EMS Expectorant

**EMS Expectorant** is an oral fixed-dose cough and upper-respiratory-symptom syrup containing guaifenesin, doxylamine succinate, and etafedrine hydrochloride. Guaifenesin acts as an expectorant by increasing respiratory-tract fluid and reducing mucus viscosity; doxylamine is a sedating first-generation histamine H1 receptor antagonist that provides antiallergic activity; and etafedrine is a sympathomimetic selective beta-2 adrenergic receptor agonist with bronchodilator activity. The exact three-component product was evaluated in a randomized, placebo-controlled Phase 3 study for acute upper respiratory infections, sponsored by Azidus Brasil; the registry currently reports an unknown study status. ([clinicaltrials.gov](https://clinicaltrials.gov/study/NCT00857987))

Brand names

EMS Expectorant

Other names

guaifenesin + doxylamine succinate + etafedrine hydrochloride