Mucinex Fast-Max Dosages: Your GoodRx Guide

If you’ve got a cold or the flu, you probably want some relief ASAP. Many over-the-counter (OTC) products can help. The makers of Mucinex offer a popular line of products called  Mucinex Fast-Max. These combination medications allow you to treat multiple symptoms with one product.

But if you’re considering the Mucinex Fast-Max line, keep in mind each product may have different instructions for taking it. And knowing how much to take can help keep you safe. In this guide, we’ll discuss typical Mucinex Fast-Max dosages for adults and children, as well as what to do if you think you took too much.

What’s the typical Mucinex Fast-Max dosage for adults?

The typical Mucinex Fast-Max dosage for adults is 2 pills or 20 mL by mouth every 4 hours as needed. You shouldn’t take more than 6 doses (12 pills or 120 mL) in 24 hours. As we’ll go over below, the active ingredients vary between products. So be sure to read all OTC labels before taking a dose.

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If you’re taking a liquid version of Mucinex Fast-Max, use the included dose cup to measure your dose. A kitchen spoon won’t give you an accurate dose and can result in you taking too much or too little medication.

Below, we detail the active ingredients and dosages for each Mucinex Fast-Max product.

Good to know: Many Mucinex Fast-Max products contain the nasal decongestant phenylephrine. The FDA has determined that oral phenylephrine doesn’t relieve nasal congestion. While it’s not harmful for most people to take, there are alternatives that work better.

Mucinex Fast-Max Cold and Flu dosage for adults

Mucinex Fast-Max Cold and Flu comes as oral tablets, oral capsules, and an oral liquid. The active ingredients included in every pill or 10 mL are:

• 325 mg of acetaminophen (a pain reliever and fever reducer)

• 10 mg of dextromethorphan (a cough suppressant)

• 200 mg of guaifenesin (an expectorant)

• 5 mg of phenylephrine (a nasal decongestant)

The typical Mucinex Fast-Max Cold and Flu dosage for adults is 2 pills or 20 mL by mouth every 4 hours as needed. Don’t take more than 6 doses (12 pills or 120 mL) in 24 hours.

Good to know: Mucinex Fast-Max Cold, Flu, and Sore Throat products contain the same active ingredients as Mucinex Fast-Max Cold and Flu products. They also have the same dosage instructions. And they come in the same dosage forms: oral tablets, oral capsules, and an oral liquid.

Mucinex Fast-Max Severe Congestion and Cough dosage for adults

Mucinex Fast-Max Severe Congestion and Cough comes as oral tablets and an oral liquid. The active ingredients included in every tablet or 10 mL are:

• 10 mg of dextromethorphan

• 200 mg of guaifenesin

• 5 mg of phenylephrine

The typical Mucinex Fast-Max Severe Congestion and Cough dosage for adults is 2 tablets or 20 mL by mouth every 4 hours as needed. Don’t take more than 6 doses (12 tablets or 120 mL) in 24 hours.

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Mucinex Sinus-Max Pressure, Pain, and Cough dosage for adults

Mucinex Sinus-Max Pressure, Pain, and Cough is available as oral tablets. Each tablet contains:

• 325 mg of acetaminophen

• 10 mg of dextromethorphan

• 200 mg of guaifenesin

• 5 mg of phenylephrine

The typical Mucinex Sinus-Max Pressure, Pain, and Cough dosage for adults is 2 tablets by mouth every 4 hours as needed. Don’t take more than 12 tablets in 24 hours.

Mucinex Sinus-Max Severe Congestion and Pain dosage for adults

Mucinex Sinus-Max Severe Congestion and Pain is available as oral tablets and an oral liquid. The active ingredients included in every tablet or 10 mL are:

• 325 mg of acetaminophen

• 200 mg of guaifenesin

• 5 mg of phenylephrine

Mucinex Sinus-Max Severe Congestion and Pain also comes as oral capsules. But the capsules have slightly different active ingredients from the oral tablets and liquid:

• 325 mg of acetaminophen

• 10 mg of dextromethorphan

• 5 mg of phenylephrine

The typical Mucinex Sinus-Max Severe Congestion and Pain dosage for adults is 2 pills or 20 mL by mouth every 4 hours as needed. Don’t take more than 6 doses (12 pills or 120 mL) in 24 hours. This dosage is the same for all three versions of the product (despite the different active ingredients).

What’s the typical Mucinex Fast-Max dosage for children?

Adolescents age 12 and older can follow the adult dosages for all Mucinex Fast-Max products as detailed above.

Children under 12 years old shouldn’t take these products. Many other Mucinex combination products and other cough and cold medications are safe for younger kids. If you’re unsure what to pick, your pharmacist can help you choose an appropriate product for your child.

Why shouldn’t children under 12 take Mucinex Fast-Max?

Children under 12 shouldn’t take Mucinex Fast-Max because they’re fixed-dose combination medications. This means the dose of the active ingredients can’t be changed. Younger children often need to take lower doses of the medications included in Mucinex Fast-Max. Giving one of these products to a child under 12 may result in them taking too much of one or more active ingredients.

Are there any dosage adjustments for health conditions?

Some medications require dosage changes if you have certain health conditions, such as liver or kidney disease. This isn’t the case for Mucinex Fast-Max. But sometimes you may need to avoid these products altogether. This is usually because certain situations or health conditions can raise the risk of serious side effects.

Ask a healthcare professional before taking Mucinex Fast-Max if you:

• Have heart problems, such as heart disease

• Have high blood pressure

• Have thyroid problems

• Have liver disease

• Have diabetes

• Are pregnant

• Are breastfeeding

• Have a chronic cough caused by smoking, asthma, or chronic obstructive pulmonary disease (COPD)

• Take other medications that contain acetaminophen

• Have taken a monoamine oxidase inhibitor (MAOI), such as selegiline (Emsam, Zelapar), in the last 2 weeks

• Have excessive amounts of mucus with your cough

This isn’t a complete list of who should avoid Mucinex Fast-Max products. It’s always a good idea to talk to your healthcare team first to make sure these products are safe for you to take.

What should you do if you take too much Mucinex Fast-Max?

Accidentally taking an extra dose of Mucinex Fast-Max isn’t likely to cause serious harm to most people. But you may have more side effects than usual. Side effects vary depending on the active ingredients in your Mucinex Fast-Max product. But common ones include dizziness, trouble sleeping, and nausea.

Taking an excessive amount of Mucinex Fast-Max can be more serious. Too much acetaminophen can cause liver damage. Too much phenylephrine can increase your blood pressure and heart rate. And too much dextromethorphan can cause hallucinations, seizures, or even death.

If you or a loved one has taken too much Mucinex Fast-Max, contact a healthcare professional or call Poison Control at 1-800-222-1222. If you notice any life-threatening symptoms, such as loss of consciousness, call 911 or go to the closest ER.

How to save on Mucinex Fast-Max

There are ways to save on Mucinex Fast-Max, which is available as a brand-name and generic medication. If your healthcare professional writes a prescription for Mucinex Fast-Max, GoodRx can help you save up to 80% off the average retail price.

The price of 1 bottle of brand-name Mucinex Fast-Max Cold and Flu at certain pharmacies is as low as $14.37 with a free GoodRx discount. And the price of 1 bottle of brand-name Mucinex Fast-Max Cold, Flu and Sore Throat may be as low as $.

Why trust our experts?

Written by:

Sarah Morin, RPh

Sarah Morin, RPh, has been a registered pharmacist for over 25 years. She started out as a hospital pharmacist, working at Rhode Island Hospital and then at the University of Connecticut Health Center.

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:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

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