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.

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.

Fenoterol is a beta2-adrenoreceptor agonist, used as a bronchodilator for the treatment and prevention of bronchospasms, associated with asthma and chronic obstructive airway disease, including bronchitis and pulmonary emphysema. Fenoterol is also used for tocolysis during premature labor. Marketing of fenoterol for treatment of asthma was suspended in Australia and New Zealand because of an increased risk of deaths, most likely due to excessive self-administration of the drug.

Etilefrine is a cardiac stimulant used as an antihypotensive. Intravenous infusion of this compound increases cardiac output, stroke volume, venous return and blood pressure in man and experimental animals, suggesting stimulation of both α and β adrenergic receptors. However, in vitro studies indicate that etilefrine has a much higher affinity for β1 (cardiac) than for β2 adrenoreceptors. Intravenous etilefrine increases the pulse rate, cardiac output, stroke volume, central venous pressure and mean arterial pressure of healthy individuals. Marked falls in pulse rate, cardiac output, stroke volume and peripheral bloodflow, accompanied by rises in mean arterial pressure, occur when etilefrine is infused after administration of intravenous propranolol 2,5 mg. These findings indicate that etilefrine has both β1 and α1 adrenergic effects in man. The French Health Products Agency concluded that etilefrine and heptaminol have an unfavourable harm-benefit balance, and also placed restrictions on the use of midodrine.

Fenoterol is a beta2-adrenoreceptor agonist, used as a bronchodilator for the treatment and prevention of bronchospasms, associated with asthma and chronic obstructive airway disease, including bronchitis and pulmonary emphysema. Fenoterol is also used for tocolysis during premature labor. Marketing of fenoterol for treatment of asthma was suspended in Australia and New Zealand because of an increased risk of deaths, most likely due to excessive self-administration of the drug.

Practolol is a beta-adrenergic antagonist that has been used in the emergency treatment of cardiac arrhythmias. Practolol is a cardio-selective beta-blocking agent with an intrinsic sympathomimetic action, but devoid of local anaesthetic effect. It has been found effective in post infarction arrhythmias. In early infarction it reduces the area of necrosis as measured by surface ST segment mapping. Practolol has also been shown to be an effective drug in treating angina. Long-term treatment revealed advantageous effects of practolol on the incidence of anginal attacks and the number of nitroglycerin tablets consumed in daily life. There was also a noticeable improvement in the ECG. The results obtained in a double-blind trial, with placebo, proved the effectiveness of the drug. The treatment enabled the patients to lead appreciably more active lives. A marked increase in work performance, depending on the dose applied, was confirmed in exercise tolerance tests. No side-effects which would call for discontinuance of the treatment were seen during long-term administration with doses up to 800 mg daily. Like other beta-adrenergic antagonists, practolol competes with adrenergic neurotransmitters such as catecholamines for binding at sympathetic receptor sites. Practolol binds at beta(1)-adrenergic receptors in the heart and vascular smooth muscle, inhibiting the effects of the catecholamines epinephrine and norepinephrine and decreasing heart rate, cardiac output, and systolic and diastolic blood pressure. Practolol, discovered in 1966, was removed from the market due to severe side effects including conjunctival scarring, fibrosis, and metaplasia.

Practolol is a beta-adrenergic antagonist that has been used in the emergency treatment of cardiac arrhythmias. Practolol is a cardio-selective beta-blocking agent with an intrinsic sympathomimetic action, but devoid of local anaesthetic effect. It has been found effective in post infarction arrhythmias. In early infarction it reduces the area of necrosis as measured by surface ST segment mapping. Practolol has also been shown to be an effective drug in treating angina. Long-term treatment revealed advantageous effects of practolol on the incidence of anginal attacks and the number of nitroglycerin tablets consumed in daily life. There was also a noticeable improvement in the ECG. The results obtained in a double-blind trial, with placebo, proved the effectiveness of the drug. The treatment enabled the patients to lead appreciably more active lives. A marked increase in work performance, depending on the dose applied, was confirmed in exercise tolerance tests. No side-effects which would call for discontinuance of the treatment were seen during long-term administration with doses up to 800 mg daily. Like other beta-adrenergic antagonists, practolol competes with adrenergic neurotransmitters such as catecholamines for binding at sympathetic receptor sites. Practolol binds at beta(1)-adrenergic receptors in the heart and vascular smooth muscle, inhibiting the effects of the catecholamines epinephrine and norepinephrine and decreasing heart rate, cardiac output, and systolic and diastolic blood pressure. Practolol, discovered in 1966, was removed from the market due to severe side effects including conjunctival scarring, fibrosis, and metaplasia.

Carazolol is a beta1/beta2 adrenoreceptor blocking agent. Activity and safety of the drug were evaluated in clinical trials that were conducted in healthy subjects and in patients suffering from either chronic bronchitis or asthma. The drug, however, was not developed for human use. Instead, carazolol is used in to reduce stress in animals during transportation. In veterinary medicine, carazolol is given by intramuscular injection to pigs is indicated in stress-inducing situations. In cattle, carazolol is intended to be used for the prevention of shipment stress caused by transportation and formation of new herds.

Betaxolol is a competitive, beta(1)-selective (cardioselective) adrenergic antagonist. Betaxolol is used to treat hypertension, arrhythmias, coronary heart disease, glaucoma, and is also used to reduce non-fatal cardiac events in patients with heart failure. (R)-Betaxolol (Dextrobetaxolol) is the R-isomer of Betaxolol (B328000), a cardioselective β1-adrenergic blocker. It is also an antihypertensive and antiglaucoma agent. Dextrobetaxolol had a much weaker affinity at both b1 and b2 receptors than levobetaxolol. Levobetaxolol (Kb=6 nM at b1 and Kb=39 nM at b2 receptors) more potently inhibited functional activities in cells expressing human recombinant b1 and b2 receptors than dextrobetaxolol (Kb=350 and 278 nM, respectively). Likewise, levobetaxolol was a more potent antagonist in isolated tissues than dextrobetaxolol. In functional assays in cultured human NPE cells levobetaxolol (Ki =16.4 nM) was a potent antagonist of isoproterenol-induced cAMP production with dextrobetaxolol (Ki =2.9 uM) being considerably weaker than the latter antagonist. In ocular hypertensive cynomolgus monkeys, levobetaxolol was more effective at reducing IOP than dextrobetaxolol. The results of the study of the pharmacokinetic behavior of the R and S enantiomers of betaxolol following iv and oral administration of the racemate to healthy male subjects failed to reveal any important difference between the pharmacokinetics of the R and S enantiomer of betaxolol. Thus, the pharmacokinetic behavior of racemic betaxolol accurately reflects the behavior of betaxolol enantiomers in this subject group.

Alprenolol is a beta adrenoreceptor blocking agent and 5HT1A antagonist, developed by AstraZeneca and now available as generic drug. It is used for treatment of hypertension, angina pectoris due to coronary atherosclerosis and acute myocardial infarction.