Formoterol

Long-acting selective β2-agonist with rapid onset (rapid-onset LABA)

ATC code: R03AC13 (Formoterol)

Brand names

Foradil, Perforomist

Mechanism of action

Selective β2-adrenoceptor agonist of bronchial smooth muscle. Lower lipophilicity than salmeterol gives a rapid onset – 3–5 minutes after inhalation – while keeping a 12-hour duration. This profile allowed ICS+formoterol (Symbicort, Fostair) to enter the 2024 MART/SMART regimen: a single inhaler serves as both controller and reliever as needed. Activates adenylyl cyclase, raises cAMP, relaxes smooth muscle and suppresses mediator release.

Indications

Asthma

First line

In asthma formoterol is used only combined with an inhaled corticosteroid. 2024 recommends ICS-formoterol (Symbicort, Fostair, Duoresp) in MART/SMART from step 1: a single inhaler used as needed for symptoms acts as both controller and reliever. The rapid onset (3–5 minutes) lets formoterol replace SABA in the reliever role. Isolated formoterol monotherapy in asthma is not used: the same risks described for salmeterol in the SMART trial apply. If formoterol was prescribed without an ICS as a stand-alone long-acting bronchodilator in asthma, consider seeking a second opinion.

Sources

Chronic obstructive pulmonary disease

First line

LABA for COPD maintenance. 2024 and GesEPOC 2024 list formoterol as an option in group B and in LABA+LAMA combinations for frequent exacerbations. Nebulised use (Perforomist, Brovana) is available for patients who cannot manage MDI or dry-powder inhalers.

Sources

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Athletic endurance

Not recommended

Formoterol is used off-label by athletes and fitness influencers for «endurance gains» via β2-receptor stimulation. The hypothetical anabolic and metabolic effect in people without asthma is not supported by quality data. WADA 2024 lists formoterol as prohibited but allows inhalations up to 54 mcg/day with urine peak below 40 ng/mL (TUE with documented asthma). Biohacking above these limits produces tachycardia, tremor, hypokalaemia and arrhythmias. If formoterol is suggested without an asthma diagnosis to «improve cardio», consider seeking a second opinion.

Sources

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Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMA

Spanish Medicines Information Centre (CIMA)

Label dated: 12/30/2025

FDA / DailyMed

FDA — DailyMed Drug Labels

Label dated: 05/01/2026

Safety

Boxed warning

Long-acting beta2-agonists (LABA), including formoterol, increase the risk of asthma-related death when used as monotherapy without an inhaled corticosteroid. In asthma formoterol is used only in fixed combination with an ICS. FDA Black Box 2010, AEMPS issued a parallel warning.

Contraindications

Hypersensitivity to formoterol or excipients
Monotherapy for asthma without inhaled corticosteroid
Tachyarrhythmias

Serious adverse effects

Paradoxical bronchospasm
Severe hypokalaemia
QT prolongation and arrhythmias
Hyperglycaemia
Anaphylactic reactions

Common adverse effects

Tremor
Headache
Palpitations
Throat irritation
Muscle cramps

PregnancyFDA C

FDA Category C. GEMA 5.4 allows continued ICS+formoterol during pregnancy: asthma control outweighs the theoretical risk. Isolated LABA monotherapy is not used in pregnancy, as outside it.

Breastfeeding

Compatible. Hale L2. Inhaled systemic bioavailability is low; only minimal amounts reach milk.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Formoterol used for?

Formoterol is evaluated for the following indications with varying evidence strength: Asthma (evidence tier A), Chronic obstructive pulmonary disease (evidence tier A), Athletic endurance (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Formoterol?

Common side effects of Formoterol (≥ 1 in 100): Tremor, Headache, Palpitations, Throat irritation, Muscle cramps. See the Safety section for uncommon and serious reactions.

Is Formoterol safe during pregnancy?

FDA category C. FDA Category C. GEMA 5.4 allows continued ICS+formoterol during pregnancy: asthma control outweighs the theoretical risk. Isolated LABA monotherapy is not used in pregnancy, as outside it.

Is Formoterol compatible with breastfeeding?

Compatible. Hale L2. Inhaled systemic bioavailability is low; only minimal amounts reach milk.

Who should not take Formoterol?

Formoterol is contraindicated in: Hypersensitivity to formoterol or excipients; Monotherapy for asthma without inhaled corticosteroid; Tachyarrhythmias. Full list in the Safety section.

Does Formoterol carry an FDA boxed warning?

Mechanism of action

Indications

Asthma

First line

Sources

Chronic obstructive pulmonary disease

First line

Sources

Safety

Boxed warning

Contraindications

Hypersensitivity to formoterol or excipients
Monotherapy for asthma without inhaled corticosteroid
Tachyarrhythmias

Serious adverse effects

Paradoxical bronchospasm
Severe hypokalaemia
QT prolongation and arrhythmias
Hyperglycaemia
Anaphylactic reactions

Common adverse effects

Tremor
Headache
Palpitations
Throat irritation
Muscle cramps

PregnancyFDA C

FDA Category C. GEMA 5.4 allows continued ICS+formoterol during pregnancy: asthma control outweighs the theoretical risk. Isolated LABA monotherapy is not used in pregnancy, as outside it.

Breastfeeding

Compatible. Hale L2. Inhaled systemic bioavailability is low; only minimal amounts reach milk.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Formoterol used for?

What are the side effects of Formoterol?

Common side effects of Formoterol (≥ 1 in 100): Tremor, Headache, Palpitations, Throat irritation, Muscle cramps. See the Safety section for uncommon and serious reactions.

Is Formoterol safe during pregnancy?

Is Formoterol compatible with breastfeeding?

Compatible. Hale L2. Inhaled systemic bioavailability is low; only minimal amounts reach milk.

Who should not take Formoterol?

Formoterol is contraindicated in: Hypersensitivity to formoterol or excipients; Monotherapy for asthma without inhaled corticosteroid; Tachyarrhythmias. Full list in the Safety section.

Does Formoterol carry an FDA boxed warning?