Notes for: Cromoglycate,Rel,Leukotriene AntagonistsLast edited [22/08/2013 16:12:54]
Montelukast and zafirlukast are leukotriene receptor antagonists (LTRA) for use in the management of asthma (not COPD or any other condition). Montelukast is licensed as an adjunctive therapy in the control of mild to moderate and exercise induced asthma and can be used from the age of 6 months. Zafirlukast is licensed for the management of asthma and can be used from the age of 12 years.
There is evidence of modest benefit using LTRAs in mild to moderate asthma. In general their role is an add-on to, but not a substitute for, inhaled steroids ie Steps 3 to 4 of the BTS guidelines. For children aged 2 - 5 years LTRAs may be used at Step 3 as add-on therapy or even at Step 2 if inhaled steroid cannot be used.
LTRAs will not be effective in all patients. It is therefore important that a trial period is undertaken during which clear benefit must be demonstrated before long term therapy is continued. Patients in whom these products may be particularly effective are those with aspirin sensitivity or a large exercise induced component to the symptoms. A successful trial of therapy is identified as a significant reduction in symptoms ie frequency of nocturnal waking, a significant reduction in rescue medication usage, an improvement in peak flow variability to less than 15% or an improvement in FEV1 of greater than 15%. Improvements in peak flow and / or FEV1 are more reliable indicators of a response. If there is no response after a four-week trial consideration should be given to withdrawing LTRA therapy. In therapeutic terms the products can be regarded as identical. Therefore, a lack of success with one should not be followed by a trial of the other.