Sympathomimetics are a class of drugs whose properties mimic those of a stimulated sympathetic nervous system. As such they increase cardiac output, dilate bronchioles, and usually produce constriction of blood vessels. Sympathomimetics include the naturally occurring substances adrenaline (epinephrine), noradrenaline (norepinephrine), and other catecholamines such as dopamine, as well as the synthetic drugs pseudoephedrine, phenylephrine, and phenylpropanolamine. In medicine, they are commonly prescribed in cardiac emergencies including shock and anaphylaxis, in some cases for weight loss, and in cold remedies, where they shrink swollen membranes in the upper respiratory tract. In recent years, phenylpropanolamine has been removed from over-the-counter cold formulations after it was implicated in causing an increased risk of hemorrhagic stroke. Epinephrine (INN) or adrenaline (BAN) is a hormone and a neurotransmitter. ... Norepinephrine, known as noradrenaline outside the USA, is a catecholamine and a phenethylamine with chemical formula C8H11NO3. ... Dopamine is a chemical naturally produced in the body. ... Pseudoephedrine is a sympathomimetic amine commonly used as a decongestant. ... Phenylephrine hydrochloride is an α-agonist used medically to increase blood pressure, as a nasal decongestant and also to dialate the pupil. ... Phenylpropanolamine (PPA) is a drug of the phenethylamine family used in bronchial and nasal decongestants, and also as an appetite suppressant. ... In medicine, shock is a life-threatening medical emergency characterized by inability of the body to supply enough oxygen to meet tissue requirements. ... Anaphylaxis is a severe and rapid systemic allergic reaction to a trigger substance, called an allergen. ... A stroke or cerebrovascular accident (CVA) occurs when the blood supply to a part of the brain is suddenly interrupted by occlusion (an ischemic stroke- approximately 90%of strokes) or by hemorrhage (a hemorrhagic stroke - approximately 10% of strokes). ...