Arbutamine was indicated to elicit acute cardiovascular responses in order to aid in diagnosing the presence or absence of coronary artery disease in patients who cannot exercise adequately. Arbutamine is a synthetic catecholamine with positive chronotropic and inotropic properties. The chronotropic (increase in heart rate [HR]) and inotropic (increase in force of contraction) effects of arbutamine serve to mimic exercise by increasing cardiac work (producing stress) and provoke myocardial ischemia in patients with compromised coronary arteries. In functional assays, arbutamine is more selective for beta-adrenergic receptors than for alpha-adrenergic receptors. The beta-agonist activity of arbutamine provides cardiac stress by increasing HR, cardiac contractility, and systolic blood pressure.

Dipivefrin is a prodrug with little or no pharmacologically activity until it is hydrolyzed into epinephrine inside the human eye. The liberated epinephrine, an adrenergic agonist, appears to exert its action by stimulating α -and/or β2-adrenergic receptors, leading to a decrease in aqueous production and an enhancement of outflow facility. The dipivefrin prodrug delivery system is a more efficient way of delivering the therapeutic effects of epinephrine, with fewer side effects than are associated with conventional epinephrine therapy. Dipivefrin is used as initial therapy for the control of intraocular pressure in chronic open-angle glaucoma.

Ritodrine (trade name Yutopar) is beta-2 adrenergic agonist used to stop premature labor. Ritodrine binds to beta-2 adrenergic receptors on the outer membrane of the myometrial cell, activates adenyl cyclase to increase the level of cAMP which decreases intracellular calcium and leads to a decrease of uterine contractions. In addition to stimulating the beta-2–adrenergic receptors of the uterine smooth muscle, ritodrine stimulates beta-adrenergic receptors of bronchial and vascular smooth muscles. The cardiostimulatory effects, including increased cardiac output, increased maternal and fetal heart rates, and widening of the maternal pulse pressure, are probably due to relaxation of the vascular smooth muscle. Relaxation of vascular smooth muscle stimulates the beta-1–adrenergic receptors and the reflex response to blood pressure. Also, during intravenous administration, ritodrine transiently increases maternal and fetal blood glucose and maternal plasma insulin concentrations. Other metabolic changes include increased cAMP, lactic acid, and free fatty acids, and decreased serum potassium concentration. Most side effects of β2 agonists result from their concurrent β1 activity and include the increase in heart rate, rise in systolic pressure, decrease in diastolic pressure, chest pain secondary to myocardial infarction, and arrhythmia. Beta-agonists may also cause fluid retention secondary to decrease in water clearance, which when added to the tachycardia and increased myocardial work, may result in heart failure. In addition, they increase gluconeogenesis in the liver and muscle resulting in hyperglycemia, which increases insulin requirements in diabetic patients. The passage of β agonists through the placenta does occur and may be responsible for fetal tachycardia, as well as hypoglycemia or hyperglycemia at birth.

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.

PHENYRAMIDOL (ANALEXIN®), also known as fenyramidol, is an aminopyridine derivative, used as analgesic and muscle relaxant. It is considered as a drug that possibly causes hepatotoxicity.

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.