A new, large-scale study shows that levalbuterol, a purified form of the widely used asthma medication albuterol, is effective for children in much smaller doses with fewer side effects than the standard medication. Levalbuterol contains only the biologically active right isomer of albuterol. Albuterols left isomer is inert, at best, and possibly harmful.
Albuterol is the most widely prescribed asthma medication for children, said Henry Milgrom, M.D., senior faculty member at National Jewish Medical and Research Center and lead author of the paper appearing in the December 2001 issue of The Journal of Allergy and Clinical Immunology. It is valuable to have an alternative to the standard formulation, one that can be especially helpful for patients who use their rescue inhalers several times a day and for acute asthma attacks.
Most molecules have two mirror-image forms, known as isomers. Although the left and right isomers have the same chemical composition, they are arranged differently, much like a left hand and a right hand. Anyone who has put a left glove on the right hand can imagine how the two isomers of a single compound might interact differently with other molecules. As a result, they can have vastly different biological effects. Thalidomide is the most famous example; one isomer effectively treats morning sickness, while the other can cause horrible birth defects. Hundreds of medications contain both isomers, only one of which is truly therapeutic.
The standard formulation of albuterol, known as racemic albuterol, contains approximately even amounts of both the left and right isomers. It has been known for years that the right isomer generates all the medications bronchodilatory effect. The left isomer lingers longer in the body, and animal evidence indicates that it actually increases the twitchiness of an asthmatics airways. Its effect in hum
Contact: William Allstetter
National Jewish Medical and Research Center