What do systematic reviews say?

Regular formoterol vs regular salmeterol

Regular formoterol showed no clear difference in asthma‐related SAEs in adults compared with regular salmeterol (low certainty).

• Regular treatment with formoterol versus regular treatment with salmeterol for chronic asthma: serious adverse events 2012 · Cochrane Headline outcomes only
  OR 0.86 [0.29, 2.57]
  3 studies · 1116 participants
  Low