Effect ofregular terbutaline on theairway responsetoinhaled budesonide

Background - Thereboundincrease in bronchial reactivity andfall inforced expiratory volumeinonesecond(FEVI) followingtreatment withPagonists seenin several studies hasoccurred regardless of concurrent steroid therapy. Little isknown abouttheeffect ofaddingPagonists to corticosteroids, butinarecentstudyregulartreatment withterbutaline appeared toreducesome ofthebeneficial effects ofbudesonide. Theeffects ofbudesonide aloneandincombination withregular terbutaline treatmenton lungfunction, symptomscores, andbronchial reactivity weretherefore examined. Methods- Sixteensubjects withmild stable asthmainhaled budesonide 800pg twicedaily fortwoperiods of14dayswith terbutaline 1000jgthreetimesdailyor placebo inadoubleblindcrossover fashion.FEVyandthedoseofhistamine or adenosine monophosphate (AMP)causing a20%fall inFEV1(PD20) weremeasured beforeand12hoursafter thefinal dose oftreatment, andchanges frombaseline werecompared. Sevendaymeanvalues for daily morning andevening peakexpiratory flow(PEF)values, symptomscores, and rescuemedication werecomparedbefore andduring treatment. Results -Morningandevening PEF rose more withbudesonide plusterbutaline thanwithbudesonide alone, withamean difference of19 /minoccurring inthe evening (95%confidence interval (CI)2to 36).Therewasnodifference insymptom scoresduring treatment. Following treatmentthemeanincrease inFEV, was150ml higher withbudesonide alone(95%CI-10 to300). Therewasnodifference between treatments inchangeinhistamine and AMP PD20. Conclusions - EveningPEF wasgreater whenbudesonide wascombinedwithregularterbutaline. Therewasnoevidence of a difference inbronchial reactivity followingthetwotreatment regimens. The findings ofaprevious studywerenotconfirmedas thereduction inFEV1after budesonide andterbutaline was smaller andnotstatistically significant. Further workisneededtodetermine whetherthis disparity infindings inthetwostudies is duetoatype2statistical errorinthisstudy oraspurious finding intheprevious study. (Thorax 1996;51:989-992)