Astralean (Clenbuterol) from Alpha Pharma is indicated for the treatment of bronchitis in the treatment of airway obstruction, such as chronic obstructive pulmonary disease (COPD). Astralean is a widely used bronchodilator in many parts of the world. The drug is most commonly made in 20mcg tablets, but it is also prepared in syrup and injectable form. Astralean belongs to a broad group of drugs called sympathomimetics. These drugs affect the sympathetic nervous system in a variety of ways, largely mediated by the distribution of adrenoceptors. There are actually nine different types of these receptors in the body that are classified as either alpha or beta and are further categorized by type number. Depending on the specific affinities of these agents for the various receptors, they can potentially be used in the treatment of conditions such as asthma, hypertension, cardiovascular shock, arrhythmia, migraine headache and anaphylactic shock. The text Goodman and Gillman's The Pharmacological Basis of Therapeutics Edition does a good job of describing the diverse nature in which these drugs affect the body.

Most of the actions of catecholamines and sympathomimetics can be divided into seven broad types; Peripheral arousal effects on certain types of smooth muscle, such as those in blood vessels supplying the skin, kidney and mucous membranes, and on glandular cells, such as those of the salivary glands and sweat glands; A peripheral inhibitory effect on certain other types of smooth muscle, such as those in the wall of the intestine, in the bronchial tree, and in the blood vessels that supply skeletal muscle; A cardiac excitation effect that is responsible for an increase in heart rate and force of contraction; Metabolic effects such as an increase in the rate of glycogenolysis in the liver and muscle and the release of free fatty acids from adipose tissue; Endocrine effects such as modulating the secretion of insulin, rennin and pituitary hormones; CNS actions, such as breath stimulation and, with some of the drugs, an increase in wakefulness and psychomotor activity, and a decrease in appetite; And presynaptic effects which either inhibit or facilitate the release of neurotransmitters such as B. nor-epinephrine and acetylcholine result.

The drug Astralean is specifically a selective beta-2 sympathomimetic that primarily affects only one of the three subgroups of beta receptors. Of particular interest is the fact that this drug has little beta-1 stimulatory activity. Because beta-1 receptors are closely related to the cardiac effects of these agents, Astralean can reduce reversible airway obstruction (and the effects of beta-2 stimulation) with much fewer cardiovascular side effects compared to non-selective beta agonists. Clinical studies with this drug show it is extremely effective as a bronchodilator, with a low level of user discomfort and high patient compliance. Astralean also shows an extremely long half-life in the body which is measured to be around 34 hours. This makes steady blood counts easy to achieve using just the once or twice daily dosing schedule at most. This of course makes it much easier for the patient to use, and may bind in its high compliance rate. Although Astralean is available in many other countries, this compound has never been approved for use in the United States. The fact that there are a number of similar, effective asthma drugs already in this country may have something to do with it, as a potential drug company would likely not find it a profitable product enough to benefit from FDA approval. Regardless, foreign astralic preparations are widely available on the US black market.