Isoetarine (INN) or isoetharine (USAN), trade names Bronkosol and Bronkometer, is a selective beta2-adrenergic receptor agonist. It can be called the "granddaughter of adrenalin" in the line of beta-two antagonists that gave quick relief for bronchospasm and asthma. Adrenalin or epinephrine was the first of these, and next came Isuprel. Isoetharine was the third drug in this line, thus the third generation or granddaughter of the original.
In the western US it was the drug of choice in the late 1970s and early 1980s for nebulization ("breathing treatment") to relieve airway spasm. It generally gave sharp relief of shortness of breath, starting within two to five minutes after the patient began breathing the nebulized mist. This rapid onset is not as clearly present in later drugs.
All of the early beta-two agonist catecholamines used for bronchospasm had strong side effects, with increase in heart rate as the most common and most problematic. This came because its "beta-two effect" was not quite as selective as might be hoped. Beta-one receptors appeared to also be stimulated in some patients, causing cardiac and other CNS side effects. With Bronkosol this effect tended to be transient and usually went away within a matter of minutes after the end of the treatment. Increase in blood pressure also occurred in a small but significant percentage of cases, but also was almost invariably transient.