Etafedrine, a sympathomimetic agent that acts on the sympathetic receptors of the bronchial tree relaxing spasm in a manner similar to that of ephedrine, is a bronchodilator and a selective β2-adrenoreceptor agonist. Contraction of the guinea pig tracheal chain by acetylcholine or histamine was antagonized by etafedrine with a higher potency then ephedrine but with a lower potency than epinephrine (adrenaline). Etafedrine did not increase heart rate or force of contraction in guinea pig atria. Unlike ephedrine and tyramine, etafedrine did not induce the release of noradrenaline as was demonstrated in vitro in the perfused rabbit heart and instead acted as a selective β2 adrenoreceptor agonist. Etafedrine also belongs to the family of medications called decongestants. It works by narrowing blood vessels in the nasal passages, helping to relieve nasal stuffiness. Etafedrine has been used in pharmaceutical compositions, such as NETHAPRIN Expectorant, Nethaprin Dospan and Dalmacol, useful in the treatment of asthma and other respiratory disorders including chronic bronchitis.