Expectorants vs. Mucolytics: What’s the Difference Between These Cough Medications?

Normally, mucus is helpful because it traps harmful germs, such as viruses and bacteria. Once trapped, you sneeze or cough the germs out of your body. But too much mucus can lead to discomfort and difficulty breathing.

Many respiratory conditions — from the common cold to cystic fibrosis — can cause thick, sticky mucus in the airways. And it’s common for people to take cough medications to help lessen this symptom. Expectorants and mucolytics are two classes of medications that people take to help with too much mucus.

Expectorants are commonly confused with mucolytics. But these two medications work differently and have different uses. Below, we’ll review expectorants and mucolytics and how these cough medications differ.

What are expectorants and mucolytics?

Expectorants are medications that help loosen mucus in the airways.

Examples of expectorants include:

• Ammonium chloride (found in some homeopathic cough remedies)

• Guaifenesin (Mucinex)

• Potassium iodide (SSKI)

• Mannitol (Bronchitol)

• Eucalyptus oil

• Sodium chloride (HyperSal) nebulizer solution — this medication also works like a mucolytic

Mucolytics are a class of medications that break down mucus. This makes it easier to clear mucus from the respiratory tract by coughing it up.

Examples of mucolytics include:

• Acetylcysteine (Mucomyst) nebulizer solution

• Dornase alfa (Pulmozyme) nebulizer solution

• Sodium chloride nebulizer solution — this medication also works like an expectorant

Good to know: Dextromethorphan (Delsym) is a popular cough medication. But it is neither an expectorant nor a mucolytic. Dextromethorphan doesn’t affect mucus at all. It’s a cough suppressant that lessens the urge to cough.

What are the biggest differences between expectorants and mucolytics?

Mucolytics and expectorants both work to reduce mucus, but they have some differences. This includes the way they work, the conditions they treat, and the dosage forms they come in. Some are available over the counter (OTC), while others require a prescription.

Below, we explain four differences between expectorants and mucolytics.

1. How they work

Mucolytics work by breaking down DNA and proteins in mucus. This makes it easier to cough up mucus.

Different mucolytics work in different ways. For example, acetylcysteine splits up the connections between mucus proteins. Dornase alfa breaks down DNA that’s found in thick mucus.

Expectorants work differently. They don’t directly break down mucus. Instead, they draw extra moisture into the airways. This thins out mucus and helps you cough it up or swallow it easier. As a result, there’s less mucus in your airways, and you can breathe a little better.

2. What conditions they treat

Expectorants are often used to treat short-term respiratory problems, like the common cold. There’s a good chance you’ve taken an expectorant when you’ve experienced chest congestion (a “wet” cough). They can be helpful if mucus production increases temporarily. But they can also be useful for managing chronic bronchitis, when the body isn’t able to clear mucus well on its own.

Mucolytics are prescribed for long-term respiratory problems that create thick, sticky mucus. They may help treat conditions such as cystic fibrosis and chronic obstructive pulmonary disease (COPD).

3. Dosage forms

Another difference between expectorants and mucolytics is their dosage forms.

Expectorants come in a variety of dosage forms. For example, guaifenesin is available in oral tablets, capsules, and liquids. But other expectorants, such as mannitol and sodium chloride, are available as nebulizer solutions to be inhaled.

Mucolytics are typically inhaled so that they can work locally in your airways. They’re usually breathed in through a nebulizer. Some prescribers may recommend taking acetylcysteine by mouth to help clear mucus as well. But this is considered an off-label use of the medication.

4. OTC availability

You’ve likely seen or purchased an expectorant while browsing the pharmacy for cold remedies. Guaifenesin is widely available OTC by itself and in combination with other cold medications. But not all expectorants are available OTC. Some, such as mannitol, are available by prescription only.

Mucolytics are available only with a prescription. Talk to your respiratory care team to learn more.

EXPERT PICKS: WHAT TO READ NEXT

• Does Mucinex work for cold symptoms? Research suggests that the popular expectorant Mucinex (guaifenesin) may not work for everyone.

• How is cystic fibrosis treated? Expectorants and mucolytics are two of the available treatment options. Read more about the medications used to treat cystic fibrosis.

• Can you take expectorants for bronchitis? Yes. Mucinex is one of several OTC remedies for this chest infection.

When should you not take an expectorant or a mucolytic?

In some cases, you should ask a healthcare professional before using an expectorant or a mucolytic. This is to make sure you’re getting the best and safest treatment for your health condition or symptoms.

When to avoid expectorants

If you have a chronic cough, talk to your primary care provider (PCP) before taking an expectorant. Chronic coughing can sometimes be caused by asthma, smoking, or bronchitis. Also check with them if you have a cough with an excessive amount of mucus. Your PCP may want to evaluate your symptoms or prescribe a treatment that’s better suited for your condition.

When self-treating with guaifenesin, contact your PCP if your cough lasts longer than 7 days. You should also contact them if your cough went away and came back, or if you develop a fever, rash, or headache that’s not going away. These symptoms could indicate a more serious infection that requires different treatments.

When to avoid mucolytics

If you’ve had an allergic reaction to mucolytics in the past, be sure to tell your prescriber. Dornase alfa isn’t recommended if you’re allergic to products made using Chinese hamster ovary cells, such as Humira (adalimumab).

You should also let your prescriber know if you have a history of asthma before using a mucolytic. Some people with asthma have experienced tightening of their airways after inhaling acetylcysteine.

How long do mucolytics and expectorants take to work?

In general, mucolytics and expectorants begin to work fast. How soon depends on things like the reason you’re taking it, how severe your symptoms are, and what dosage form you’re using.

After taking an expectorant, you can expect it to work quickly. Inhaled sodium chloride typically begins to work within 10 minutes. And oral guaifenesin begins to work about 30 minutes after taking it.

When inhaled, mucolytics can reach your airways quickly. Research in people with cystic fibrosis shows that dornase alfa works within 30 minutes. Studies also show that people who took this medication had significantly better lung function within 8 days.

In people with COPD taking inhaled acetylcysteine, most studies looked at lung function over periods of 4 months or longer. So it’s hard to say how fast it may start working, since researchers didn’t track this information. Regular treatment with acetylcysteine might improve lung function in some people living with COPD. And it may also lower the risk of flare-ups.

Can you combine expectorants and mucolytics?

Yes. Your respiratory specialist may recommend taking an expectorant and a mucolytic at the same time. They work differently to help clear the mucus from your airways. In fact, people with cystic fibrosis often use a combination of expectorants and mucolytics. Following your prescriber’s instructions closely can help you get the most out of your treatment.

Are other treatments typically combined with expectorants or mucolytics?

Depending on your health condition, you may take other medications in combination with an expectorant or a mucolytic. For example, people with cystic fibrosis often use a rescue inhaler, such as albuterol (ProAir, Proventil, Ventolin), to help open their airways before using an expectorant or mucolytic.

OTC expectorants are also commonly combined with other allergy, cold, and flu medications. These include fever reducers, nasal decongestants, and cough suppressants. Examples of these combination medications include:

• Guaifenesin / pseudoephedrine (Mucinex D)

• Guaifenesin / dextromethorphan (Mucinex DM)

• Guaifenesin / acetaminophen (Coricidin HBP)

Check with a healthcare professional before starting any new medications. They can help make sure you don’t take too much of the same types of medications. When purchasing an expectorant, read the OTC labels carefully so you know what medications are included.

Why trust our experts?

Written by:

Kristianne Hannemann, PharmD

Kristianne Hannemann, PharmD, is a licensed pharmacist in California. She has been a retail pharmacy manager and staff pharmacist for over 7 years and has contributed drug information content to different health companies.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Ferras Bashqoy, PharmD, BCCCP, BCPPS

Ferras Bashqoy, PharmD, BCCCP, BCPPS, is a clinical pharmacotherapy specialist in the Neonatal Intensive Care Unit (NICU) at Hassenfeld Children’s Hospital in New York City. His favorite part of the job is working with preterm newborns because they are strong and mighty despite their size.

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