Fenoterol: An adrenergic beta-2 agonist that is used as a bronchodilator and tocolytic.Adrenergic beta-Agonists: Drugs that selectively bind to and activate beta-adrenergic receptors.Atropine Derivatives: Analogs and derivatives of atropine.Chlorofluorocarbons, Methane: A group of methane-based halogenated hydrocarbons containing one or more fluorine and chlorine atoms.Ipratropium: A muscarinic antagonist structurally related to ATROPINE but often considered safer and more effective for inhalation use. It is used for various bronchial disorders, in rhinitis, and as an antiarrhythmic.Butoxamine: A beta-2 selective adrenergic antagonist. It is used primarily in animal and tissue experiments to characterize BETA-2 ANDRENERGIC RECEPTORS.Aerosol Propellants: Compressed gases or vapors in a container which, upon release of pressure and expansion through a valve, carry another substance from the container. They are used for cosmetics, household cleaners, and so on. Examples are BUTANES; CARBON DIOXIDE; FLUOROCARBONS; NITROGEN; and PROPANE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Adrenergic beta-2 Receptor Agonists: Compounds bind to and activate ADRENERGIC BETA-2 RECEPTORS.Bupranolol: An adrenergic-beta-2 antagonist that has been used for cardiac arrhythmia, angina pectoris, hypertension, glaucoma, and as an antithrombotic.Procaterol: A long-acting beta-2-adrenergic receptor agonist.Albuterol: A short-acting beta-2 adrenergic agonist that is primarily used as a bronchodilator agent to treat ASTHMA. Albuterol is prepared as a racemic mixture of R(-) and S(+) stereoisomers. The stereospecific preparation of R(-) isomer of albuterol is referred to as levalbuterol.Receptors, Adrenergic, beta-2: A subclass of beta-adrenergic receptors (RECEPTORS, ADRENERGIC, BETA). The adrenergic beta-2 receptors are more sensitive to EPINEPHRINE than to NOREPINEPHRINE and have a high affinity for the agonist TERBUTALINE. They are widespread, with clinically important roles in SKELETAL MUSCLE; LIVER; and vascular, bronchial, gastrointestinal, and genitourinary SMOOTH MUSCLE.Ethanolamines: AMINO ALCOHOLS containing the ETHANOLAMINE; (-NH2CH2CHOH) group and its derivatives.Aerosols: Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents.Nebulizers and Vaporizers: Devices that cause a liquid or solid to be converted into an aerosol (spray) or a vapor. It is used in drug administration by inhalation, humidification of ambient air, and in certain analytical instruments.Bronchodilator Agents: Agents that cause an increase in the expansion of a bronchus or bronchial tubes.Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.