What the label lists and what reports show
Formoterol side effects
Formoterol's FDA label: “Most common adverse reactions ( > 2% and more common than placebo) are diarrhea, nausea, nasopharyngitis, dry mouth, vomiting, dizziness, and insomnia ( 6.2 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at …” FAERS holds 4,695 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is dyspnoea (1,312 reports).
- Generic listed
Check it at the source: the formoterol FDA label on DailyMed (effective May 31, 2019, Viatris Specialty LLC); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of PERFOROMIST Inhalation Solution?PERFOROMIST Inhalation Solution can cause serious side effects, including: • people with asthma who take long-acting beta 2 adrenergic agonist (LABA) medicines, such as PERFOROMIST Inhalation Solution, without also using a medicine called an inhaled corticosteroid, have an increased risk of serious problems from asthma, including being hospitalized, needing a tube placed in their airway to help them breathe, or death. • Call your healthcare provider if breathing problems worsen over time while using PERFOROMIST Inhalation Solution. You may need a different treatment. • Get emergency medical care if: • breathing problems worsen quickly • you use your rescue inhaler medicine, but it does not relieve your breathing problems • COPD symptoms that get worse over time. […]
Source: FDA drug label, Viatris Specialty LLC, effective May 31, 2019 (SPL set fb2fe258-fe2e-47f6-8adf-ca75bf6f90af), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions ( > 2% and more common than placebo) are diarrhea, nausea, nasopharyngitis, dry mouth, vomiting, dizziness, and insomnia ( 6.2 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
From the label: adverse reactions, continuedLong-acting beta 2 -adrenergic agonists, such as PERFOROMIST, as monotherapy (without an inhaled corticosteroid) for asthma increase the risk of asthma-related events. PERFOROMIST is not indicated for the treatment of asthma [see WARNINGS AND PRECAUTIONS (5.1) ]. Most common adverse reactions ( > 2% and more common than placebo) are diarrhea, nausea, nasopharyngitis, dry mouth, vomiting, dizziness, and insomnia ( 6.2 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Beta 2 -Agonist Adverse Reaction Profile Adverse reactions to PERFOROMIST Inhalation Solution are expected to be similar in nature to other beta 2 -adrenergic receptor agonists including: angina, hypertension or hypotension, tachycardia, arrhythmias, nervousness, headache, tremor, dry mouth, muscle cramps, palpitations, nausea, dizziness, fatigue, malaise, insomnia, hypokalemia, hyperglycemia, and metabolic acidosis. 6.2 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. …
Source: FDA drug label, Viatris Specialty LLC, effective May 31, 2019 (SPL set fb2fe258-fe2e-47f6-8adf-ca75bf6f90af), via openFDA; the full label on DailyMed
What do FAERS reports show?
4,695 reports list formoterol among the medicines taken, each a report of something that happened, not proof the medicine caused it; 526 are coded as a death and 2,117 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 20 reactions below, 6 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Formoterol: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions