***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 
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    Input: Most clinical trials investigating prevention of seasickness with transdermal scopolamine have been short-term , and little information regarding long-term use is available . We report here a double-blind trial conducted on board a flat-bottomed Republic of Singapore Navy vessel of 2,490 tons , sailing in the South China Sea . The trip lasted 26 d , but self- assessment by the 122 adult male participants ( using a simplified scale quantifying the level of seasickness ) was confined to the 18 d spent at sea . We found that the protection rate with transdermal scopolamine was 46 - 57 % , with maximum benefits to inexperienced participants , during the early preadaptation phase , or in rough seas even after adaptation . Unwanted effects were few and generally minor . We concluded that the benefits of Scopoderm were worth exploiting even for long trips in moderate-to-rough seas In two placebo-controlled , double-blind , r and omized trials scopolamine ( 0.3 mg ) alone or combined with ephedrine ( 25 mg ) was tested for its effectiveness in the prevention of seasickness during 24 h at sea and of motion sickness in rotating chair tests in a laboratory . Scopolamine was effective both alone and in combination with ephedrine , which supports the hypothesis on central cholinergic overactivity in the pathogenesis of motion sickness . Ephedrine did not markedly increase the effectiveness of scopolamine . Side-effects were slight and did not disturb the operating ability of the volunteers The effect of transdermally administered scopolamine ( TTS scopolamine ) ( release rate 5 micrograms/h ) and dimenhydrinate ( 100 mg ) was examined on  optovestibular nystagmus in 16 volunteers in a r and omized double-blind trial . A statistically significant decrease in the optokinetic part of nystagmus was observed during all treatments . Most profound reduction was found during treatment with two TTS scopolamine . The vestibular part was reduced by treatment with two TTS scopolamine , only . The results indicate that scopolamine and dimenhydrinate exert their effect in motion sickness by reducing the vestibular and visual influx and by partly inhibiting the integrative functioning of the vestibular nuclei . In their action , the motion sickness drugs seem to assist the cerebellum by diminishing impulses from various orientation reflexes in order to preserve the functional capacity of the central nervous system . Different symptoms in motion sickness seem to arise when the vestibular gain operates beyond the normal range of the cerebellar control mechanisms Space motion sickness has been estimated as affecting between 1/3 and 1/2 of all space flight participants . NASA has at the moment proposed a combination of promethazine and ephedrine ( P/E ) and one of scopolamine and dextroamphetamine ( S/D ) , both given orally , as well as a transdermally applied scopolamine ( TAS ) , as preventive and ameliorative measures . The reported double-blind study , tests the early phase actions and efficacy of the transdermal scopolamine ( Transderm (TM)-V of ALZA Corporation ) and compares these in detail to the oral medications . Motion sickness resistance was tested by st and ardized head movements while accelerating at 0.2 degree/sec2 to a maximum rotation of 240 degrees/sec , with an intermediate plateau of 10 min at 180 degrees/sec . To permit weighting motion sickness protection against other system influences , cardiovascular , psychological ( subjective and objective ) , and visual parameter changes were documented for the three therapeutic modes . The relative impact of the various modalities on operational and experimental components of space missions is discussed . A comparison to intramuscularly administered promethazine ( a backup therapeutic mode suggested for Space Shuttle use ) is also included Summary Three placebo-controlled double-blind studies in healthy volunteers were performed to reveal the psychophysiological effects of scopolamine , ephedrine and their combination . Single intravenous dose of scopolamine 6 µg/kg ( scopolamine hydrobromide 7.4 µg/kg ) impaired various psychomotor functions both subjectively and objective ly . It caused sedation , impairment of coordinative and reactive skills , visual disturbances and impairment of short-term memory .  Oral scopolamine hydrobromide in single doses of 0.3 mg and 0.9 mg , or 0.9 mg b.d . for 3 days , had few effects . A slight impairment of short-term memory and a decrease in the flicker fusion threshold were seen . The visual nearpoint and pupil diameter were increased and some subjects reported blurred vision and dizziness during treatment with scopolamine 0.9 mg b.d . Scopolamine showed clear cardiovascular effects in all studies : it decreased heart rate and systolic blood pressure . Ephedrine alone and in combination with scopolamine had no deleterious effects . On the contrary , it antagonized the scopolamine-induced impairment in the flicker fusion test and the decrease in blood pressure and heart rate . In sufficient doses scopolamine impairs various psychomotor and cognitive skills . An oral dose of scopolamine hydrobromide 0.9 mg on average has few effects , although they may be very striking in certain individuals . To avoid unwanted effects and diminition in performance by scopolamine , doses less than 0.9 mg should be used Treatment of acute motion sickness induced by parabolic flight with a preparation of scopolamine placed in the buccal pouch was investigated . Twenty-one subjects flew aboard a KC-135 aircraft operated by the National Aeronautics and Space Administration ( NASA ) which performed parabolic maneuvers result ing in periods of 0-g , 1-g , and 1.8-g . Each subject flew once with a tablet containing scopolamine and once with a placebo in a r and om order , crossover design . Signs and symptoms of motion sickness were systematic ally recorded during each parabola by an investigator who was blind to the content of the tablet . Compared with flights using placebo , flights with buccal scopolamine result ed in significantly lower scores for nausea ( 31%-35 % reduction ) and vomiting ( 50 % reduction in number of parabolas with vomiting ) . Side effects of the drug during flight were negligible . We conclude that buccal scopolamine is more effective than a placebo in treating ongoing motion sickness The efficacy and tolerability of Scopoderm TTS ( SCOTTS ) , a transdermal system containing scopolamine , were compared with those of the oral antiemetic dimenhydrinate ( double-dummy technique ) in a controlled , double-blind , within-patient study including 20 test persons with proven motion sickness . During a 1-h test flight , SCOTTS proved to be as effective as dimenhydrinate . The efficacy and tolerability of both SCOTTS and dimenhydrinate were assessed as to be equally good . Due to its galenic properties , SCOTTS is effective over a 72-h period and therefore is useful in the prevention of motion sickness during long-distance flights , where it is superior to dimenhydrinate INTRODUCTION Despite many existing treatments , airsickness is an issue of concern for soldiers being transported by helicopter . This experiment examined the efficacy of four airsickness treatments and their effects on performance . This study replicated the transport of soldiers in the cabin of an UH-60 Black Hawk helicopter performing many of the flight maneuvers potentially experienced in a night troop transport during turbulent conditions . METHODS A double-blinded , placebo-controlled design was used to compare the effectiveness of four airsickness counter measures to their placebo controls . There were 64 male , non-aviator subjects ( ages 18 - 34 yr ) who were recruited for the study . Of these , 16 subjects were r and omly assigned to each of 4 groups : ( 1 ) promethazine ( 25 mg ) + caffeine ( 200 mg ) ; ( 2 ) meclizine ( 25 mg ) ; ( 3 ) Scopolamine patch ( 1.5 mg ) ; and 4 ) acustimulation wristb and . Each individual participated twice , once with the treatment and once with placebo . RESULTS The findings indicated that only the combination of promethazine + caffeine showed a statistically significant reduction in nausea and motion sickness severity , and an improvement in reaction time when compared with its placebo control . DISCUSSION Data from this study indicated that of the counter measures tested , promethazine + caffeine was the most effective at reducing airsickness while producing the fewest side effects when compared with its placebo . In addition , this study demonstrated that over-the-counter caffeine can serve as an effective stimulant counterpart to promethazine . This may be a more appealing option than employing scheduled sympathomimetic drugs in a combat environment Objective : Space motion sickness is currently treated pharmacologically with the empiric use of the H1 antihistamine promethazine , but use of this intervention is limited by the side effect of significant sedation . This creates a dilemma , as full cognition is particularly important during the same conditions likely to exacerbate the symptoms of space motion sickness . Using overstimulation of the semicircular canals with a rotary chair as a paradigm for space motion sickness , we evaluated four medications , commonly used for the treatment of terrestrial motion sickness and vertigo , for their efficacy in alleviating the simulated symptoms of space motion sickness . Study Design : R and omized , prospect i ve , double-blind study . Setting : Tertiary referral center . Patients : Healthy male and female volunteers , 18 years of age or older , without history of neurologic or psychiatric disorders , and with no known allergies or any previous adverse reactions to the drugs used . Interventions : Lorazepam 1 mg , meclizine 25 mg , promethazine 25 mg , scopolamine 0.4 mg , or placebo . Main Outcome Measure : The ability of each treatment to control the nausea and vomiting associated with our paradigm for space motion sickness was evaluated by measuring time of rotation pre- and posttreatment and time of symptom onset pre- and posttreatment . Results : Only scopolamine effected a mean change in duration of rotation that reached statistical significance when compared with placebo ( p < 0.008 ) , with a greater than 40 % increase in rotation time . Results with promethazine were not statistically significant . Conclusion : Results showed a rank order of efficacy of scopolamine > promethazine > placebo > meclizine > lorazepam . Scopolamine significantly increased rotation time , but none of the treatments result ed in a significant delay to onset of symptoms Transdermal scopolamine has been reported to provide protection against motion sickness , both while sailing at sea ( 7 - 8 h ) and under experimental conditions . In this study , we tested the efficacy of transdermal scopolamine and evaluated its side effects during a 72-h cruise at sea . We tested 38 male volunteers , 20 - 25 years old , who were located on a 3000-ton vessel . The presence of seasickness , defined by Graybiel 's diagnostic criteria , was used to calculate percent protection . When sickness was considered as malaise II or more , the drug provided 74 , 73 , and 39 % protection during the three sailing days , respectively . There were no significant differences in the magnitude of the side effects reported by experimental and placebo groups . We conclude that transdermal scopolamine 's efficacy against seasickness during a 3-day cruise was not associated with significant side effects and , therefore , we find the drug suitable for long-term use by sailing crews We conducted a double‐blind , placebo‐controlled study to evaluate the efficacy and tolerability of transdermal scopolamine in the prevention of  motion sickness ( MS ) aboard a frigate during 7 days of continuously moderate or heavy seas . Forty‐nine healthy sailors with a previous history of MS were r and omly assigned to receive a transdermal therapeutic system of scopolamine ( TTS‐S ) or transdermal placebo ( TD‐P ) . Patches were placed behind the ears at least 4 hours before departure and were removed 72 hours later . Subjects were observed on days 1 to 4 and 6 . In the TTS‐S group , both subjective feeling of MS and the incidence of nausea were reduced during the first 2 days . Because of adaptation , differences in signs and symptoms of MS between subjects receiving TTS‐S and TD‐P disappeared after the second day . During the first 3 days , vomiting occurred less often in the TTS‐S group . On day 6 , 3 days after removal of the patch , vomiting occurred in 23 % of the TTS‐S group , probably due to delay in adaptation , but none of the subjects in the TD‐P group vomited . Concentration was not adversely influenced , since the ability to work increased in the TTS‐S group . During prolonged continuous exposure to heavy and moderate seas , 2.5 cm2 TTS‐S discs proved to be efficacious in preventing MS , with xerostomia as a tolerable side effect and no significant ocular side effects The effects of transdermally administered scopolamine ( TTS-scopolamine ) ( release rate 5 micrograms/h , one and two patches ) and dimenhydrinate ( 100 mg ) on caloric , angular acceleration induced and optokinetic nystagmus were examined in 16 volunteers in a r and omized double-blind study . All drugs induced a statistically significant decrease in maximum velocity of caloric nystagmus , as compared with placebo . In the rotatory test , two TTS-scopolamine and dimenhydrinate reduced the vestibular gain significantly . No changes were observed in time constant . In the optokinetic test , all dru 
    Output:
    
Studies were generally small in size and of varying quality .Scopolamine was more effective than placebo in the prevention of symptoms .
Comparisons between scopolamine and other agents were few and suggested that scopolamine was superior ( versus methscopolamine ) or equivalent ( versus antihistamines ) as a preventative agent .
Although sample sizes were small , scopolamine was no more likely to induce drowsiness , blurring of vision or dizziness compared to other agents .
Dry mouth was more likely with scopolamine than with methscopolamine or cinnarizine .
The use of scopolamine versus placebo in preventing motion sickness has been shown to be effective .
No conclusions can be made on the comparative effectiveness of scopolamine and other agents such as antihistamines and calcium channel antagonists .