What is the recommended treatment for exercise-induced asthma?

Treatment of Exercise-Induced Asthma

For all patients with exercise-induced bronchoconstriction (EIB), administer an inhaled short-acting β2-agonist (SABA) such as albuterol 15 minutes before exercise as first-line therapy. 1, 2

First-Line Treatment: Pre-Exercise SABA

• Inhaled SABAs (albuterol, levalbuterol) taken 15 minutes before exercise provide 80-95% protection for 2-4 hours and are the most effective single intervention for preventing EIB. 1, 2
• SABAs work by relaxing airway smooth muscle and preventing mast cell degranulation, with onset of action within 5 minutes. 1
• SABA use should remain intermittent—less than daily on average, ideally less than 4 times per week—to prevent tolerance development. 1, 2
• Always have a rescue SABA inhaler available during exercise for breakthrough symptoms. 1, 3

Critical Caveat About SABA Frequency

• If you require daily or more frequent SABA use for EIB prevention, this signals inadequate control and necessitates adding a daily controller medication. 1
• A controller agent is generally added whenever SABA therapy is used daily or more frequently. 1

Second-Line Options: Daily Controller Therapy

When symptoms persist despite pre-exercise SABA or when SABA is needed daily or more frequently, add one of the following:

Option 1: Daily Inhaled Corticosteroid (ICS)

• Daily ICS is strongly recommended as the preferred controller for patients with persistent EIB symptoms. 1, 2
• It may take 2-4 weeks after initiation to see maximal improvement. 1
• Do NOT use ICS only before exercise—it must be taken daily to be effective. 1
• ICS addresses the underlying airway inflammation that drives EIB. 1

Option 2: Daily Leukotriene Receptor Antagonist (LTRA)

• Daily montelukast (10 mg for adults ≥15 years) provides 50-60% protection for up to 24 hours and is strongly recommended as an alternative controller. 1, 2, 3
• Montelukast should be taken at least 2 hours before exercise for EIB prevention. 3
• If already taking montelukast daily for chronic asthma, do NOT take an additional dose for exercise—the daily dose provides continuous protection. 3
• LTRAs do not cause tolerance with regular use, unlike β2-agonists. 4, 5
• Important FDA warning: Montelukast carries risk of neuropsychiatric side effects including agitation, depression, suicidal thoughts, and sleep disturbances—counsel patients to report mood or behavior changes immediately. 3

Clinical Decision Between ICS and LTRA

• In clinical practice, the choice between daily ICS and daily LTRA is made case-by-case based on patient preferences, baseline lung function, and side effect profile. 1
• Both provide comparable long-term protection when used daily. 1, 5

Option 3: Pre-Exercise Mast Cell Stabilizer

• Cromolyn sodium or nedocromil taken before exercise provides 50-60% protection for 1-2 hours and is strongly recommended as an alternative. 1, 2
• These agents have the advantage of no tolerance development and can be used multiple times daily without significant adverse effects. 4
• They are less effective than SABAs but can be combined with them. 1, 4

Option 4: Pre-Exercise Anticholinergic

• Ipratropium bromide before exercise is a weak recommendation with low-quality evidence, playing only a secondary role. 1

Critical Safety Warning: Avoid LABA Monotherapy

Never use long-acting β2-agonists (LABAs) such as salmeterol as single therapy for EIB due to serious safety concerns including increased risk of asthma-related deaths, hospitalizations, and intubations. 1, 2, 6

• LABAs must only be prescribed in fixed-dose combination with inhaled corticosteroids (e.g., fluticasone/salmeterol). 6
• Daily LABA use causes tolerance to the protective effect against EIB within days to weeks. 1, 4

Non-Pharmacologic Interventions

All patients with EIB should incorporate these strategies regardless of medication use:

• Perform interval or combination warm-up exercise for 10-15 minutes before planned vigorous activity to induce a refractory period lasting up to 3 hours. 1, 2, 7
• In cold weather, wear a mask or scarf over the mouth and nose to warm and humidify inspired air. 1, 2, 7
• Improve general aerobic conditioning, which reduces baseline airway reactivity. 8
• Avoid exercising in high-pollution environments or during peak allergen exposure if allergic. 7

Dietary Modifications (Weak Evidence)

• Consider a low-salt diet (weak recommendation). 1
• Consider fish oil supplementation (weak recommendation). 1
• Consider ascorbic acid (vitamin C) supplementation (weak recommendation). 1
• Do NOT recommend lycopene supplementation. 1

Special Considerations for Patients with Allergies

• For patients with EIB and documented allergies who have persistent symptoms despite SABA, consider adding an antihistamine. 1
• Do NOT use antihistamines in patients with EIB who do not have allergies—this is strongly recommended against. 1

Treatment Algorithm Summary

1. Start with pre-exercise SABA (15 minutes before) for all patients 1, 2
2. If SABA needed daily or more, OR symptoms persist despite SABA, add:
   • Daily ICS (preferred for underlying asthma) 1, 2, OR
   • Daily LTRA (montelukast) 1, 2, 3, OR
   • Pre-exercise mast cell stabilizer 1, 2
3. Always incorporate warm-up exercise and cold-weather protection 1, 2, 7
4. Never use LABA as monotherapy 1, 2, 6
5. Always have rescue SABA available during exercise 1, 3

Common Pitfalls to Avoid

• Do not use ICS only before exercise—it requires daily dosing for 2-4 weeks to achieve maximal effect. 1
• Do not take an additional dose of montelukast within 24 hours of the previous dose. 3
• Do not ignore increasing SABA use—this signals need for controller therapy escalation. 1
• Do not prescribe LABAs without ICS due to serious safety concerns. 1, 6
• Do not assume all respiratory symptoms during exercise are EIB—confirm diagnosis with objective testing (≥10% fall in FEV1 post-exercise). 7, 9