Mucinex DM: What Are the Side Effects

Taking a dosage that’s too high may increase your risk of:

Mucinex: What Side Effects Can It Cause?

If mucus sits in your airways, bacteria can collect and grow there as well. That bacteria can lead to infection.

If you need help breaking up the mucus in your chest, you might consider a type of medication known as an expectorant.

Expectorants are used to treat chest congestion and cough. They help relieve chest congestion by breaking up mucus that’s stuck in your airways so you can cough it up.

The drug guaifenesin is currently the only expectorant that the Food and Drug Administration (FDA) has approved for over-the-counter (OTC) use. It’s found in many popular products, including Mucinex.

Guaifenesin is safe and well-tolerated. It’s quite possible that you can take it or Mucinex and have no side effects. In fact, most people do not. Still, they can cause side effects in some people.

There are multiple versions of Mucinex.

The products that contain guaifenesin are available as a liquid, a tablet, or granules. Products with DM in their names also include small amounts of the ingredient dextromethorphan, which helps suppress cough.

Mucinex products with guaifenesin as their main active ingredient are:

Children’s Cough Mini-Melts – Orange Creme Flavor
Children’s FreeFrom Cough & Mucus
Children’s Multi-Symptom Cold – Very Berry Flavor
DM Extended-Release Bi-Layer Tablets
Extended-Release Bi-Layer Tablets
Maximum Strength DM Extended-Release Bi-Layer Tablets
Maximum Strength Extended-Release Bi-Layer Tablets
Maximum Strength Fast-Max Chest Congestion Honey & Berry Flavor
Maximum Strength Fast-Max DM MAX
Maximum Strength Fast-Max DM MAX Honey & Berry Flavor
Maximum Strength Fast-Max Severe Congestion & Cough

Most other versions of Mucinex also contain guaifenesin but have acetaminophen as their main active ingredient.

The side effects that people can experience with Mucinex are usually mild to moderate. Some of the common side effects typically affect three different systems of the body.

The digestive system

Mucinex may cause the following digestive issues:

The nervous system

Mucinex may also cause:

The integumentary system (skin)

Mucinex can sometimes lead to a rash or hives.

Generally, if you use guaifenesin or Mucinex as directed, you should not have serious side effects. However, overuse or misuse can cause problems.

Taking a dosage that’s too high may increase your risk of:

dizziness
headache
severe gastrointestinal issues
kidney stones

Only people who are at least 12 years old should take Mucinex tablets. The FDA has not approved them for use in children younger than that.

However, children as young as 4 years old can use liquid Mucinex or Mucinex Mini-Melts. Mini-Melts are granules that you sprinkle on the tongue. These products are specifically marked for children on the packaging.

If your child is younger than 4 years old, speak with their doctor about the best way to treat their cough. Side effects of Mucinex in children are generally the same as they are in adults.

Overall, if you use Mucinex as directed, you probably will not have side effects. If you do have any, they’re usually mild.

There are some things you can do to help ease any bothersome side effects. For example, if Mucinex upsets your stomach, try taking it with food or a glass of milk.

Only use Mucinex for cough and chest congestion from mucus buildup. If you have another type of cough or are unsure what’s causing your cough, speak with a doctor before using Mucinex.

Also, check with a doctor before using Mucinex if you take other medications or have other medical conditions. They can help you avoid potentially harmful drug interactions.

Last medically reviewed on January 31, 2022

Mucinex DM: What Are the Side Effects?

The scene: You have chest congestion, so you cough and cough but still get no relief. Now, on top of the congestion, you also can’t stop coughing. You consider Mucinex DM because it’s made to treat both congestion and constant coughing. But before you use it, you want to know about the side effects.

Here’s a look at the active ingredients of this drug and the side effects they can cause. Keep reading to find out when the effects are most likely to happen, how to ease them, and what to do in the rare case that they’re severe.

Mucinex DM is an over-the-counter medication. It comes in an oral tablet and an oral liquid. It has two active ingredients: guaifenesin and dextromethorphan.

Guaifenesin helps loosen mucus and thin the secretions in your lungs. This effect helps make your cough more productive by allowing you to cough up and get rid of bothersome mucus.

Digestive system effects

Side effects of this drug can affect your digestive system. These effects are not common when you use the recommended dosage. However, if they do happen, they can include:

Nervous system effects

To help control your urge to cough, this drug works on receptors in your brain. In some people, this may also cause side effects. Side effects at the recommended dosage are uncommon but may include:

dizziness
drowsiness
headache

These side effects are rare. If you have these side effects and they are severe or don’t go away, contact your doctor.

Skin effects

Side effects on your skin are uncommon at a normal dosage, but may include an allergic reaction. This reaction typically causes a rash on your skin. If you have a skin rash after using Mucinex DM, stop using the drug and contact your doctor.

If the rash gets worse or if you notice swelling of your tongue or lips, or have any difficulties breathing, call 911 or local emergency services immediately. These may be signs of a severe allergic reaction.

Side effects from overuse

Side effects of Mucinex DM are most likely to happen if you use too much of this drug. That’s why you should only use it as recommended. Side effects from overuse are also more severe. They can include:

breathing problems
confusion
feeling jittery, restless, or agitated
extreme drowsiness
hallucinations
irritability
seizures
severe nausea
severe vomiting
kidney stones

Symptoms of kidney stones can include:

fever
chills
vomiting
severe, persisting pain in your back or side
burning pain during urination
foul-smelling urine
cloudy urine
blood in your urine

Stop taking this drug and contact your doctor immediately if you experience any of these severe side effects.