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Ingredients: Guaifenesin
Average User Review Score
* Based on 191 reviews from across the web.

Guaifenesin INN /ɡwaɪˈfɛnᵻsɪn/ or guaiphenesin (former BAN), also glyceryl guaiacolate, is an expectorant drug sold over the counter and usually taken orally to assist the bringing up (expectoration) of phlegm from the airways in acute respiratory tract infections.

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Common adverse events from FDA database
* Extracted from FDA Adverse Event Reports for all drugs with the same active ingredients.

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Druginformer Identified Side Effects: Nightmare

Effectiveness Rating:     Overall Rating:

Posted By bold on February 18, 2017 @ 9:13 am

I have taken low-dose guaifenesin for years. Usually 100mg. Last night I took 200mg and had a nightmare waking up yelling HELP. I am NOT a nightmare person and this is a rare event. I will take it PRN because it helps with cough, drip, and keeps my vocal cords moist.

Druginformer Identified Side Effects: Fatigue, Depression

Posted By codeine/guaifenesin: This medi... in drugs.com on April 26, 2014 @ 12:00 am

This medicine helped with my cough but keeps me wired and wide awake and all I want to do is sleep because I am miserable. The pharmicist said it should help me sleep but apparently it has the opposit...

Druginformer Identified Side Effects: Insomnia

Posted By Anonymous in drugs.com on April 10, 2014 @ 12:00 am

I thought it helped a lot, not a miracle or anything of course. I felt better and did not have any sleep issues while using it. I hope that is just dependent on the user.

Druginformer Identified Side Effects: Respiration abnormal

Posted By guaifenesin: I have bronchial ... in drugs.com on April 1, 2014 @ 12:00 am

... my bronchials were closing up on me, I had to call my dr to tell him to get me prednisone. I took just a half tab of Guaifenesin before I went to bed, I woke up spasing, I couldn't breath. I had a d...

Druginformer Identified Side Effects: Feeling jittery

Posted By Anonymous in drugs.com on March 18, 2014 @ 12:00 am

Jittery and wide awake. But works great. Do not take before bed!

Druginformer Identified Side Effects: Dizziness, Nausea

Posted By Anonymous in drugs.com on February 23, 2014 @ 12:00 am

Took this medication for a chest cough before I went to bed. Woke up in the night with severe nausea and felt dizzy. Tried it again a week later and same happened. I know other people who swear by it....

Druginformer Identified Side Effects: None

Posted By Anonymous in drugs.com on January 31, 2014 @ 12:00 am

This is a better cold and cough medicine combination than the others. I have been using it for about 5 years, but only when I get a cold and once in awhile. Also for shortness of breath since a cold t...

Druginformer Identified Side Effects: None

Posted By Anonymous in drugs.com on January 28, 2014 @ 12:00 am

This worked for me when nothing else would

Druginformer Identified Side Effects: Anxiety, Headache, Feeling jittery, Insomnia, Abnormal sleep-related event

Posted By Anonymous in drugs.com on January 21, 2014 @ 12:00 am

I took this medicine (2 pills) at 9 PM. I went up to bed at 10:30 and was not able to sleep all night. I tossed and turned, felt wide awake, and I am now at work. It did clear my sinuses and my se...

Druginformer Identified Side Effects: Headache, Pain, Sleep disorder, Pneumonia

Posted By Anonymous in drugs.com on January 6, 2014 @ 12:00 am

Went to the ER this morning with pneumonia. Was prescribed Cheratussin. Has helped cough a lot. Relieved some pain in ribs. But it did give me a headache and looks like no sleep.

* Warning: The facts and figures contained in these reports are accurate to the best of our capability; however, our metrics are only meant to augment your medical knowledge, and should never be used as the sole basis for selecting a new medication. As with any medical decision, be sure to work with your doctor to ensure the best choices are made for your condition.

* About FAERS: The FDA Adverse Event Reporting System (FAERS) is used by FDA for activities such as looking for new safety concerns that might be related to a marketed product, evaluating a manufacturer's compliance to reporting regulations and responding to outside requests for information. Reporting of adverse events is a voluntary process, and not every report is sent to FDA and entered into FAERS. The FAERS database may contain duplicate reports, the report quality is variable, and many factors may influence reporting (e.g., media attention, length of time a drug is marketed, market share). For these reasons, FAERS case reports cannot be used to calculate incidence or estimates of risk for a particular product or compare risks between products.