Update on the Use of Leukotriene Modifiers in Asthma
Doctors who treat allergies and asthma regularly are beginning to gain more experience with the use of the Leukotriene Modifiers (trade names Accolate, Singulair, Zyflo). When these drugs were first released, specialists did not know what role these drugs would play in the asthma medicine armamentarium (see article or links on NHLBI asthma guidelines).
Initially, at least, many of us chose to limit the use of these drugs, because the inhaled steroids were much more effective than the Leukotriene Modifiers (LKs). That is, most asthma patients could be controlled quite well on a once or twice daily maintenance regimen of inhaled steroids and as needed bronchodilators. A main concern was (and still is) that the anti-inflammatory properties of LKs were not clearly documented.
There are three issues that have come to make the LKs more attractive. First, there has been some studies showing that moderate to high doses of inhaled steroids may have significant bone effects (i.e. decreased growth velocity in children and osteopenia). Until now we have been successful in lowering inhaled steroid doses by the addition of a long-acting bronchodilator (salmeterol). The attraction of the LKs is that they may also be steroid-sparing (i.e., may enable the further lowering of the inhaled steroid dose when added the inhaled steroid and salmeterol). There have been some preliminary studies that have documented this steroid-sparing with LKs. We must stress, in light of this discussion, that low dose inhaled steroids are still considered to be an extremely safe therapy.
Secondly, studies continue to document the poor compliance with the use of inhaled medications. Patients, unless they are repeatedly trained on the use of inhalers, have difficulty in using these devices correctly. Although the new dry powder devices (e.g. budesonide) have solved some of these technique problems, patients still seem to be more adept and willing to swallow a pill. Compliance is even further enhanced with montelukast (trade name Singulair), which is a once a day preparation. In this regard, the LKs can be very useful as an additional agent in a moderate to severe asthmatics regimen, or as a single agent for the mild asthmatic.
Thirdly, there is the possibility that the LKs may be effective in treating the allergic rhinitis that often accompanies (and can exacerbate) asthma symptoms. Studies are presently underway that look at the effect of these drugs on the symptoms of allergic rhinitis.
In summary, asthma specialists are beginning to gain more experience with the LKs. These drugs can be useful in lowering the dose of inhaled steroids, while maintaining good pulmonary function. At this point, we feel they should be used as a single agent only in the mildest (i.e., near normal pulmonary function) of persistent asthmatics.