Isoetharine is a beta-2 adrenergic receptor agonist, which was developed by Max Bockmuhl, Gustav Erhart and Leonhard Stein at the Hochst laboratories of I.G. Farbenindustrie in 1934. By binding to beta-2 adrenergic receptors on bronchial cell membranes, isoetharine increases the level of cAMP and thus stimulates the relaxation of smooth-muscle cells, stabilizes mast cells and inhibits histamine release. Isoetharine was approved by FDA for the symptomatic relief of bronchiospasms in patients with chronic bronchitis or emphysema (aerosol and solution for inhalation), however, later on the drug was discontinued.

Isoetharine is a beta-2 adrenergic receptor agonist, which was developed by Max Bockmuhl, Gustav Erhart and Leonhard Stein at the Hochst laboratories of I.G. Farbenindustrie in 1934. By binding to beta-2 adrenergic receptors on bronchial cell membranes, isoetharine increases the level of cAMP and thus stimulates the relaxation of smooth-muscle cells, stabilizes mast cells and inhibits histamine release. Isoetharine was approved by FDA for the symptomatic relief of bronchiospasms in patients with chronic bronchitis or emphysema (aerosol and solution for inhalation), however, later on the drug was discontinued.

Isoxsuprine (used as isoxsuprine hydrochloride) is a drug used as a vasodilator in humans (under the trade name Duvadilan) and equines. Isoxsuprine is a β2 adrenoreceptor agonist that causes direct relaxation of uterine and vascular smooth muscle via β2 receptors. Isoxsuprine it is used in humans for treatment of premature labor, i.e. a tocolytic, and as a vasodilator for the treatment of cerebral vascular insufficiency, Raynaud's phenomenon, and other conditions. Isoxsuprine may increase the heart rate, cause changes in blood pressure, and irritate the GI tract. It should, therefore, be used with caution if combined with other drugs that affect blood pressure, such as sedatives and anesthetic drugs. Isoxsuprine is most commonly used to treat hoof-related problems in the horse, most commonly for laminitis and navicular disease, as its effects as a vasodilator are thought to increase circulation within the hoof to help counteract the problems associated with these conditions.

Protokylol, a sympathomimetic drug has been utilized in general clinical practice as a bronchodilator. Protokylol (brand names Caytine, Ventaire) is a β-adrenergic receptor agonist which was used as a bronchodilator in Europe and the United States.

Isoxsuprine (used as isoxsuprine hydrochloride) is a drug used as a vasodilator in humans (under the trade name Duvadilan) and equines. Isoxsuprine is a β2 adrenoreceptor agonist that causes direct relaxation of uterine and vascular smooth muscle via β2 receptors. Isoxsuprine it is used in humans for treatment of premature labor, i.e. a tocolytic, and as a vasodilator for the treatment of cerebral vascular insufficiency, Raynaud's phenomenon, and other conditions. Isoxsuprine may increase the heart rate, cause changes in blood pressure, and irritate the GI tract. It should, therefore, be used with caution if combined with other drugs that affect blood pressure, such as sedatives and anesthetic drugs. Isoxsuprine is most commonly used to treat hoof-related problems in the horse, most commonly for laminitis and navicular disease, as its effects as a vasodilator are thought to increase circulation within the hoof to help counteract the problems associated with these conditions.

Nylidrin (Buphenine, Arlidin) is a beta-adrenergic agonist. Nylidrin causes peripheral vasodilation, a positive inotropic effect, and increased gastric volume of gastric juice. It is used in the treatment of peripheral vascular disorders and premature labor. In peripheral vascular disorders, Arlidin (nylidrin HCl) increases walking ability and promotes healing of trophic ulcers. Nylidrin hydrochloride acts predominantly by beta-receptor stimulation. Beta stimulation with nylidrin has been demonstrated in a variety of isolated tissues from rabbits, guinea pigs and dogs. It has been shown to dilate arterioles in skeletal muscle and to increase cardiac output in the anesthetized dog and cat and in unanesthetized man. An increase in cerebral blood flow and a decrease in vascular resistance has also been reported. The result of this combination of actions is a greater blood supply to ischemic tissues, with usually minimal change in blood pressure. Arlidin may be of benefit in elderly patients with mild to moderate symptoms that are commonly associated with organic mental disorders. Short-term (3 months’ duration) and long-term (12 months’ duration) clinical studies have demonstrated a modest improvement in ability to perform general activities of daily living, self-care and in a capability for social interactions. The mechanism whereby nylidrin may provide relief of selected symptoms in some elderly patients with organic brain disorders is not known.

Etafedrine, a sympathomimetic agent that acts on the sympathetic receptors of the bronchial tree relaxing spasm in a manner similar to that of ephedrine, is a bronchodilator and a selective β2-adrenoreceptor agonist. Contraction of the guinea pig tracheal chain by acetylcholine or histamine was antagonized by etafedrine with a higher potency then ephedrine but with a lower potency than epinephrine (adrenaline). Etafedrine did not increase heart rate or force of contraction in guinea pig atria. Unlike ephedrine and tyramine, etafedrine did not induce the release of noradrenaline as was demonstrated in vitro in the perfused rabbit heart and instead acted as a selective β2 adrenoreceptor agonist. Etafedrine also belongs to the family of medications called decongestants. It works by narrowing blood vessels in the nasal passages, helping to relieve nasal stuffiness. Etafedrine has been used in pharmaceutical compositions, such as NETHAPRIN Expectorant, Nethaprin Dospan and Dalmacol, useful in the treatment of asthma and other respiratory disorders including chronic bronchitis.

Clenbuterol is agonist of beta2 adrenergic receptor. In some countries it is used as bronchodilator for treatment of asthma, but is not approved in USA. The drug is abused by bodybuilders and athletes for its ability to increase lean muscle mass and to reduce body fat. In 1998 FDA approved the clenbuterol-based Ventipulmin Syrup as a prescription-only drug for treatment of airway obstruction in horses.

Ractopamine is a feed additive to promote leanness in animals raised for their meat. Pharmacologically, it is a TAAR1 agonist and β adrenoreceptor agonist that stimulates β1 and β2 adrenergic receptors. Ractopamine is known to increase the rate of weight gain, improve feed efficiency, and increase carcass leanness in finishing swine. Its use in finishing swine yields about three kilograms of additional lean pork and improves feed efficiency by 10%. Ractopamine is the active ingredient in products known as Paylean for swine and Optaflexx for cattle, developed by Elanco Animal Health, a division of Eli Lilly and Company, for use in food animals for growth promotion. Ractopamine use has been banned in most countries, including the European Union, mainland China and Russia while 27 other countries, such as Japan, the United States, Canada, and South Korea, have deemed meat from livestock fed ractopamine safe for human consumption. Ractopamine is safe for finishing pigs heavier than 240 lb (110 kg) when administered in the diet at concentrations up to 10 ppm and fed for up to 35 days.

Zilpaterol is an agonist of β2-adrenergic receptor. Zilpaterol exerts bronchospasmolytic action. Zilmax® (4.8% Zilpaterol hydrochloride) is used to increase rate of bodyweight gain, improve feed efficiency, and increase carcass leanness in cattle fed in confinement for a period of 20-40 consecutive days at the end of the feeding period before slaughter.