Treatment strategies to manage exercise-induced asthma

Drugs that reduce airway inflammation, inhibit the release of mediators or inhibit the contractile effects of these mediators can be used to manage exercise-induced asthma.³⁵

• Inhaled corticosteroids (ICS): have been shown to significantly reduce the severity of exercise-induced asthma and completely inhibit exercise-induced asthma in 50% of cases following 8-12 weeks treatment.^4,9,36,37,11 Sodium cromoglycate, nedocromil sodium or a bronchodilator can be used immediately before exercise (or as rescue medication) until the full effect of ICS is realised. This ICS alone approach is suggested for asthmatics with normal lung function for whom a bronchodilator is not indicated. It is recommended because successful treatment results in 50% of people no longer having exercise-induced asthma and thus the need for pre-exercise medication is avoided.
• Long-acting beta₂ agonist (LABA) in combination with ICS: can be used successfully for prevention of exercise-induced asthma in patients with abnormal spirometry and/or more persistent symptoms.³⁷ The duration of the protective effect of the LABA against exercise induced asthma is reduced when they are taken daily, even in combination with ICS.^35,37-41 As a result of this reduction in duration of protection, it would be expected that over time patients will use extra inhalations of SABA before exercise or if breakthrough exercise-induced asthma occurs.
• Long-acting beta2 agonist (LABA) alone: can be used successfully for prevention of exercise-induced asthma.^42-44 LABAs can be effective for up to 12 hrs when they are used intermittently (less than 3 times a week)⁴⁵ but the duration of the protective effect is reduced when these drugs are used daily.^39,46,47 Further, recovery time from breakthrough exercise-induced asthma can be prolonged when LABA are used daily.⁴¹
• Short-acting beta₂ agonist (SABA): provide about 80% protection for up to 2 hrs when given immediately before exercise.^48,43 SABAs are also effective rescue therapy provided they are not being used to excess. Single-dose LABA or SABA treatment can be beneficial, particularly in young people with normal lung function and no other significant asthma symptoms.
• Sodium cromoglycate and nedocromil sodium: are less effective than beta agonists in preventing exercise-induced asthma. They provide 50-60% protection for only 1-2 hours, but have some advantages over beta₂ agonists.^49-51 They do not induce tolerance and can be used several times in a day. The dose can be adjusted and the protective effect is immediate.⁵²
• Leukotriene receptor antagonists: are also used to control exercise-induced asthma and provide 50-60% protection when given as tablets for up to 24 hrs.^53,54 They do not induce tolerance^55,47 and recovery from any residual exercise-induced asthma is rapid, usually occurring within 15 minutes.^53,41

ICS treatment for 8-12 weeks reduces severity of exercise-induced asthma and after treatment 50% of people will no longer require medication pre-exercise. (II) Single doses of short- or long-acting beta2 agonist, sodium cromoglycate or nedocromil sodium may significantly inhibit or even prevent exercise-induced asthma when taken immediately before exercise. (I) LABAs are best used intermittently to prevent exercise-induced asthma because the duration of their protection against exercise is reduced when they are taken daily, whether alone or in combination with inhaled corticosteroids. (II) Leukotriene antagonists reduce severity and duration of exercise-induced asthma. Tolerance does not develop to daily use of these drugs. (II)

Content Created (Thursday, 16 November 2006)