Guaifenesin

Guaifenesin is an expectorant that is primarily used to relieve chest congestion by aiding in the removal of mucus. The USFDA approved this drug in 1952, and a new application for the extended-release version was approved on July 12, 2002. It makes mucus less sticky and thus easier to remove from the airways. It is the most widely available cough drug. It is also used to treat infections or allergies, bronchitis, and other respiratory problems, wet cough, and productive cough.

BRAND NAMES:

Mucinex - These are extended-release bilayer tablets in which Guaifenesin acts as the main active ingredient available in strengths of 600mg and 1200mg.

Mucinex DM – Mucinex DM are combination of guaifenesin and dextromethorphan which are available as Mucinex DM 1200mg of guaifenesin and 60mg of dextromethorphan HBr extended release bilayered tablets and Mucinex DM 600mg of guaifenesin and 30mg of dextromethorphan HBr extended release bilayered tablets.

Mucinex D – In this guaifenesin and pseudoephedrine are the main active ingredients present in the drug in treating the runny nose. These are available in the markets with combinational strengths are 1200mg of guaifenesin and 120mg of pseudoephedrine extended-release bilayered tablets.

Broncotron - It is an oral liquid that is available in the combination of two active ingredients known as guaifenesin and dextromethorphan.

Cheratussin – Cheraussin AC 10mg – 100mg/Ml oral liquid available in the combination of Codeine and guaifenesin.

Alkof SF – It is a oral solution with combination of Guaifenesin 50mg, bromhexine 4mg and diphenhydramine 8mg.

MECHANISM OF ACTION:

Guaifenesin acts as an expectorant, increasing the volume and lowering the thickness of bronchial secretions, promoting the flow of respiratory tract secretions. It may improve the efficacy of the cough reflex and help the evacuation of secretions. In some situations, it can serve as an NMDA receptor antagonist to produce anticonvulsant and muscle relaxant actions to some extent.

PHARMACOKINETICS:

Absorption: It is well absorbed from and along the gastrointestinal tract after oral administration.

Distribution: The apparent volume of distribution of guaifenesin is 116L. Protein binding of guaifenesin is not readily available.

Metabolism: The medicine is metabolized promptly in the liver through oxidation to β-(2-methoxyphenoxy)-lactic acid. The primary enzyme for guaifenesin metabolism is O-demethylase. The primary metabolites of the substance are β-(2-methoxyphenyl)-lactic acid and demethylated hydroxyl guaifenesin, both inactive.

Excretion: After metabolisis of the drug it is excreted through urine.

PHARMACODYNAMICS:

Guaifenesin causes an increase in the flow or viscosity of gastric secretions, which protests the culinary activity and eventually transforms dry cough into a productive and less frequent cough. Reduced viscosity and adhesiveness of such secretions improve mucociliary activity in clearing collected secretions from the airway.

DOSAGE AND ADMINISTRATION:

Guaifenesin is available in orally administered tablets, extended-release tablets, syrups, capsules, and granules. Tablets are available in strengths 15 to 400mg and 20 to 400mg. Extended-release tablets are available in 30 to 600mg and 60 to 1200mg. Syrups are available in many strengths. The tablets, dissolving granules, syrup, and capsules can be taken with or without food every four hours. The extended-release tablets are usually taken with or without food or every 12 hours.

The granule version of this medication is given in 2 to 4 packets every 4 months, with a maximum of 6 doses every 24 hours.

Tablets are dosed at 1 to 2 tablets every 12 hours, with a daily maximum of 4 pills. The maximal strength of the pill is given as a single tablet every 12 hours and a maximum of two tablets per 24 hours.

Syrups mostly consist of formulations of dextromethorphan and guaifenesin which should not exceed 60ml daily.

CONTRAINDICATIONS:

The combination of dextromethorphan and guaifenesin drug includes concominant monoamine oxidase inhibitor administration(MOAI) it is contraindicated in patients with phenylketonuria, severe liver or kidney disease, kidney stones, and patients younger than 4 years old with known hypersensitivity reactions to dextromethorphan or guaifenesin.

DRUG INTERACTIONS:

It interacts with the drug including cimetidine, naltrexone, and samidorphan. It is need to discuss with the physician if the patient is already treated with other medications like antihistamines, opioid pain and cough relievers, muscle relaxants, and anxiety medications.

FOOD INTERACTIONS:

Guaifenesin can be taken with or without food as it does not affect the absorption. It should be taken with a full glass of water.

ADVERSE EFFECTS: