Entex

**Semantic type:** Pharmacologic Substance

**Definition:** A commercial combination preparation containing guaifenesin and phenylephrine hydrochloride with expectorant and decongestant activities. Guaifenesin works by drawing water into respiratory tracts, thereby reducing adhesiveness and surface tension of mucus as well as increasing hydration of mucus. This reduces the viscosity of mucus and makes the cough more productive. Phenylephrine hydrochloride, a direct-acting sympathicomimetic amine, activates alpha-adrenergic receptors in the nasal mucosa thereby causing vasoconstriction, reduces swelling of nasal mucous membranes and decreases nasal and sinus congestion.