Is a formoterol (long-acting beta2-adrenergic receptor agonist) inhaler safe to use during pregnancy?

Formoterol Inhaler Safety During Pregnancy

Formoterol inhaler is probably safe to use during pregnancy, especially if the woman was well-controlled on this medication before pregnancy. 1, 2

Safety Profile of Formoterol

• Limited human data exists on formoterol use during pregnancy, but animal data suggest low risk 1
• The pharmacologic and toxicologic profiles of long-acting beta2-agonists (LABAs) like formoterol are similar to short-acting beta2-agonists, which have extensive safety data during pregnancy 1
• If a woman was well-controlled on formoterol before pregnancy, it is acceptable to continue the same medication during pregnancy 1, 2
• FDA pregnancy information indicates that animal studies with formoterol showed potential risks only at extremely high oral doses (730-29,000 times the maximum recommended human dose) 3
• No teratogenic effects were observed in animal studies at inhalation doses up to approximately 300 times the maximum recommended human dose 3

Risk-Benefit Assessment

• The risks of poorly controlled asthma during pregnancy significantly outweigh potential medication risks 1, 2, 4
• Uncontrolled asthma can lead to maternal hypoxia with adverse effects on the fetus 1, 4
• Maintaining good asthma control during pregnancy is critical for maternal and fetal well-being 2, 4

Recommendations for Clinical Practice

• For moderate persistent asthma, a combination of low-dose inhaled corticosteroid (ICS) and LABA is a preferred treatment option 1
• While salmeterol has historically been preferred due to longer experience during pregnancy, continuing formoterol is acceptable if the patient was previously well-controlled 1, 2
• Use the lowest effective dose necessary to maintain asthma control 2
• Regular monitoring of asthma symptoms is recommended throughout pregnancy 2
• Exacerbations during pregnancy should be managed aggressively due to potential fetal risks 2

Common Pitfalls to Avoid

• Discontinuing asthma medications during pregnancy due to unfounded safety concerns can lead to poor asthma control and increased risks to mother and fetus 2, 4
• Failing to aggressively manage asthma exacerbations during pregnancy can lead to maternal hypoxia and adverse fetal outcomes 1, 2
• Switching from formoterol to another LABA unnecessarily if the patient was previously well-controlled on formoterol 1, 2

Special Considerations

• If using formoterol with an ICS (as is typically recommended), budesonide is the preferred ICS during pregnancy with the most safety data 2, 5
• Formoterol should be administered with caution to patients being treated with monoamine oxidase inhibitors, tricyclic antidepressants, or drugs known to prolong the QTc interval 3
• Beta-blockers may inhibit the effect of formoterol when administered concurrently 3