Mucinex D (guaifenesin and pseudoephedrine) and Mucinex DM (guaifenesin and dextromethorphan) are cough and cold products that contain two active ingredients each.
Both products have the active ingredient guaifenesin, which loosens phlegm and makes it easier to cough out.
They differ because Mucinex D also contains pseudoephedrine, a nasal decongestant, while Mucinex DM contains dextromethorphan, a cough suppressant.
Also, Mucinex DM is available over-the-counter (OTC), while Mucinex D is sold behind the counter, requires ID, and can only be purchased in limited quantities without a prescription.
This article discusses the similarities and differences between Mucinex D and Mucinex DM.
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Mucinex D vs Mucinex DM: What Are They and How Do They Work?
Mucinex D contains guaifenesin, an expectorant, and pseudoephedrine, a nasal decongestant.
The guaifenesin helps loosen phlegm and thin secretions in the lungs to clear thebronchial passageways of mucus and make coughs more productive.
The pseudoephedrine works by causing vasoconstriction to temporarily relieves nasal congestion, restore free breathing through the nose, promote nasal and/or sinus drainage, and relieve sinus congestion and pressure. A product containing a D after the name, such as Mucinex D, usually has a decongestant (e.g., phenylephrine or pseudoephedrine).
Mucinex DM also contains guaifenesin, an expectorant, and dextromethorphan, a cough suppressant, in each tablet.
The guaifenesin helps loosen phlegm and thins bronchial secretions to clear mucus and make coughs more productive, while the dextromethorphan suppresses the intensity of coughing and reduces the impulse to cough.
Dosage Strengths and Forms
Mucinex D is available as an oral extended-release (ER) tablet. Depending on the dosage strength, it is recommended to take either one (1,200 milligrams/120 milligrams tablet) or two (600 milligrams/60-milligram tablet) every 12 hours. Because of its design, tablets must not be cut, crushed, or chewed.
Mucinex DM is available as an oral ER tablet. Depending on the dosage strength, it is recommended to take one (1,200 milligrams/60 mg tablet) or two (600 mg/30 mg tablet) every 12 hours. Like Mucinex D, these tablets must not be cut, crushed, or chewed.
Mucinex DM is also available as an oral solution. It is marketed under Mucinex Fast-Max DM in cherry and honeyberry flavors. Each 20 milliliter contains 400 milligrams of guaifenesin and 20 milligrams of dextromethorphan.
| Name | Dosage Form | Dose Strengths | Recommended Dosages |
| Mucinex D | ER tablet | 600 mg (guaifenesin)/60 mg (pseuoephedrine); 1,200 mg/120 mg | 2 tablets every 12 hours; 1 tablet every 12 hours |
| Mucinex DM | ER tablet | 600 mg (guafenesin)/30 mg (dextromethorphan); 1,200 mg/60 mg | 2 tablets every 12 hours; 1 tablet every 12 hours |
| Mucinex Fast-Max DM | Solution | 400 mg (guafenesin)/20 mg (dextromethorphan) | 20 mL every 4 hours, as needed |
Mucinex D vs. Mucinex DM: Side Effects
Mucinex D and Mucinex DM are generally well tolerated at recommended doses. Side effects can occur, although you may not have any.
Common side effects that may be experienced with both Mucinex D and Mucinex DM include:
- Dizziness
- Drowsiness
- Nausea or vomiting
- Headache
- Rash
When taken at higher doses, Mucinex D and Mucinex DM can also cause kidney stones.
Mucinex D
Other side effects that may be experienced with Mucinex D include:
- Anxiety
- High blood pressure
- Insomnia
- Heart palpitations
- Tremor
- Urinary retention
Serious side effects that may be experienced with Mucinex D include:
- Irregular heartbeat
- Hypertension
- Severe skin reaction
Mucinex DM
Other side effects that may be experienced with Mucinex DM include:
- Constipation
- Stomach pain
- Fatigue
Serious side effects that may be experienced with Mucinex DM include:
- Abuse/dependence
- Serotonin syndrome
Drug-Drug Interactions
Mucinex D and Mucinex DM should not be taken within 14 days of taking medications called monoamine oxidase inhibitors (MAOIs), such as:
- Isocarboxazid
- Tranylcypromine
- Phenelzine
- Selegiline
When used with pseudoephedrine, MAOIs can increase the risk of severely high blood pressure. MAOIs can also interact with the dextromethorphan in Mucinex DM, potentially leading to serotonin syndrome.
Safety Warnings
While generally safe, these medications may not be appropriate in some situations.
Mucinex D contains a decongestant, so be cautious about using it and discuss it with your healthcare provider if you:
- Have heart disease
- Have uncontrolled high blood pressure
- Have diabetes
- Have hyperthyroidism
- Have bowel obstruction
- Have glaucoma
- Have benign prostate hyperplasia (enlarged prostate)
- Are older than 65 years
Mucinex DM might not be appropriate for these populations.
Due to limited research, the safety of these products when used during pregnancy has not been established. Healthcare providers may recommend avoiding taking guaifenesin in the first trimester of pregnancy unless the benefits outweigh the potential risks.
Stop taking the medication and contact your healthcare provider if your symptoms do not improve within seven days, recur, or occur with a fever, rash, or persistent headache.
Misuse Warning
Mucinex D
Pseudoephedrine, an active ingredient found in Mucinex D, can be used illegally to produce methamphetamine, also known as “meth,” a powerful, highly addictive stimulant. The use and abuse of methamphetamine can cause harmful effects such as irritability, nervousness, insomnia, nausea, depression, and brain damage.
Mucinex DM
Mucinex DM contains dextromethorphan, which can be abused in high doses to experience euphoria and visual and auditory hallucinations. Some of the many psychoactive effects associated are confusion, inappropriate laughter, agitation, paranoia, euphoria, hallucinations, and other sensory changes, including the feeling of floating and changes in hearing and touch.
Long-term abuse is associated with severe addiction. The use of high doses in combination with alcohol or other drugs is particularly dangerous, with deaths reported.
Which One Is Right for You?
If you are experiencing a cough, deciding between Mucinex D and Mucinex DM may be a tough choice. Since these products contain guaifenesin, they help reduce chest congestion to move phlegm upwards and out.
Mucinex D is appropriate for productive coughs with sinus congestion or a stuffy nose. The guaifenesin helps loosen phlegm and make coughs more productive, while the pseudoephedrine relieves nasal congestion, promotes nasal and/or sinus drainage, and relieves sinus congestion and pressure.
Mucinex D contains a decongestant, so it should be used cautiously in those with heart disease or uncontrolled hypertension (high blood pressure), diabetes, hyperthyroidism, bowel obstruction, glaucoma, benign prostatic hyperplasia (BPH), and those 65 and older. Mucinex DM may be a more appropriate option in these populations.
Mucinex DM is more suitable for dry, unproductive cough or to suppress productive cough at night to allow for restful sleep, since the cough-suppressing effects persist for five to six hours after ingestion.
Sudafed vs. Mucinex: What’s the Difference?
Summary
Mucinex D and Mucinex DM are cough and cold products containing guaifenesin to loosen phlegm.
Although both Mucinex D and Mucinex DM are practical options for cough relief, deciding which one is best for you might depend on your cough type and other factors, including coexisting health conditions.
Mucinex D has pseudoephedrine and relieves productive coughs with congestion, while Mucinex DM contains dextromethorphan and helps relieve dry or unproductive coughs. Dextromethorphan–a cough suppressant–can cause hallucinations and euphoria at high doses, which increases the risk of abuse and dependence.
Because it contains pseudoephedrine–which can be used to produce meth–Mucinex D requires an ID to purchase, whereas Mucinex MD is available OTC.
Frequently Asked Questions
Is there a generic version of Mucinex D and Mucinex DM?
Yes, generic versions of both medications exist. The generic version of Mucinex D is pseudoephedrine/guaifenesin, and the generic version of Mucinex DM is dextromethorphan/guaifenesin.
Should I take Mucinex D or DM at night?
Mucinex DM contains two medications: An expectorant and a cough suppressant. Mucinex DM can be taken either in the daytime or at nighttime. It will help reduce chest congestion and suppress cough at night, allowing for restful sleep.
Mucinex D contains an expectorant and a decongestant. The decongestant component can cause sleep disturbances/insomnia and is therefore not advised to be used at night.
What does the ‘DM’ stand for in Mucinex DM?
A product with DM at the end, such as Mucinex DM orRobitussin DM, contains dextromethorphan. Those with a D after the name, such as Mucinex D, usually contain a decongestant, such as phenylephrine or pseudoephedrine.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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MedlinePlus. Dextromethorphan.
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By Temitope Oyeleke, PharmD
Oyeleke is a Maryland-based clinical pharmacist. She received her Doctor of Pharmacy degree from Hampton University School of Pharmacy.
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