Isoetharine is a selective short-acting β₂ adrenoreceptor agonist. It can be called the "granddaughter of adrenalin" in the line of β₂ agonists that gave quick relief for bronchospasm and asthma.

Epinephrine Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands and ...

(adrenalin) was the first of these, and next came

isoprenaline Isoprenaline, or isoproterenol (brand name: Isoprenaline Macure), is a medication used for the treatment of bradycardia (slow heart rate), heart block, and rarely for asthma. It is a non-selective β adrenoceptor agonist that is the isopropylam ...

(isoproterenol). Isoetharine was the third drug in this line, thus the third generation or granddaughter of the original. In the western United States, 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 β₂ 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 "β₂ effect" was not quite as selective as might be hoped. β₁ receptors appeared to also be stimulated in some patients, causing cardiac and other CNS side effects. With isoetharine 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. By the late 1980s, isoetharine was largely replaced by

orciprenaline Orciprenaline, also known as metaproterenol, is a bronchodilator used in the treatment of asthma. Orciprenaline is a moderately selective β2 adrenergic receptor agonist that stimulates receptors of the smooth muscle in the lungs, uterus, and v ...

(metaproterenol), which seemed to have slightly less cardiac side effect and lasted a couple of hours longer. Orciprenaline in turn was replaced by

salbutamol Salbutamol, also known as albuterol and sold under the brand name Ventolin among others, is a medication that opens up the medium and large airways in the lungs. It is a short-acting β2 adrenergic receptor agonist which works by causing rel ...

(albuterol). Some practitioners still believe that these later aerosolized bronchodilators never gave quite as quick of relief from asthmatic shortness of breath as did isoetharine. Thus they see a continued specialty role in treatment of severe shortness of breath that does not improve in the first five minutes of salbutamol treatment.

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