Guaifenesin / pseudoephedrine and Drowsiness: What Users Say

• Tin...
• Taken for less than 1 month
• November 12, 2016

For Cough and Nasal Congestion "Mucinex works, allows your cough to loosen up all the mucus you feel weighing your chest down. I was congested for a good month and on antibiotics, used over-the-counter drugs, and nothing was working for me. I decided to use Mucinex, at this point, I had nothing to lose. Within the first couple of hours, this medication allowed the mucus to cough up easier. The downfall is, don't take it at night as it will keep you up and still continue to increase your cough in order for you to get rid of your congestion! My advice: take it early in the morning with breakfast, and if you can't sleep, drink lots of fluids so you can get it out of your system faster."

• Jus...
• December 16, 2016

For Cough and Nasal Congestion "Avoid. I feel like I am on speed. In fact, I told this to my husband the night before, when I couldn't sleep. 9 a.m., and I am currently on night 3 of sleeplessness, as I only now thought to look up side effects. I am livid. Who on earth would want to be unable to sleep when sick?!? I'm mad my husband didn't buy the medicine I requested! He actually told the pharmacist my symptoms, and this is what was recommended. It hasn't done anything except keep me awake for 3 days. I've been congested with terrible sinus headaches. This medication hasn't touched it... As a result, I still have this sinus congestion with terrible pressure headaches, only now I also feel extremely anxious, alert, and my eyeballs feel as though they're going to shrivel up."

• Jen...
• February 21, 2017

For Cough and Nasal Congestion "Cleared up my congestion. I too didn't realize it would leave me sleepless. I am sick and want to sleep so badly but cannot. It's 5 am. I have slept 2 hours in the last 24 hours due to this medication. I feel I should be sleeping off this cold and cannot. I agree with the other commenters. Take this only in the morning!!!"

• Cha...
• March 5, 2015

For Cough and Nasal Congestion "The medicine itself works to relieve chest/nasal congestion, but it keeps me from sleeping. First night, I was thinking maybe it was because I was traveling, but the second night, same thing, and it's almost like it automatically wakes you at around 2 am. My second dose yesterday had me jittery and groggy during the day. Don't know if I will continue to take this or not. I need sleep!"

• Why...
• April 17, 2013

For Cough and Nasal Congestion "Yeah. If you want a good decongestant, Mucinex D is for you. Took my first dose at 4 PM, warned that it could cause 'sleeplessness.' Thought I was in the clear, but low and behold, I am here writing this review to the world after that one dose. Current time: 7:15 AM. Taking another just to keep me up for class today. Hurray."

• Unh...
• April 21, 2017

For Cough and Nasal Congestion "This is my second day of using Mucinex. At this point, I'm not sure why my doctor recommended it. I never did have congestion, just a sore throat. Anyway, I'll not take it anymore, it's 1:00 a.m., I'm totally exhausted and cannot sleep. Last night it was 12:30 or so, and I finally went to sleep. I'm used to falling asleep around 9:30. I do take sleeping pills, and I just took my dose of those, hope it puts me to sleep. Otherwise, how do you make it through the next day? I just read the label, guess I missed before that it can cause sleeplessness, or I wouldn't have taken it at all. It's expensive and another drug going in the garbage can!"

• Spa...
• Taken for less than 1 month
• November 3, 2017

For Cough and Nasal Congestion "Recommended by a doctor who knows I don't like to take medication, I went to him with a bad cold, stuffed nose, and sore throat. Took 2 pills at about noon and symptoms cleared up amazingly quickly. Took 2 about 11:30 at night, went to bed, and now it's almost 2 AM and I'm still wide awake. I wish the doctor had warned me, and there definitely should have been a warning on the box...when one is sick, one should be able to rest, and this is the opposite, and I have a full workday tomorrow and should be at work by 9. I found this site trying to figure out why I am so wide awake."

• Aly...
• July 20, 2016

For Cough and Nasal Congestion "I took the liquid version at work one day to help with my cough, and it worked better than I thought and faster than the pills. Although, I was sleepy all day, and I don't recall reading the words 'may cause drowsiness' on the bottle. Perhaps they were there, and I did not see them."

• Cfe...
• Taken for less than 1 month
• November 19, 2017

For Cough and Nasal Congestion "So, I am not one to take medications much, and I don't take any medicine on a regular basis, but Mucinex D is definitely a must in my medicine cabinet for that severe once-a-year bug. It CAN cause sleeplessness in the night, but with that in mind, I usually take it at 7 a.m. and 7 p.m. if I even take a second dose at all during a 24-hour period. I cannot sleep when I get a cold, and though this medication can keep me awake, it is still a better alternative to suffering through a night of clearing my throat and getting up to blow my nose multiple times. For the record, I only take 1 at a time and have quick results with no other side effects besides the sleeplessness. Choose wisely, y'all, this stuff can be a miracle if you need one."

• DLK...
• Taken for less than 1 month
• September 18, 2021

For Cough and Nasal Congestion "Took the normal dose at 8 pm, even though I read on the label that it may cause sleeplessness. I was still up at 4 am, tossing and turning, then at some point, finally fell asleep for a few hours. My symptoms disappeared overnight, and I feel great today, but I'll never take this close to bedtime again."

• SSF...
• Taken for less than 1 month
• February 20, 2025

For Cough and Nasal Congestion "I highly recommend Mucinex D. First of all, I am not tolerant of many cold/allergy medicines. I was prescribed Mucinex D (2 pills every 12 hours) for my chest and nasal congestion. It seems everything I take affects me with anxiety, drowsiness, dry mouth, nausea, or something. So, to be safe, I took only 1 tablet to start. Within 1/2 hour, my cold symptoms were so much better, and I had no side effects from the pill. Then, 6 hours later, my cold symptoms started getting bad again. So, I took 1 more at 6 hours. Long story short, I have been taking Mucinex D for 3 days. But my schedule is 1 tablet every 6 hours, instead of 2 every 12 hours (still at the limit of 4 in 24 hours). I have had no trouble sleeping (except for the cough and nasal stuff). I am not sleepy, or anxious, or anything. In fact, I feel great. It does seem to be an appetite suppressant too...bonus! I am so glad I took the chance of making my own dosing schedule. It works!"

• Bla...
• January 30, 2016

For Cough and Nasal Congestion "Loosened phlegm, but makes you feel very dizzy, drowsy, and dehydrated."

• Awa...
• Taken for less than 1 month
• October 19, 2015

For Cough and Nasal Congestion "It helps with nasal congestion better than other medicine. But it gave me a terrible headache and no sleep all night. I stopped using it after 2 doses."