▁disease . ▁Norm ally ▁admin ister ed ▁are ▁G n R H ▁analog ues , ▁such ▁as ▁le u pr or elin ▁or ▁cet ror el ix . ▁Although ▁G n R H ▁ag on ists ▁stim ulate ▁the ▁same ▁re cept ors ▁that ▁G n R H ▁does , ▁since ▁they ▁are ▁present ▁continu ously ▁and ▁not ▁in ▁a ▁p uls atile ▁manner , ▁they ▁serve ▁to ▁in hib it ▁the ▁p itu it ary ▁g land ▁and ▁therefore ▁block ▁the ▁whole ▁chain . ▁However , ▁they ▁initially ▁cause ▁a ▁sur ge ▁in ▁activity ; ▁this ▁is ▁not ▁sole ly ▁a ▁theoretical ▁risk ▁but ▁may ▁cause ▁the ▁cancer ▁to ▁f lare . ▁Fl ut am ide ▁was ▁initially ▁used ▁at ▁the ▁beginning ▁of ▁G n R H ▁ag on ist ▁ther apy ▁to ▁block ▁this ▁sur ge , ▁and ▁it ▁and ▁other ▁NS A As ▁continue ▁in ▁this ▁use . ▁In ▁contrast ▁to ▁G n R H ▁ag on ists , ▁G n R H ▁ant agon ists ▁don ' t ▁cause ▁an ▁initial ▁and ro gen ▁sur ge , ▁and ▁are ▁gradually ▁replacing ▁G n R H ▁ag on ists ▁in ▁clin ical ▁use . ▁ ▁There ▁have ▁been ▁studies ▁to ▁investigate ▁the ▁benefit ▁of ▁adding ▁an ▁anti andro gen ▁to ▁surg ical ▁orch ie ct omy ▁or ▁its ▁continued ▁use ▁with ▁a ▁G n R H ▁analog ue ▁( comb ined ▁and ro gen ▁block ade ▁( C AB )). ▁Adding ▁anti and rog ens ▁to ▁orch ie ct omy