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Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

Mucinex: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on July 14, 2022.

1. How it works

• Mucinex is a brand (trade) name for guaifenesin.
• Mucinex (guaifenesin) indirectly acts on the gastrointestinal vagal nerves which triggers reflex secretion from submucosal glands and goblet cells, which increases the hydration of the mucus layer which makes it easier for it to be coughed out. Guaifenesin also affects the secretion of mucus from from goblet and Clara cells, which results in reduced mucin production and secretion and reduced viscoelasticity of the mucus. In summary, Mucinex increases the volume and reduces the viscosity (stickiness) of respiratory tract secretions. This makes it easier for mucus trapped in the airways to be coughed out.
• Mucinex belongs to the class of medicines known as expectorants.

2. Upsides

• Aids in the removal of phlegm and mucus from the lungs and airways.
• Thins bronchial secretions.
• May be used to aid in the coughing up of phlegm and mucus in people with a chesty cough.
• Available over the counter.
• May be taken with or without food.
• Mucinex is available as a generic under the name guaifenesin.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Nausea, vomiting, constipation, dizziness, headache, sleepiness or sleeplessness, and rash are more commonly reported; although, in general, Mucinex is well tolerated at dosages used for expectoration.
• Do not use in children aged less than twelve years.
• May not be suitable for people with a persistent cough due to asthma, bronchitis, emphysema, or smoking, or who have a cough that is producing excessive amounts of phlegm. Talk with your doctor first before using Mucinex if you are pregnant or breastfeeding.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Mucinex is an expectorant that helps thin mucus allowing it to be more easily cleared by coughing. Side effects are few; however, anecdotally, sleeplessness may be a problem if Mucinex is taken late in the afternoon.

5. Tips

• Can be administered with or without food. Take with a full glass of water.
• Mucinex is available as an extended-release, bilayer tablet. Do not crush, chew or break this tablet. Swallow whole with a full glass of water. The empty tablet shell may be visible in the stool.
• Drink extra fluids while you are taking Mucinex as these will help loosen the congestion and lubricate your throat.
• Do not give to children under the age of twelve. Do not exceed the maximum recommended dosage of four tablets in 24 hours. If you are using liquid medicine, ensure you measure it with a properly calibrated measure.
• See your doctor if your cough worsens, is accompanied by other symptoms such as a fever, rash, or a persistent headache, or lasts for more than seven days.
• Mucinex will not stop you from coughing but should allow you to more easily clear any sticky secretions in your airways. Do not take with a cough suppressant because the cough reflex is needed to allow you to cough up loosened phlegm or mucus.
• Talk to your pharmacist or doctor before taking any other products for a cough or cold. Several combination products also contain guaifenesin.
• May interact with some other medicines.
• May impair your reaction skills and affect your ability to remain alert. Do not drive until you know how guaifenesin affects you. Conversely, some people report that guaifenesin keeps them awake. Do not take a dose too late in the afternoon if you experience this effect.

6. Response and effectiveness

• Peak plasma concentrations have been reported with immediate-release formulations within 45 minutes.

7. Interactions

Medicines that interact with Mucinex may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with Mucinex. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

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Common medications that may interact with Mucinex include:

• antidepressants, such as amitriptyline or imipramine, or monoamine oxidase inhibitors, such as isocarboxazid, phenelzine, or selegiline
• caffeine
• diet medications such as phentermine
• other cough and cold remedies that may also contain guaifenesin
• some medications used to treat high blood pressure
• stimulants, such as methylphenidate.

Note that this list is not all-inclusive and includes only common medications that may interact with Mucinex. You should refer to the prescribing information for Mucinex for a complete list of interactions.

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Patient resources

A rundown of coronavirus drugs for home

There is no cure for the coronavirus. But there are drugs that can help with symptoms at home and ones that, in a hospital environment, may – or may not – improve the chances of a person who is seriously ill.

The state-of-the-art of COVID-19 pharmacology seems to change by the day.

Medical experts around the world are sharing as much information as quickly as they can as researchers race to find therapies to quell the coronavirus pandemic.

“It’s kind of nuts. In the last four months, there have been more than 2,000 publications for COVID-19-related therapies, descriptions of the disease – it’s just an insane amount of data to keep up with, and unfortunately none of it is of the highest quality,” said Matthew Miller, who has a doctorate in pharmacy and is a clinical specialist in infectious diseases at UCHealth University of Colorado Hospital and the University of Colorado Skaggs School of Pharmacy, both at the Anschutz Medical Campus.

Miller shared with UCHealth Today his state of knowledge as of the afternoon of March 23. He considered drugs for the specific coronavirus, which causes COVID-19, SARS-CoV-2, on two fronts: medications that a person who has contracted the virus can take at home to ease symptoms, and ones that hospital providers are using for those admitted for serious cases.

Try this at home

Roughly 80% of coronavirus cases do not require hospitalization. Information about testing for COVID-19 at UCHealth may be found here. Most cases, identified via a test or not, can be cared for just as well at home, test or not. You treat the symptoms as you would that of a bad flu – adding a major focus on hand hygiene and household disinfection to prevent the coronavirus from spreading to others in the household, Miller says.

• Hydrate with water or other clear fluids (the caffeine in coffee, cola, and many teas is a mild diuretic, diminishing the hydrating effect). “People with high fevers can lose more fluids,” Miller said.
• Pain relievers and fever reducers – including NSAIDs such as ibuprofen – should be fine. A March 11 article in the British medical journal The Lancet raised temporary alarm about the hypothetical possibility of ibuprofen/NSAIDs being a hindrance to COVID-19 treatment. That has since been contradicted by World Health Organization and the Food and Drug Administration. With the exception of patients with conditions that would preclude ibuprofen and other NSAIDs anyway (kidney conditions, high blood pressure, and others), “There’s no specific reason to avoid NSAIDs,” Miller said.
• Lozenges, cough drops, and over-the-counter medicines such as dextromethorphan (Robitussin and others) and guaifenesin (Mucinex and others) can help with the cough that often comes with COVID-19. Dextromethorphan could be the choice for the dry cough that COVID-19 is best known for; guaifenesin that for wetter coughs. Some formulations include both. Again, the idea is to improve symptoms – neither will address the underlying virus.
• Sinus congestion and runny nose isn’t a typical symptom, but over-the-counter decongestants can help here.
• Zinc lozenges may help (or may not) reduce viral replication in the nose and throat, but their effectiveness with SARS-CoV-2 remains unproven.
• Those taking ACE inhibitors or ARBs for cardiovascular issues should continue to do so, Miller says, citing a March 17 American College of Cardiology statement that reads, in part, “The continued highest standard of care for cardiovascular disease patients diagnosed with COVID-19 is top priority, but there are no experimental or clinical data demonstrating beneficial or adverse outcomes among COVID-19 patients using ACE-I or ARB medications.” The statement does add the caveat that the recommendation could change with a better understanding of COVID-19 on these patients.

Miller says that a community pharmacist can help recommend specific products for specific patients. He urges those with symptoms to send a proxy for onsite inquiries, though. People who have any symptoms of illness – such as a fever, cough or shortness of breath, should stay home and isolate themselves so they don’t infect anyone else since COVID-19 is proving to be extremely contagious.