What do systematic reviews say?

Regular formoterol vs regular salmeterol

Regular formoterol showed no clear difference in all‐cause 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 0.77 [0.46, 1.28]
  3 studies · 1116 participants
  Low