Mucinex DM dosage, forms, and strengths

Mucinex DM is an over-the-counter (OTC) combination medication that relieves cough and chest congestion caused by the common cold, flu, and allergies. Each tablet combines dextromethorphan hydrobromide, a cough suppressant, with guaifenesin, a drug that loosens mucus and bronchial secretions in the lungs. Guaifenesin has a short duration, so each Mucinex “bi-layer” tablet contains both immediate-release and extended-release versions of guaifenesin for long-term effectiveness. Mucinex DM is taken by mouth once every 12 hours and is available in regular and maximum strength.

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Mucinex DM dosage, forms, and strengths

Mucinex DM is taken as immediate- and extended-release bilayer tablets.

• Mucinex DM tablets: 600 milligrams (mg) guaifenesin, 30 mg dextromethorphan hbr

• Maximum Strength Mucinex DM tablets: 1200 mg guaifenesin, 60 mg dextromethorphan

Mucinex DM dosage for adults

The standard recommended dose of Mucinex DM is one to two regular-strength tablets (600/30 mg) or one Maximum Strength tablet (1200/60 mg) taken by mouth every 12 hours.

• Standard Mucinex DM dosage for adults: 600/30–1200/60 mg (one to two regular-strength tablets or one maximum strength tablet) every 12 hours

• Maximum Mucinex DM dosage for adults: 1200/60 mg (two regular-strength tablets or one maximum strength tablet) every 12 hours 

Mucinex DM dosage for children

Mucinex DM is approved for use in adults and children 12 years of age and older. It is not to be given to children younger than 12. 

• Standard Mucinex DM dosage for children ages 12 and above: 600/30–1200/60 mg (one to two regular-strength tablets or one maximum strength tablet) every 12 hours

• Maximum Mucinex DM dosage for children ages 12 and above: 1200/60 mg (two regular-strength tablets or one maximum strength tablet) every 12 hours

Mucinex DM is not available in children’s formulations. However, both guaifenesin and dextromethorphan, the active ingredients in Mucinex DM, are approved to be given to children as young as 4 years of age. Instead of Mucinex DM, Mucinex offers two pediatric products formulated for children as young as 4 that combine both guaifenesin and dextromethorphan: Mucinex Children’s Cough, available as a flavored liquid or flavored granules, and Mucinex Children’s FreeForm Mucus and Cough, sold as a flavored liquid. Neither of these products contains extended-release guaifenesin, so doses are given every four hours.

Mucinex DM dosage for wet and dry cough

Mucinex DM is indicated to relieve productive (wet) and unproductive (dry) coughing caused by the common cold, flu, or allergies. The expectorant (guaifenesin) helps to loosen and thin mucus in the lung’s passageways, making coughs more productive. The cough suppressant (dextromethorphan) relieves the intensity and frequency of coughs.

• Standard Mucinex DM dosage for wet or dry cough: 600/30–1200/60 mg (one to two regular-strength tablets or one maximum strength tablet) every 12 hours

• Maximum Mucinex DM dosage for wet or dry cough: 1200/60 mg (two regular-strength tablets or one maximum strength tablet) every 12 hours

Mucinex DM dosage for pets

Human OTC medicines like Mucinex DM should not be given to animals without consulting a veterinarian first. The doses may be too high and there are inactive ingredients in human medicines that may be harmful to animals. 

The active ingredients in Mucinex DM, guaifenesin, and dextromethorphan, are used in animals. For dextromethorphan, the standard dose is 0.5–2 mg of dextromethorphan per kilogram of body weight every six to eight hours in both cats and dogs. That translates to 0.23 to 0.9 mg per pound of body weight. For guaifenesin, the standard dose for both cats and dogs is 3–5 mg per kg of body weight (1.35–2.25 mg per pound) every eight hours.

There is at least one OTC veterinary cough medicine containing both guaifenesin and dextromethorphan similar to Mucinex DM. The manufacturer’s recommended dosing is one-half tablet (50 mg/5 mg) every four hours for small dogs and cats and one tablet (100 mg/10 mg) every four hours for large dogs. Although this product is available without a prescription, a veterinarian should be consulted first. A cough in an animal may be a symptom of a more serious condition that needs veterinary care rather than symptom relief.

How to take Mucinex DM

Mucinex DM is taken as a tablet by mouth. It can be taken with or without food.

• Take the tablet with a full glass of water.

• Do not crush, chew, or break the tablet.

The following tips can help ensure the safe and effective use of Mucinex DM:

• Follow the instructions on the medicine label. Do not take more than directed.

• Store

  at room temperature (68 to 77 degrees

  Fahrenheit).

• Always check the expiration date on the Mucinex DM packaging. If the medicine has passed its expiration date, dispose of it safely and purchase a new package.

• Do not use Mucinex DM if you are

  such as Marplan (isocarboxazid) or Nardil (phenelzine). Combining dextromethorphan with an MAO inhibitor can be hazardous and even fatal. If uncertain about whether a drug is an MAO inhibitor or not, talk to a doctor, pharmacist, or other healthcare professional to help identify prescription drugs.

• Mucinex DM helps

  loosen phlegm and thin mucus in the lungs. Drinking extra fluids and keeping the air moist with a humidifier or steam vaporizer will also help loosen mucus in the lung’s passageways.

• The manufacturer, Reckitt Benckiser, advises that any woman who is pregnant or breastfeeding consult with a healthcare professional before taking Mucinex DM.

• A cough may be a symptom of a more serious illness. If a cough is chronic, recurrent, lasts more than seven days, has too much phlegm, or is accompanied by other symptoms such as fever or headache, seek professional medical advice. 

Mucinex DM dosage FAQs

How long does it take Mucinex DM to work?

Mucinex DM combines both immediate-release and extended-release active ingredients, so the effects should begin relatively quickly and last up to 12 hours. Both active ingredients, guaifenesin and dextromethorphan, will begin to show effects in 15-30 minutes. Both are quickly absorbed by the digestive system and begin to work as soon as they hit the bloodstream. 

How long does Mucinex DM stay in your system?

Mucinex DM consists of an outer tablet that contains immediate-release versions of its two active ingredients guaifenesin and dextromethorphan. The inner tablet slowly releases guaifenesin over the next 12 hours. Cough relief should last about 12 hours.

Guaifenesin, the expectorant in Mucinex DM, is rapidly cleared from the body, having a half-life of only one hour. A drug’s half-life is the amount of time it takes for the body to eliminate half of the drug. However, the extended-release format in Mucinex DM allows the drug to be continually released into the body over a longer period, so the effects last about 12 hours. 

However, dextromethorphan is different. With a half-life of three hours for many people to more than a day for 1 out of 10 people, dextromethorphan can be active anywhere from 11 hours to longer than a day. To make things more complex, dextromethorphan is converted by the body into dextrorphan, a very similar drug that also stops coughing. Dextrorphan has its own half-life. Once you crunch the math on all of this, both dextromethorphan and dextrorphan are usually eliminated within two days after taking the last dose of Mucinex DM.

What happens if I miss a dose of Mucinex DM?

Mucinex DM is taken to relieve symptoms, so a missed dose is not a problem. Just take the missed dose when made aware of it. Remember, though, that taking a missed dose will reset the dosage clock. Do not take another dose until at least 12 hours after the missed dose was taken. Never take extra medicine to make up for a missed dose.

How do I stop taking Mucinex DM?

If used as directed, Mucinex DM can be discontinued without causing any problems. Dextromethorphan, the cough medicine in Mucinex DM, is commonly abused and can cause psychological dependency. When taken chronically in large doses, dextromethorphan may cause physical and psychological withdrawal symptoms.

Mucinex DM is not intended for continuous or chronic use. People with a chronic cough due to asthma, smoking, emphysema, or chronic bronchitis should talk to a doctor or other healthcare professional before taking Mucinex DM. For others, if a symptomatic cough persists for longer than seven days, stop taking Mucinex DM and seek medical advice. Mucinex DM should also be discontinued if:

• The cough comes back.

• The cough is accompanied by other symptoms such as fever, headache, or rash.

• There is any sign of an allergic reaction such as swelling, hives, or trouble breathing.

What is the maximum dosage for Mucinex DM?

The maximum dosage of Mucinex DM is 1200 mg/60 mg every 12 hours to a maximum of 2400 mg/120 mg in a single day. The maximum 12-hour dosage amounts to two regular Mucinex DM tablets or one Maximum Strength Mucinex DM tablet.

What interacts with Mucinex DM?

Mucinex DM can be taken with or without food. The absorption of the cough medicine, dextromethorphan, is unaffected by food, though taking guaifenesin on a full stomach may slow its absorption into the body.

Guaifenesin, the expectorant in Mucinex DM, has no known significant drug interactions.

Dextromethorphan, though, is different. It has several significant drug interactions. Some may be hazardous or even fatal. It is a good idea to check with a doctor, pharmacist, or other healthcare professional about possible drug interactions before taking any medication containing dextromethorphan, even if it’s “safe” enough to be purchased without a prescription.

Above all, dextromethorphan should never be taken with monoamine oxidase inhibitors (MAO inhibitors or MAOIs). The FDA advises that any MAOI be discontinued for at least 14 days before taking dextromethorphan. The combination can cause mild to fatal serotonin syndrome, a medical condition that results in an excess of serotonin, a chemical that transmits nerve signals.

Mild to severe cases of serotonin syndrome might also be caused by combining dextromethorphan with a number of other types of drugs. These include antidepressants, opioid painkillers, amphetamines, anti-nausea drugs, migraine medications, ADHD medications, Parkinson’s medications, and some herbal supplements such as St. John’s wort, ginseng, and tryptophan. Again, if unsure, consult with a doctor, pharmacist, or other healthcare provider before taking dextromethorphan.

Resources:

• Mucinex DM

• Mucinex DM drug facts

• Mucinex website

• Dextromethorphan

• Guaifenesin

• Guaifenesin drug summary

• Interactions between nonprescription products and psychotropic medications

• Poisoning & Drug Overdose Chapter 60: Dextromethorphan

• Serotonin syndrome: Risk with concurrent use of SSRIs and other serotonergic meds