guaifenesin, phenylephrine, Entex

GENERIC NAME: guaifenesin, and phenylephrine


DRUG CLASS AND MECHANISM: Entex is a medication that contains 2 different drugs, an expectorant (guaifenesin) and a decongestant (phenylephrine). The expectorant effects of guaifenesin promote drainage of mucus from the lungs by thinning the mucus. It also lubricates the irritated respiratory tract. Phenylephrine relieves stuffy nose by constricting blood vessels in the nasal air passages. This reduces the flow of fluid out of the blood vessels and into the tissues of the air passages.

NOTE: Entex LA is a combination of guaifenesin and phenylephrine in a longer acting capsule. Entex-PSE is a combination of guaifenesin and another decongestant, pseudoephedrine.



PREPARATIONS: Capsules; liquid

STORAGE: Tablets and liquid should be stored below 30°C (86°F). Do not refrigerate the liquid.

PRESCRIBED FOR: Entex and Entex PSE are used for the temporary relief of runny nose, sneezing, nasal congestion from the common cold, bronchitis, or pharyngitis. Entex and Entex PSE also are used for inflamed nasal passages (sinusitis) and sinus congestion.

DOSING: Entex and Entex PSE may be taken with or without food. They must be used cautiously in patients with heart (coronary artery) disease and angina, and diabetes.

DRUG INTERACTIONS: Entex and Entex PSE should not be taken with MAO inhibitors drugs.

PREGNANCY: Phenylephrine and pseudoephedrine cause birth defects in some animal species. Additionally, there have been associations between first trimester exposure to these medications and malformations, primarily minor malformations. Although one analysis found a correlation between guaifenesin use in the first trimester of pregnancy and an increased risk of hernia, others found no increased risk of malformations. Thus, Entex and Entex PSE should be used in pregnancy only if the physician feels that the potential benefits outweigh the potential risks.

NURSING MOTHERS: There is no information on the secretion of phenylephrine or guaifenesin into breast milk. Pseudoephedrine is secreted in breast milk. The American Academy of Pediatrics considers pseudoephedrine to be compatible with nursing.

SIDE EFFECTS: Side effects of Entex and Entex PSE include stimulation of the nervous system leading to nervousness, restlessness, excitability, dizziness, headache, fear, anxiety, tremor, and even hallucinations and convulsions (seizures).

Reference: FDA Prescribing Information

Last Editorial Review: 11/14/2002

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