Dyphylline is 7-(2,3-dihydroxypropyl)-theophylline, a white, extremely bitter, amorphous powder that is freely soluble in water and soluble in alcohol. Dyphylline is stable in gastrointestinal fluids over a wide range of pH. Dyphylline is a xanthine derivative with pharmacologic actions similar to theophylline and other members of this class of drugs. Its primary action is that of bronchodilation, but it also exhibits peripheral vasodilatory and other smooth muscle relaxant activity to a lesser degree. The bronchodilatory action of dyphylline, as with other xanthines, is thought to be mediated through competitive inhibition of phosphodiesterase with a resulting increase in cyclic AMP producing relaxation of the bronchial smooth muscle. Dyphylline exerts its bronchodilatory effects directly and, unlike theophylline, is excreted unchanged by the kidneys without being metabolized by the liver. Because of this, dyphylline pharmacokinetics and plasma levels are not influenced by various factors that affect liver function and hepatic enzyme activity, such as smoking, age, congestive heart failure, or concomitant use of drugs which affect liver function.

Methoxyphenamine also known as 2-methoxy-N-methylamphetamine (OMMA), is a beta adrenergic receptor agonist nd is used as a bronchodilator to treat asthma, chronic obstructive pulmonary disease (COPD) and postinfectious cough. In addition, methoxyphenamine using is prohibited in sports according to the regulations of the World Anti-Doping Agency (WADA).

Theobromine is the primary alkaloid present in the cocoa and chocolate. Theobromine is found in the shells and beans of the cacao plant and it is extracted from the husks of the bean and used for the synthesis of caffeine. Theobromine is an adenosine A1 and A2a receptor antagonist. Thesodate is used as a vasodilator, a diuretic, and heart stimulant. And similar to caffeine, it may be useful in management of fatigue and orthostatic hypotension. The symptomatic adverse reactions produced by theobromine are more or less tolerable and if they become severe, they can be treated symptomatically, these include anxiety, restlessness, tremors, sleeplessness, nausea and vomiting, loss of appetite. Theobromine is currently not in use as a medicinal drug.

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.

Bambuterol is an active precursor of the selective beta2-adrenergic agonist terbutaline. Bambuterol is the bis-N,N-dimethyl-carbamate of terbutaline. Bambuterol is a remarkably selective and potent inhibitor of cholinesterase. BAMBEC (Bambuterol hydrochloride) oral solution or tablets are indicated for the management of asthma, bronchospasm and/or reversible airways obstruction.

Procaterol is a beta2-adrenoreceptor agonist. It is a bronchodilator that may be administered orally or by aerosol inhalation for the treatment of dyspnea caused by bronchial asthma, chronic bronchitis, and pulmonary emphysema. The drug is not approved in the USA, but is available in Japan, Indonesia, and other countries worldwide.

Hexoprenaline is a selective beta2-adrenoreceptor agonist indicated for use in the treatment of bronchospasm associated with obstructive airways diseases, including asthma, bronchitis and emphysema. In many countries the drug is used as tocolytic agent (under the trade name gynipral).

Doxofylline (7-(1, 3-dioxalan-2-ylmethyl) theophylline) is a novel xanthine bronchodilator which differs from theophylline in that it contains a dioxalane group in position 7. Doxofylline is indicated for the treatment of bronchial asthma, pulmonary disease with spastic bronchial component and Chronic Obstructive Pulmonary Disease (COPD). Doxofylline does not directly inhibit any of the known HDAC enzymes, and did not inhibit any phosphodiesterase (PDE) enzyme sub types or act as an antagonist at any of the known adenosine receptors, except for PDE2A(1), and adenosine A(2A) and only at the highest tested concentration (10(-4) M). Doxofylline has greatly decreased affinity towards adenosine A1 and A2 receptors, which explain its better safety profile. Moreover, it does not interfere with calcium influx into the cells nor antagonize calcium channel blockers. Doxofylline has been shown to be a more potent bronchodilator with fewer side effects than theophylline. This drug should not be administered together with other xanthine derivatives, including beverages and foods containing caffeine.

Reproterol is a short-acting β2 adrenoreceptor agonist used in the treatment of asthma. Reproterol increases the generation of cAMP in isolated peripheral blood monocytes in vitro more effectively than does orciprenaline. In the presence of the highly potent but nonselective ß-antagonist, propranolol, the cAMP-generating action of reproterol was inhibited only partially. Reproterol has gained wide use when it was licensed as a fixed combination therapy with cromoglycate. Until today, the bronchodilator effects of reproterol and the bronchoprotective and anti-inflammatory actions of cromoglycate combined in one inhaler remain the successful fixed combination of a disease-modifying and symptomatic drug for the treatment of asthma.

Etamiphylline is the respiratory stimulant. No information is available about pharmacodynamics of etamiphylline. No human pharmacokinetic data are available. Etamiphylline seems to be a rather weaker bronchodilator than theophylline when administered orally.