Pharmacological Management: Long-Acting β2-Adrenergic Agonists
Amy Ly, PharmD, Hannah Y. Mak, PharmD, and Amy Brown, MD, MBe
Introduction
•Long-acting β2-adrenergic agonists (LABAs) (Table 34-1) are used to prevent symptoms of asthma from becoming severe.
•These agents work by stimulating β2-adrenergic receptors in the lungs to open the airways.
•These agents are not used for quick relief of asthma symptoms. See Chapter 33, Pharmacological Management: Short-Acting β2-Adrenergic Agonists, for quick-relief medications.
•Two agents, salmeterol and formoterol, are approved by the U.S. Food and Drug Administration (FDA) for use in children ≥12 years of age.
•Children <12 years of age may be prescribed LABAs by their provider on the basis of recommendations by the National Asthma Education and Prevention program.
| Table 34-1. Long-Acting β2-Adrenergic Agonists | ||
| Drug | Available Dosages | Formulation |
| Fluticasone or salmeterol | 100/50 μg 250/50 μg 500/50 μg | Dry-powder inhaler |
| Fluticasone or salmeterol | 45/21 μg 115/21 μg 230/21 μg | Metered-dose inhaler |
| Budesonide or formoterol | 80/4.5 μg 160/4.5 μg | Metered-dose inhaler |
| Mometasone or formoterol | 100/5 μg 200/5 μg | Metered-dose inhaler |
Mechanism of Action and Pharmacology
•Stimulates β2-receptors in the lungs to relax airway smooth muscle that inhibits bronchoconstriction
•Peak effect: 1–4 hours
•Duration: ≤12 hours; approximately 5 hours with chronic use
—Lipophilicity (“lipid-loving” property) of the drug prolongs the retention of LABAs in the lung tissue
•Systemic absorption is minimal; thus, there is low risk for drug-drug interaction
•Dose-dependent adverse effects include tremor and hyperglycemia
•Powder inhalation contains lactose; use caution in children with severe milk protein allergy
•Monitoring:
—Use of as-needed rescue asthma medications
—Frequency of exacerbations
—Lung function tests (ratio of forced expiratory volume in 1 second [FEV1] to forced vital capacity and FEV1 precentage predicted)
Indications and Administration
•LABAs are not a first-line medication for treatment of asthma. They should be used adjunctively for maintenance control of asthma.
•LABAs are indicated for use in combination with an inhaled corticosteroid (ICS) (fluticasone, budesonide, mometasone) for long-term control and prevention of symptoms in moderate or severe persistent asthma.
•LABAs are not used as monotherapy because they have been shown to increase the risk of asthma-related deaths and carry an FDA black box warning.
•LABAs are indicated in Step 3 care and higher in children ≥5 years old with poorly controlled asthma who are already taking a low to medium dose of ICS as defined by the National Asthma Education and Prevention Program, Expert Panel 3.
•LABAs are ineffective for acute symptoms of asthma.
•The dose should not exceed 100 mg per day for salmeterol or 24 mg per day for formoterol.
•LABAs can be prescribed in several preparations, including a metered-dose inhaler (MDI) and a dry-powder inhaler (DPI).
•The most commonly used preparation for young children is an MDI. When using an MDI, be sure to instruct the patient and caregiver on the proper use and maintenance of a holding chamber, also known as a “spacer” (see Chapter 109, Spacers and Holding Chambers).
•DPIs have the advantage of not requiring a holding chamber; however, the child must be able to develop sufficient inspiratory flow to activate a DPI to deliver sufficient medication. When using a DPI, be sure to instruct the patient to rinse and spit with water each time after inhaling the dose.
is concern whether they will consistently use proper technique on a daily
basis, over time. For this reason, many specialists limit DPIs to children
Resources for Families
•How Is Asthma Treated and Controlled? (National Heart, Lung, and Blood Institute). www.nhlbi.nih.gov/health/health-topics/topics/asthma/treatment
•Treatment: Childhood Asthma (Mayo Clinic). www.mayoclinic.org/diseases-conditions/childhood-asthma/diagnosis-treatment/treatment/txc-20193128.
•Know How to Use Your Asthma Inhaler (U.S. Centers for Disease Control and Prevention). www.cdc.gov/asthma/inhaler_video/default.htm
Clinical Pearls
•LABAs are “controller” medications for asthma and should not be used to treat acute asthma symptoms.
•The use of LABAs is never indicated as monotherapy; LABAs should always used in combination with ICS therapy.
•LABAs are indicated for persistent asthma as a step-up therapy when patients are not able to control symptoms with ICS alone.
•Frequent asthma visits with symptom assessment is important for patients with persistent asthma, especially when it is hard to control. If improvement is noted with an ICS and LABA combination, then steps should be taken to continue to step down the LABA treatment, if the patient tolerates it.
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