Guaifenesin is an expectorant used for wet cough. It helps loosen phlegm in the throat and chest so you can cough it up more easily. Guaifenesin is an immediate-release medication that's available as a tablet and liquid solution. It's taken by mouth, typically every 4 hours, by adults and children. Most people experience few to no side effects after taking this medication as directed. Guaifenesin can be found under multiple brands (e.g., Robafen, Geri-Tussin) and as a generic medication.
Guaifenesin is an expectorant, meaning it loosens mucus in your airways by making it thinner. This makes it easier to cough out mucus and help clear chest congestion.
| Common Brands | Mucinex, Geri-Tussin, Children's Mucus Relief, Pharbinex, Robafen |
|---|---|
| Drug Class | Expectorant |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | Lower-cost generic available |
| Availability | Over-the-counter |
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Side effects aren't common. See Other Side Effects.
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Guaifenesin can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Guaifenesin is an expectorant, which is found in many other over-the-counter products. Using more than one product containing the same ingredients can lead to an accidental overdose that can be dangerous.
If you're not sure whether you're taking a medication with guaifenesin in it, talk to your care team. To prevent an accidental overdose, follow the specific product instructions on the package carefully. If you think that you or your child might’ve accidentally taken too much guaifenesin, call a Poison Center at 1-800-222-1222 right away even if you aren't completely sure.
Guaifenesin tablets and solutions made by different manufacturers might have different directions, age limits, and strengths. It's important to follow the specific product instructions on the package or the directions given by your care team.
Some examples are listed below:
Generic 100 mg/5 mL solution, generic 200 mg tablets, generic 400 mg tablets
Please note: Guaifenesin 200 mg tablets are only for people ages 6 years and older. Guaifenesin 400 mg tablets are only for people ages 12 years and older.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
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The manufacturers of Guaifenesin immediate-release tablets don't specify whether you can crush them or not. Some Guaifenesin tablets are scored, meaning they have a line down the middle where you can split them in half. This is helpful if you only need to take one-half of a tablet. Follow the directions on the product you have carefully. Consider taking Guaifenesin oral liquid or solution if you have trouble swallowing the tablets.
Both extended-release (ER) guaifenesin and immediate-release (IR) guaifenesin are taken by mouth to treat chest congestion. The main difference between them is how long the effects last. Guaifenesin ER is a longer-lasting medication so you can take it once every 12 hours. But the effects of guaifenesin IR don't last as long; this medication can be taken once every 4 hours. Another difference is who can take it. Guaifenesin ER contains a higher dose of the medication and should only be taken by people ages 12 years and older. Guaifenesin IR comes as an oral solution and the dose can be adjusted for children as young as 2 years old, if approved by their pediatrician. Ask your pharmacist if you have more questions about the differences between guaifenesin ER and guaifenesin IR.
Whether you choose guaifenesin ER and guaifenesin IR depends on your need and personal preference. Both formulations of the medication are bioequivalent, which means they work similarly well to ease chest congestion. But you might consider guaifenesin ER if you want a medication that's longer lasting. This is because the effects of guaifenesin ER can last up to 12 hours, whereas the effects of guaifenesin IR might only last 4 hours. On the other hand, guaifenesin IR might be a better option if you're giving this medication to a child. Guaifenesin IR comes in an oral solution that can be given to children as young as 2 years old. But guaifenesin ER is for people ages 12 years and older. Ask your pharmacist if you're not sure whether guaifenesin ER or guaifenesin IR is a better option for you.
There's limited research on how long it takes for Guaifenesin to start working. One study showed that your body absorbs most of this medication 30 minutes after a dose. It's thought to work within 15 to 30 minutes after a dose. But other studies suggest that people might not notice a difference in their cough after taking Guaifenesin. If your cough lasts more than 7 days or gets worse, make sure to let your primary care provider know before continuing this medication.
In general, immediate-release Guaifenesin tablets and oral solutions are taken by mouth once every 4 hours as needed. Keep in mind that different formulations of Guaifenesin might have different directions, strengths, and dosage limits. Talk with your healthcare team if you're not sure how often you should take Guaifenesin.
You should wait until you're fully recovered and no longer taking Guaifenesin before drinking alcohol. While alcohol doesn't have known interactions with this medication, it's best to avoid drinking alcohol while you're fighting off an illness like the cold or flu. This is because alcohol can weaken your immune system, which makes it harder for your body to recover.
Guaifenesin doesn't make you sleepy or keep you awake. You should be able to take it during the day without feeling sleepy or at night without being kept awake.
There's limited research on how Guaifenesin might affect pregnancy. Speak with your gynecologist about the risks and benefits of taking Guaifenesin for your cough during pregnancy. Although most studies found that this medication isn't likely to raise the risk of birth defects, some studies showed otherwise. Ask your gynecologist about safer options to relieve your cough if you're pregnant.
