Concerned About Taking Too Much Mucinex (Guaifenesin) At Once

In our latest question and answer, our pharmacist discusses concerns someone has after taking too much Mucinex by crushing an extended-release tablet.


I crushed Mucinex 600mg and put it in my feeding tube. Afterward, I read about it and it should not be crushed. It's been about an hour and a half. What should I do?

Asked by Fatty On Jan 14, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jan 16, 2023
Last updated Jul 18, 2024

Key points

  • Mucinex is considered to be a relatively safe drug, with side effects only occurring infrequently when used at recommended dosages.
  • Excessive dosages or long-term dosing of Mucinex has been linked with nausea, diarrhea, headache, and kidney stones, but these appear to occur only rarely.
  • There are very few published case reports documenting Mucinex overdoses being a contributing factor to serious side effects or death.
  • Animal studies report an LD50 (lethal dose in 50% of a test population) of Mucinex is around 1510mg/kg, meaning, for most individuals, extremely large single doses would need to be ingested for risk of death.


Thanks for contacting us! As you allude to in your question, brand-name Mucinex tablets should not be crushed as they as designed to be extended-release. Crushing these tablets will destroy the extended-release mechanism and cause the entire dose to be released at once. This is a topic we have covered in one of our previous answers.

Crushing extended-release medications can greatly increase the risk of side effects since you are getting a higher dose than intended, all at once. The good news as it concerns Mucinex (guaifenesin), however, is that it is a relatively benign drug when it comes to side effects and is usually very well tolerated.

Studies report that serious side effects with Mucinex are quite rare and cases of overdose are even rarer, although there have been certain symptoms reported with taking high doses for extended periods of time.

Additionally, the amount you took (600mg at once time) is not much more than the recommended dosing for the drug, which is either 200-400mg of immediate-release guaifenesin per dose or 600-1,200mg of extended-release guaifenesin per dose.

The risk of you experiencing serious side effects from the dose you took is very low, and while I'll talk more about Mucinex dosing in the next section, it is important to note that even though Mucinex is considered a relatively safe drug, if you feel you have overdosed and/or are feeling symptoms, it is important to seek medication attention, call 911 or at the very least, contact Poison Control at or 1-800-222-1222 for assistance for your specific situation.

Mucinex Dosing

Mucinex (guaifenesin) is recommended to be taken as follows:

  • Immediate-Release Guaifenesin: 200-400mg by mouth every 4 hours as needed. Maximum daily dose 2,4000mg per day
  • Extended-Release Guaifenesin: 600-1,200mg by mouth every 12 hours as needed. Maximum daily dose 2,4000mg per day

The above dosing is for adults, adolescents, and children 12 years and older.

Mucinex Overdose Discussion

As mentioned, Mucinex is considered a relatively safe drug and has a low risk of overdose.

Side effects with Mucinex are considered to occur only infrequently, and if they do, are usually not serious. They rarely occur when taking recommended dosages.

Nevertheless, higher than recommended doses have been reported to cause:

  • Abdominal pain
  • Headache
  • Vomiting
  • Diarrhea

I will say that excessive dosages for long periods of time have been linked to increasing the risk of kidney stone formation (nephrolithiasis), but typically when this has been reported, there have been other factors likely at play.

When talking about drugs and overdosing, there is always that concern about what the potential side effects could be, or if there is any risk of death.

I could only find 2 case studies ever (such as this one that was published in the Journal of Analytical Toxicology) that suggest that a Mucinex overdose was a contributing factor to death. In these cases too, there were likely other contributing factors and drugs.

In animal studies, the LD50 value (which is a measure of the dose of a substance that would be lethal to 50% of a test population, usually animals, and is used to determine the toxicity of a substance) has been reported to be 1510 mg/kg. To translate this to a 150-pound human, the LD50 dose would be over 100,000mg (166 tablets of Mucinex 600mg).

The point I'm trying to make here is that Mucinex is just not a drug where there is a large risk of serious side effects or death occurring after a small overdose (like taking a crushed 600mg tablet).

Now, everyone's medical situation is different, and anytime you suspect an overdose, I do recommend seeking some sort of medical attention, whether that is going to the emergency room (especially if you are symptomatic) or contacting Poison Control. They can give you more specific guidance for your situation.

On the surface though, I wouldn't expect you to experience any serious complications from taking one crushed Mucinex tablet.

Final Words

I hope you found this helpful and please contact us again if anything else comes up!


  • Guaifenesin Monograph, PubChem
  • Guaifenesin- and ephedrine-induced stones, PubMed
  • Swift onset of central nervous system depression and asystole followingan overdose of Guaifenesin, PubMed
  • Acute intoxication with guaifenesin, diphenhydramine, and chlorpheniramine, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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