What is Mucinex DM (Dextromethorphan Guaifenesin)?

Dextromethorphan is a cough suppressant. It affects the signals in the brain that trigger cough reflex.
Guaifenesin is an expectorant. It helps loosen congestion in your chest and throat, making it easier to cough out through your mouth.
The combination of dextromethorphan and guaifenesin is used to treat cough and chest congestion caused by the common cold, infections, or allergies.
Dextromethorphan will not treat a cough that is caused by smoking, asthma, or emphysema.
Dextromethorphan and guaifenesin may also be used for other purposes not listed in this medication guide.

What is the most important information I should know about Mucinex DM (Dextromethorphan Guaifenesin)?

Do not give this medication to a child younger than 2 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.
Do not use a cough or cold medicine if you have used an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine (Parnate) within the past 14 days. Serious, life-threatening side effects can occur if you take cough or cold medicine before the MAO inhibitor has cleared from your body.
Do not use any other over-the-counter cough or cold medication without first asking your doctor or pharmacist. If you take certain products together you may accidentally take too much of one or more types of medicine. Read the label of any other medicine you are using to see if it contains dextromethorphan or guaifenesin.
Dextromethorphan will not treat a cough that is caused by smoking, asthma, or emphysema.

What should I discuss with my healthcare provider before taking Mucinex DM (Dextromethorphan Guaifenesin)?

Do not use a cough or cold medicine if you have used an MAO inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine (Parnate) within the past 14 days. Serious, life-threatening side effects can occur if you take cough or cold medicine before the MAO inhibitor has cleared from your body.
Ask a doctor or pharmacist if it is safe for you to take this medication if you have emphysema or chronic bronchitis.
FDA pregnancy category C. It is not known whether dextromethorphan and guaifenesin is harmful to an unborn baby. Before you take this medication, tell your doctor if you are pregnant or plan to become pregnant during treatment.
It is not known whether this medication passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
Artificially-sweetened liquid forms of cold medicine may contain phenylalanine. This would be important to know if you have phenylketonuria (PKU). Check the ingredients and warnings on the medication label if you are concerned about phenylalanine.

Mucinex DM Side Effects

What are the possible side effects of Mucinex DM (Dextromethorphan Guaifenesin)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using this medication and call your doctor at once if you have any of these serious side effects:

• severe dizziness, anxiety, restless feeling, or nervousness
• confusion, hallucinations; or
• slow, shallow breathing

Less serious side effects may include:

• dizziness
• headache
• skin rash or itching; or
• nausea, vomiting, or stomach upset

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Mucinex DM Interactions

What other drugs affect Mucinex DM (Dextromethorphan Guaifenesin)?

Before taking this medication, tell your doctor if you are using any of the following drugs:

• celecoxib (Celebrex)
• cinacalcet (Sensipar)
• darifenacin (Enablex)
• imatinib (Gleevec)
• quinidine (Quinaglute, Quinidex)
• ranolazine (Ranexa)
• ritonavir (Norvir)
• sibutramine (Meridia)
• terbinafine (Lamisil)
• medicines to treat high blood pressure; or
• an antidepressant such as amitriptyline (Elavil, Etrafon), bupropion (Wellbutrin, Zyban), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), imipramine (Janimine, Tofranil), paroxetine (Paxil), sertraline (Zoloft), and others

This list is not complete and there may be other drugs that can interact with dextromethorphan and guaifenesin. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

What should I avoid while taking Mucinex DM (Dextromethorphan Guaifenesin)?

This medication can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.
Avoid drinking alcohol. It can increase some of the side effects of this medication.
Avoid taking diet pills, caffeine pills, or other stimulants (such as ADHD medications) without your doctor’s advice. Taking a stimulant together with cough or cold medicine can increase your risk of unpleasant side effects.
Do not use any other over-the-counter cough or cold medication without first asking your doctor or pharmacist. Dextromethorphan and guaifenesin are contained in many medicines available over the counter. If you take certain products together you may accidentally take too much of one or more types of medicine. Read the label of any other medicine you are using to see if it contains dextromethorphan or guaifenesin.

Mucinex DM Dosage

How should I take Mucinex DM (Dextromethorphan Guaifenesin)?

Use this medication exactly as directed on the label, or as prescribed by your doctor. Do not use it in larger amounts or for longer than recommended. Cold medicine is usually taken only for a short time until your symptoms clear up.
Do not give this medication to a child younger than 2 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.
Measure the liquid form of this medicine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
Do not crush, chew, or break an extended-release tablet. Swallow the pill whole. It is specially made to release medicine slowly in the body. Breaking the pill would cause too much of the drug to be released at one time.
Dextromethorphan and guaifenesin granules should be sprinkled directly onto the tongue and swallowed right away.
Drink extra fluids to help loosen the congestion and lubricate your throat while you are taking this medication.
Talk with your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache, cough, or skin rash.
If you need to have any type of surgery, tell the surgeon ahead of time if you have taken a cold medicine within the past few days.
Store this medicine at room temperature, away from heat, light, and moisture.

What happens if I overdose on Mucinex DM (Dextromethorphan Guaifenesin)?

Seek emergency medical attention if you think you have used too much of this medicine.
Overdose symptoms may include feeling restless or nervous.

What happens if I miss a dose of Mucinex DM (Dextromethorphan Guaifenesin)?

Since cough or cold medicine is usually taken only as needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.
Edited from everydayhealth.com