mean flare areas between the 2 doses of CTZ and LOR from 8 to 12 hours after administration in both evaluation methods . Although the flare areas measured by both methods correlated linearly ( r = 0.90 ; P < 0.001 ) , the correlation for wheal areas was weaker ( r = 0.76 ; P < 0.001 ) . CONCLUSIONS In this study in healthy volunteers , single doses of CTZ 5 mg and CTZ 10 mg were more potent compared with single-dose LOR 10 mg and FEX 60 mg BID in suppressing skin response . Although linear correlations were found between skin-response areas , as measured by on-site and photographic evaluation , it was difficult to differentiate between wheal and flare by photographic evaluation , especially when a typical wheal was suppressed to slightly edematous erythema by antihistamines AIMS To compare the onset and duration of action of the new antihistamine levocetirizine with that of the second-generation antihistamine fexofenadine using the Vienna Challenge Chamber ( VCC ) . The latter is an environment where subjects can be exposed to specific aeroallergens in controlled and reproducible conditions allowing for precise comparisons of anti-allergic drugs . METHODS Ninety-four subjects received a single dose of levocetirizine 5 mg , fexofenadine 120 mg or placebo in a r and om order using a three-way cross-over design . On day 1 , subjects were exposed to grass pollens ( 1500 grains/m(3 ) ) in the VCC over a period of 4 h. Treatment was given 2 h after the start of challenge . On day 2 , 22 h after drug intake , subjects were again exposed to pollens for 6 h. Specified symptoms were assessed by the subjects every 15 min using 5-point scales . The main efficacy parameter was the change from baseline in the Major Symptom Complex Score ( MSCS = sum of rhinorrhea , sneezing , itchy nose and eyes ) . RESULTS Baseline characteristics , including symptoms scores , were similar in the three study groups . During the first 2 h after drug intake both antihistamines achieved clinical ly relevant and significant ( P < 0.001 ) improvements in symptom scores . Twenty-two to 24 h after drug intake , mean ( SEM ) MSCS reductions were : 1.9 ( 0.3 ) after placebo ( baseline of 9.7 ) , 3.8 ( 0.3 ) after fexofenadine ( baseline of 9.9 ) , and 5.1 ( 0.3 ) after levocetirizine ( baseline of 9.8 ) . Levocetirizine was significantly ( P < 0.001 ) more effective than fexofenadine with a score difference of 1.3 ( 95 % CI 0.7 , 1.9 ) . This was maintained until the end of the study ( up to 28 h ) . CONCLUSIONS A rapid onset of action in alleviating seasonal allergic rhinitis ( SAR ) symptoms of subjects exposed to grass pollens in the VCC was observed after levocetirizine and fexofenadine . Levocetirizine was more effective than fexofenadine at and later than 22 h after drug intake , an indication of the longer- duration of action of levocetirizine AIMS To assess whether fexofenadine in a range of doses from 80 to 180 mg has any disruptive effects on aspects of psychomotor and cognitive function in comparison with placebo , loratadine and promethazine , an antihistamine known to produce psychomotor and cognitive impairment . METHODS Twenty-four healthy volunteers received fexofenadine 80 mg , 120 mg and 180 mg , loratadine 10 mg , promethazine 30 mg ( as a positive internal control ) and placebo in a six-way crossover , double-blind study . Following each dose , subjects were required to perform a series of tests of cognitive function and psychomotor performance at 1.5 , 3 , 6 , 9 , 12 and 24 h post dose . The test battery included critical flicker fusion ( CFF ) , choice reaction time ( CRT ) and  assessment of subjective sedation ( LARS ) . Overall levels of activity were monitored by means of wrist mounted actigraphs throughout each of the 24 h experimental periods . RESULTS Fexofenadine at all doses tested was not statistically different from placebo in any of the tests used and loratadine did not cause any significant impairment of cognitive function . Significant impairments were found following promethazine . Promethazine caused a significant reduction in CFF threshold and this effect was evident up to 12 h post dose ( P<0.05 ) . There was a significant increase in recognition reaction time at 3 and 6 h post promethazine administration , and the drug caused a significant ( P<0 . 002 ) increase in the percentage of ' sleep-like ' activity from actigraph records during the daytime . CONCLUSIONS Fexofenadine at doses up to 180 mg appears free from disruptive effects on aspects of psychomotor and cognitive function in a study where the psychometric assessment s have been shown to be sensitive to impairment , as evidence d by the effects of the verum control promethazine 30 mg This is the first U.S.-based study to compare efficacy and safety of desloratadine with fexofenadine in subjects with symptomatic seasonal allergic rhinitis ( SAR ) . In this double-blind study , subjects were r and omized to desloratadine , 5 mg ( n = 290),fexofenadine , 180 mg ( n = 288 ) , or placebo ( n = 144 ) once daily for 15 days . Primary end point was mean change from baseline to study end in morning instantaneous total symptom score ( AM NOW TSS ) excluding congestion . Secondary measures included change from baseline in the morning/evening reflective TSS ( AM/PM PRIOR TSS ) excluding congestion , AM NOW individual symptom score ( AM NOW ISS ) including congestion , and the AM/PM PRIOR ISS including congestion . Subjects self-evaluated their symptoms on a five-point scale . Mean AM NOW TSSs were significantly reduced from baseline at day 15 with desloratadine ( p = 0.006 ) and fexofenadine ( p = 0.024 ) versus placebo . Desloratadine and fexofenadine were not statistically different ( p = 0.491 ) ; the upper limit of the 95 % CI for desloratadine to fexofenadine ( 0.259 ) was within the prespecified noninferiority margin of 0.7 U. Decrease in mean AM/PM PRIOR TSS excluding congestion was comparable between desloratadine and fexofenadine ( p = 0.405 ; CI = 0.221 ) but was significantly greater with both active treatments versus placebo ( desloratadine , p < 0.001;fexofenadine , p = 0.003 ) . Desloratadine and fexofenadine provided greater reduction in the AM NOW ISS and AM/PM PRIOR ISS ( both including congestion ) versus placebo ; reductions were comparable between active treatments . All treatments were well tolerated .  Desloratadine , 5 mg , and fexofenadine , 180 mg , provide comparable efficacy and tolerability in the treatment of SAR . Both treatments are significantly more effective than placebo BACKGROUND This is the first prospect i ve , r and omized , double-blind , placebo-controlled study showing statistical improvement of an H(1)-antihistamine in children with seasonal allergic rhinitis in all symptoms throughout the entire treatment period . OBJECTIVE This r and omized , placebo-controlled , parallel-group , double-blind study was performed to assess the efficacy and safety of fexofenadine in children with seasonal allergic rhinitis . METHODS This study was conducted at 148 centers in 15 countries . Nine hundred thirty-five children ( aged 6 - 11 years ) were r and omized and treated with either fexofenadine HCl 30 mg ( n = 464 ) or placebo ( n = 471 ) tablets twice a day for 14 days . Individual symptoms ( sneezing ; rhinorrhea ; itchy nose , mouth , throat , and /or ears ; itchy , watery , and /or red eyes ; and nasal congestion ) were assessed at baseline and then daily at 7:00 AM and 7:00 PM ( + /-1 hour ) during the double-blind treatment period . Each total symptom score was the sum of all symptoms , excluding nasal congestion . The primary efficacy variable was the change from baseline in the average of the daily 12-hour evening reflective total symptom scores throughout the double-blind treatment . Safety was evaluated from adverse-event reporting , vital signs , physical examinations , and clinical laboratory data at screening and study end point . RESULTS Fexofenadine was significantly superior to placebo in the primary efficacy analysis ( P < /=.0001 ) . Individual symptom scores showed statistically significant superiority compared with placebo ( P < .05 ) , including nasal congestion in the evening reflective assessment ( P < .05 ) . There was no significant difference in adverse events between fexofenadine and placebo , either overall or by causality . CONCLUSION The efficacy and safety of the H(1)-antihistamine fexofenadine has been confirmed in this multicenter , multinational study of children aged 6 to 11 years with seasonal allergic rhinitis BACKGROUND H1-receptor antagonists are widely used in the treatment of  allergic skin disorders . OBJECTIVE We sought to evaluate the extent of fexofenadine and diphenhydramine distribution into the skin concomitantly with their peripheral H1-receptor antagonist activity . METHODS In a prospect i ve , r and omized , double-blind , parallel-group study , 7 men received  120 mg of fexofenadine , and 7 received 50 mg of diphenhydramine . Before dosing ; at 1 , 3 , 6 , 9 , and 24 hours after the first dose ; and at 168 hours ( steady-state ) , 12 hours after the seventh and last daily dose , blood sample s and skin punch biopsy specimens were obtained , and epicutaneous tests with histamine phosphate , 1 mg/mL , were performed . RESULTS Fexofenadine  penetrated the skin to a significantly greater extent than diphenhydramine at 6 , 9 , 24 , and 168 hours ( P < or = .05 ) . Maximum skin/plasma ratios of both the H1-antagonists ( 41.3 + /- 7.8 for fexofenadine and 8.1 + /- 4.4 for diphenhydramine ) were obtained at 24 
    Output:
    
When compared with placebo , fexofenadine produced more significant antihistamine effects .
Conclusions Fexofenadine has a positive antihistamine effect , which is probably no worse than the second-generation antihistamines .
Fexofenadine probably has a favorable safety profile , which is more likely better than that of the first-generation antihistamines .
There is lack of data to support that fexofenadine has a better overall safety profile compared to the second-generation antihistamines , however , some presently available evidence on sedative effects and certain aspects of cognitive/psychomotor function favors fexofenadine .