Mucinex vs. Benadryl: Which Works Better for Allergies?

There are many allergy medications available to tackle that runny nose and sneezing. And some of these medications can also help treat certain cold symptoms. Benadryl (diphenhydramine) is an example of a medication that can help with both.

But what about the cough medication Mucinex (guaifenesin)? Can this medication also help when it comes to allergies? Mucinex isn’t usually a go-to option for allergy relief. It's mainly used for chest congestion. But if your allergy symptoms include a cough, Mucinex might come in handy.

And if you need it, is it safe to combine Mucinex and Benadryl?

What are Mucinex and Benadryl?

Mucinex and Benadryl are both over-the-counter (OTC) medications. But they contain different active ingredients.

Mucinex is traditionally a brand-name product for guaifenesin (an expectorant). But the name “Mucinex” also refers to a line of many OTC pills, oral liquids, and throat sprays in the cold-and-flu aisle. So if you see the word Mucinex on a box, be sure to read the OTC label. It may or may not have guaifenesin in it. And it could have more than one active ingredient in it.

Benadryl is a brand name for the antihistamine diphenhydramine. It comes in many different forms, such as liquid, tablets, and creams. Similar to Mucinex, Benadryl is also a name for a line of OTC products. All Benadryl products contain diphenhydramine. But some contain other ingredients, too. Be sure to carefully read the package’s label when choosing a product.

For this article, when we use the word “Mucinex,” we’ll be talking about guaifenesin-only products. And when we say “Benadryl,” we’ll be referring to oral medications that only contain diphenhydramine.

How effective are Mucinex and Benadryl for allergies?

Benadryl and other antihistamines are a better option than Mucinex for managing allergy symptoms. This is because of how each medication works.

Benadryl works by blocking the chemical histamine in your body. When your body senses a foreign invader, it releases many chemicals, including histamine, to combat the attack. But sometimes, your body can view harmless substances, like pollen or animal dander, as a threat.

EXPERT PICKS: WHAT TO READ NEXT

• Comparing options: Learn about the differences between allergy medications so you can choose the right one for you.

• Allergy medications for cold symptoms: Find out which allergy medications can be useful if you have a cold.

• Medications for postnasal drip: Lots of things can lead to postnasal drip, and the best treatment depends on the cause. Learn about medications for postnasal drip.

Once histamine is released, it causes allergy symptoms, such as sneezing and a runny nose. Taking Benadryl can help lessen your body’s reaction to histamine and relieve your symptoms.

Mucinex can help relieve cough caused by postnasal drip. This is when mucus from a runny nose drips down the back of your throat. Mucinex draws moisture into your airways to help thin down mucus. This helps you cough up mucus more easily.

Mucinex doesn’t target the cause of allergies. But it’s common to have postnasal drip as an allergy symptom. So if you’re experiencing this symptom, Mucinex may help relieve it. Just keep in mind that it doesn’t help with other allergy symptoms, such as sneezing or watery eyes.

What are the known side effects of Mucinex and Benadryl?

Mucinex is generally well tolerated. But it can cause headaches, nausea, or dizziness for some people. These side effects are relatively uncommon, though. Contact a healthcare professional if you experience any bothersome side effects after taking Mucinex.

Side effects with Benadryl are more common. It’s most known for causing drowsiness. That’s why it’s recommended not to drive or perform other activities that require focus after taking it.

Other Benadryl side effects include:

• Dizziness

• Dry mouth

• Trouble urinating

• Constipation

• More active or excited behavior (more common in children)

What interactions do Mucinex and Benadryl have?

Mucinex has no significant interactions. It’s considered safe to take with other medications.

You should, however, be careful combining Benadryl with other medications or substances that have similar side effects. If you take medications that cause drowsiness, such as opioids, Benadryl can cause or contribute to excessive drowsiness. The same is true if you drink alcohol while taking Benadryl.

Similarly, if you take medications that cause constipation or dry mouth, such as oxybutynin, Benadryl could worsen these side effects.

This isn’t a full list of all possible Benadryl interactions. Share a list of medications that you take with a pharmacist. They can let you know if you can safely take Benadryl.

Can you take Sudafed and Benadryl at the same time?

Yes, it’s safe to take Sudafed (pseudoephedrine) and Benadryl at the same time. In fact, these medications used to be available together in a combination product. There are no known interactions between Sudafed and Benadryl.

But be aware that having trouble urinating is a possible side effect for both medications. If you have a history of urination problems or have an enlarged prostate, ask a healthcare professional before taking Sudafed and Benadryl. Stop taking them if you experience this side effect.

Can you take Delsym and Benadryl at the same time?

Yes, you can take Delsym (dextromethorphan) and Benadryl at the same time. This combination isn’t known to interact with each other.

Just make sure the Delsym product you choose isn’t a combination medication. Taking this with Benadryl could cause you to accidentally take two antihistamines at once. For example, Delsym Nighttime Cough contains dextromethorphan, acetaminophen (a pain reliever), and triprolidine (an antihistamine). You shouldn’t take more than one antihistamine at a time.

Can you take Mucinex and Benadryl together?

Yes, you can take Mucinex and Benadryl together. There are no interactions between them. But if you’re looking for a combination product that contains both medications, it’ll be tough to find one. It’s not typical to see their active ingredients (guaifenesin and diphenhydramine) together in one product.

It’s more common to see doxylamine (a different antihistamine) included in “nighttime” cold and flu medications. And Mucinex-brand nighttime products usually contain triprolidine as their antihistamine component.

So if you want to take Mucinex and Benadryl together, you’ll likely need to purchase two separate products.

What are the typical dosages for Mucinex and Benadryl?

Both Mucinex and Benadryl are oral medications. They come as tablets, capsules, and a liquid. Benadryl also comes as a chewable tablet.

Adults and children ages 2 and older can take Mucinex. The amount you take depends on your age. But typically, you can take an age-appropriate dose every 4 hours as needed. There’s also an extended-release (ER) version of Mucinex available for people ages 12 and older. You should only take a dose of Mucinex ER once every 12 hours.

Benadryl’s OTC label only provides dosages for adults and children ages 6 and older. If needed, a healthcare professional can provide a safe dose for children under age 6. The amount of Benadryl you should take is based on you or your child’s age. But you can take a dose every 4 to 6 hours as needed. It’s important to discuss what a safe daily dose of Benadryl is for you with your healthcare team. Too much Benadryl can be dangerous.

How to save on Mucinex and Bendaryl

There are many ways to save on Mucinex and Benadryl, which are available as both brand-name and generic medications. By having a healthcare professional write a prescription for Mucinex or Benadryl, GoodRx can help you save on the average retail price.

Generic Benadryl at certain pharmacies may be as low as $2.96 with a free GoodRx discount. And generic Mucinex may be as low as $18.59.

Frequently asked questions

Why trust our experts?

Written by:

Timothy Aungst, PharmD

Timothy Aungst, PharmD, has worked in pharmacy practice for the past decade with different roles and responsibilities. He has served as an associate professor of pharmacy practice for almost a decade, a clinical pharmacist in outpatient cardiology management, and now in home healthcare.

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:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Our editorial standards

Meet our experts