FORMOTEROL FUMARATE
Clinical safety rating: safe
Other adrenergic drugs can have additive cardiovascular effects Can cause paradoxical bronchospasm and increase the risk of asthma-related death.
Formoterol fumarate is a long-acting beta2-adrenergic receptor agonist (LABA) that stimulates intracellular adenyl cyclase, increasing cyclic AMP, leading to relaxation of bronchial smooth muscle, inhibition of mediator release, and increased ciliary motility.
| Metabolism | Primarily metabolized by direct glucuronidation and O-demethylation via CYP2D6 and CYP2C19, with minor contribution from CYP2C9. Further metabolism involves conjugation to inactive metabolites. Formoterol is a substrate for the uptake transporter OCT1. |
| Excretion | Renal: 60% (unchanged and metabolites), Biliary/Fecal: 40% |
| Half-life | Terminal elimination half-life: 10-14 hours; clinically, steady-state achieved within 2-3 days |
| Protein binding | 61-64% bound to albumin and alpha-1-acid glycoprotein |
| Volume of Distribution | 3-4 L/kg (large Vd indicating extensive tissue distribution) |
| Bioavailability | Inhalation: ~50% (lung deposition); oral: negligible due to first-pass metabolism |
| Onset of Action | Inhalation: 1-3 minutes; maximal bronchodilation at 1-2 hours |
| Duration of Action | 12 hours; recommended dosing every 12 hours; prolonged effect due to receptor binding |
Inhalation: 12 mcg every 12 hours; maximum 24 mcg/day.
| Dosage form | SOLUTION |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | Child-Pugh Class A and B: no adjustment; Child-Pugh Class C: use with caution, consider lower doses (e.g., 12 mcg once daily). |
| Pediatric use | Children 5 years and older: 12 mcg inhalation every 12 hours; maximum 24 mcg/day. Safety and efficacy for children under 5 years not established. |
| Geriatric use | No specific dosage adjustment; use the lowest effective dose and monitor for adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Other adrenergic drugs can have additive cardiovascular effects Can cause paradoxical bronchospasm and increase the risk of asthma-related death.
| FDA category | Animal |
| Breastfeeding | It is unknown if formoterol is excreted in human breast milk; however, other beta-2 agonists are present in low levels. The M/P ratio is not established for formoterol. Due to low oral bioavailability, transfer to infant via milk is unlikely to cause significant effects. Caution is advised; manufacturer recommends use only if clearly needed. |
| Teratogenic Risk |
■ FDA Black Box Warning
LABAs increase the risk of asthma-related death. Therefore, formoterol should only be used in asthma patients as add-on therapy to a long-term asthma controller medication (e.g., inhaled corticosteroid) and not as monotherapy.
| Common Effects | COPD |
| Serious Effects |
["Status asthmaticus","Acute deterioration of asthma or COPD","Hypersensitivity to formoterol or any component","Monotherapy for asthma without concomitant inhaled corticosteroid"]
| Precautions | ["Increased risk of asthma-related death with LABA monotherapy","Severe asthma exacerbations and hospitalization","Cardiovascular effects (e.g., tachycardia, hypertension, QT prolongation)","Hypokalemia, hyperglycemia","Paradoxical bronchospasm","Immediate hypersensitivity reactions (e.g., urticaria, angioedema)","Worsening of asthma or COPD symptoms"] |
| Food/Dietary |
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| Formoterol fumarate is a beta-2 adrenergic agonist. Animal studies have shown no evidence of teratogenicity at clinically relevant doses. In humans, there are limited data; however, beta-agonists are generally considered low risk during pregnancy. No increased risk of major malformations has been reported with formoterol use in the first trimester. Use in late pregnancy may theoretically cause uterine relaxation or maternal tachycardia, but no specific teratogenic effects are established. Overall, risk is minimal. |
| Fetal Monitoring | Monitor maternal heart rate, blood pressure, and signs of tocolysis or uterine relaxation. In late pregnancy, monitor fetal heart rate and uterine contractions if used near term. No routine fetal monitoring is mandated, but maternal respiratory status should be assessed. |
| Fertility Effects | No evidence of impaired fertility in animal studies. In humans, no specific effects on fertility have been reported. |
| No significant food interactions. Avoid excessive caffeine intake as it may increase the risk of cardiac stimulation (tachycardia, palpitations). High-fat meals may delay absorption but not clinically significant. Maintain adequate potassium intake; hypokalemia may increase risk of arrhythmias. |
| Clinical Pearls | Formoterol fumarate is a long-acting beta2-agonist (LABA) indicated for maintenance treatment of asthma and COPD, not for acute bronchospasm. Onset of action within 1-3 minutes, maximum effect at 2 hours, duration up to 12 hours. Not a substitute for inhaled corticosteroids; must be used with anti-inflammatory therapy in asthma. Contraindicated as monotherapy in asthma without concurrent ICS. Risk of asthma-related death with LABA monotherapy. Monitor for paradoxical bronchospasm, cardiovascular effects (tachycardia, arrhythmias), and hypokalemia. Tolerance to bronchodilator effect may develop over time. |
| Patient Advice | Do not use formoterol for sudden asthma attacks; use a rescue inhaler (e.g., albuterol) instead. · This medication is for long-term control; use it every 12 hours as prescribed, even if you feel well. · Do not exceed prescribed dose; using more can cause dangerous heart effects. · Rinse mouth after inhalation to prevent oral thrush. · Seek immediate medical help if you experience worsening breathing, chest pain, or rapid heartbeat. · Carry a rescue inhaler at all times. · Do not stop taking your inhaled corticosteroid when using formoterol. · Store capsules in blister pack; use immediately after opening; do not swallow capsules. |