- This article has been written by Dr. Darshan Shingala (M.D, MPH) – a qualified and practicing medical doctor – for maximum factual accuracy and reliability.
Mucinex is the commercial brand name for the drug called guaifenesin.
Mucinex is used to clear phlegm and mucus from the pulmonary system and airways to relieve nasal and chest congestion caused by allergies or the common cold.
But can Mucinex keep you awake at night or make you sleepy?
Guaifenesin found in regular Mucinex may keep some individuals awake but paradoxically may cause other individuals to feel sleepy. Mucinex D and Mucinex DM are more likely to cause insomnia due to their respective inclusion of pseudoephedrine and dextromethorphan.
The rest of this article explains in more detail how Mucinex, Mucinex D, and Mucinex DM affects sleep based on scientific research.
I have also included 6 tips for sleeping better when taking Mucinex based on my own professional experience as a practicing medical doctor.
Always consult with your own doctor if you are having trouble sleeping, have a pre-existing medical condition, or plan to change your medication.
How Does Mucinex Keep You Awake?
Guaifenesin is available singularly as Mucinex (guaifenesin) and in combination with other ingredients.
Examples are Mucinex D (guaifenesin/ pseudoephedrine), and Mucinex DM (guaifenesin/ dextromethorphan).
Evidence from scientific literature suggests that there are ingredients (guaifenesin, pseudoephedrine, and dextromethorphan) in all varieties of Mucinex that may be associated with sleep disturbance.
Theoretically, the content of Mucinex has the ability to impair the reflexes and negatively influence alertness – resulting in sleepiness.
However, some people have reported that they have difficulty sleeping after taking Mucinex.
A more detailed description of how each type of Mucinex and their main active ingredients can affect your sleep is outlined below:
The active ingredient in Mucinex – guaifenesin – belongs to the drug class of expectorants that aids in loosening mucus accumulation in the lungs and helps to relieve symptoms of coughing and nasal congestion .
Guaifenesin – and therefore the original version of Mucinex – may cause wakefulness in some individuals whilst others have reported feeling sleepy.
More research is required to identify a clear link.
Mucinex D is a therapeutic mixture of two drugs: guaifenesin and pseudoephedrine.
Pseudoephedrine belongs to the drug class of decongestants.
Pseudoephedrine causes constriction of the sinus blood vessels and the adjacent smooth muscles – leading to decongestion and the reduction of inflammation in the body.
In addition to this, it also helps in thinning the mucus membranes and permitting mucus drainage from the synovial cavities [2, 3].
The pseudoephedrine in Mucinex D can keep you awake.
Mucinex DM is a therapeutic mixture of two drugs: guaifenesin and dextromethorphan.
Dextromethorphan belongs to the drug class of antitussives, and it helps in suppressing the cough by decreasing the activity of the cough center in the brain .
Dextromethorphan may keep you awake.
Pseudoephedrine – Stimulates the Nervous System
Research shows that pseudoephedrine may lead to wakefulness by stimulating the central nervous system, activating the sympathetic nervous system, inducing alertness, and triggering the fight-or-flight response .
A clinical study found that sleep quality was affected among patients who were given 120 mg of pseudoephedrine for 2 weeks, and approximately 27% of patients complained of insomnia [5, 6].
Pseudoephedrine is also believed to affect the portion of the brain where the hypothalamus gland is situated.
This gland is recognized as the primary optimizer of the circadian rhythm.
Therefore, pseudoephedrine is sometimes prescribed to patients with symptoms of excessive daytime sleepiness, work shift syndrome, and narcolepsy .
Dextromethorphan – Induces Restlessness
Patients often complain that they tend to feel nervous and restless after taking dextromethorphan.
Some studies show that dextromethorphan can cause anxiety, jitteriness, sleeplessness, and insomnia [1, 19].
In a cohort study conducted among 100 participants in 2004, insomnia was a frequently reported side effect in participants who were administered dextromethorphan .
Guaifenesin – May Cause Wakefulness (More Research Needed)
There is some anecdotal evidence that suggests that some individuals prefer not to consume guaifenesin close to bedtime because it makes it harder for them to sleep .
However, there are limited studies that clearly elucidate the link between insomnia and the use of guaifenesin.
Extensive research is required in order to gain a better understanding of how these drugs may affect the quality of sleep, and induce wakefulness.
6 Ways to Sleep Better While Taking Mucinex
Below are 6 strategies for sleeping better when taking Mucinex:
1: Take Mucinex in the Morning to Avoid Sleep Disturbance
To stop Mucinex from keeping you awake at night, it’s recommended that you take Mucinex in the morning so that the medicine is out of your system by bedtime and therefore any side effects will not impact your sleep schedule.
Mixed findings have been reported in the scientific literature regarding sleep disturbances associated with the use of Mucinex.
One study found that some participants experienced restless leg syndrome as a result of taking Mucinex, but other research did not find any significant association between Mucinex consumption and sleep quality [8, 9].
Based on these contrasting results, it is hypothesized that medications such as Mucinex can interfere with sleep in more than one way.
For instance, Mucinex may cause a spike in blood pressure and heart rate, which can negatively influence your sleep schedule .
Therefore, it is necessary to assess the effects of Mucinex on the patient’s hemodynamic status, and then make appropriate changes to the daily medication plan, to prevent sleep disturbances.
I recommend that you consult your health care provider for a detailed medical evaluation and further assistance.
Nevertheless, if you are experiencing trouble sleeping at night while consuming Mucinex, I would suggest you try to avoid taking Mucinex late in the evening, in order to prevent its effects on your sleep.
2: Limit the Consumption of Stimulants While Taking Mucinex
To avoid insomnia while taking Mucinex, you should avoid consuming any products that are known to stimulate the central nervous system – such as those containing caffeine, tobacco, or alcohol.
More details are listed below:
Many researchers have found that even mild to moderate amounts of caffeine consumed during the evening hours can interfere with your sleep cycle .
I generally ask my patients to educate themselves regarding their dietary intake and be careful about the amount of hidden caffeine content in regular beverages.
- 250 milliliters of a soft drink usually contains about 20 to 30 milligrams of caffeine.
- 250 milliliters of green or black tea generally contains 50 to 80 milligrams of caffeine.
- 250 milliliters of an energy drink contain up to as much as 350 milligrams of caffeine.
If you have difficulties sleeping while taking Mucinex, I would strongly advise that you cut down on your consumption of caffeinated beverages at least four hours prior to your bedtime.
If your body is oversensitive to caffeine, I would suggest you avoid taking any caffeine-containing drink for at least eight hours before your bedtime.
Studies have found that nicotine released from tobacco-containing products – such as chewing tobacco, cigars, cigarettes, and vape fluid – can substantially interfere with sleep, increase the probability of daytime sleepiness, and cause wakefulness at night .
In addition to that, it is well known that smoking is one of the main risk factors for certain respiratory disorders, which can further worsen your quality of sleep.
Therefore, I cannot emphasize enough the importance of abstaining from tobacco-containing products prior to bedtime or avoiding them altogether (especially when your pulmonary system is infected), and your physician has prescribed you an expectorant, such as Mucinex.
Studies aimed at investigating the effects of alcohol on sleep have found that drinking alcohol on a regular basis may initially induce sleep, but later during the night, it can suppress a critical element of sound sleep – rapid eye movement (REM) .
Other research has found that consuming alcohol in the evening hours can weaken the regulation of melatonin, which is the principal sleep-regulating hormone .
In addition to that, drinking alcohol and taking Mucinex together can not only delay the recovery process but can also result in unwanted adverse effects, because alcohol may interfere with the metabolizing of Mucinex.
Therefore, I would advise you to avoid the consumption of alcoholic beverages while taking Mucinex in order to improve the quality of your sleep and prevent unwanted hepato-toxic reactions.
3: Avoid Fatty Meals that Interfere With Mucinex Metabolization
I would strongly recommend that you avoid consuming your meals late at night so that you can develop a healthy sleeping schedule.
Eating heavy, greasy meals late in the evening can interfere with the circadian rhythm, and induce symptoms of sleep disorders, such as obstructive sleep apnea .
Furthermore, studies have shown that overindulging in fattier meals and eating larger meals at dinnertime can also negatively affect the metabolizing of Mucinex, resulting in indigestion and sleeplessness .
To prevent this, I would suggest you eat your dinner at least three hours prior to your bedtime, so that you will have sufficient time to digest your meal.
It would be best if you can adequately space out the timings of your meals and medications, as advised by your doctor.
I would also advise you not to drink lots of fluids closer to your bedtime, in order to prevent the urge to urinate during the night.
I would recommend that you opt for healthier food options in general – try to eat meals containing organic whole grains, fresh fruits and vegetables, fish, poultry, meat, eggs, and dairy in small portions throughout the day.
These healthy food products contain vital vitamins and minerals that may help you to optimize your melatonin levels, and enhance the quality of your sleep.
4: Exercise Regularly to Optimize the Quality of Your Sleep
It is a well-known fact that routine exercise can improve the quality and duration of sleep .
However, it is very important to understand how the timing, intensity, and duration of your exercise regimen can influence your sleeping pattern.
In my opinion, if you have difficulty sleeping while taking Mucinex, you must refrain from over-training your body, and engaging in high-intensity training sessions.
I would suggest you schedule your workouts either earlier on in the day, or at least no sooner than 3 hours before bedtime.
I would also encourage habits of mindfulness, such as practicing gentle yoga asanas, light stretching, and daily meditation prior to sleeping.
A few studies have demonstrated that yoga and meditation practices done on a regular basis can significantly improve sleep quality and alleviate the symptoms of insomnia [17, 18].
5: Avoid Medications That Interact With Mucinex
Side effects associated with the use of Mucinex, such as dry mouth, headache, nausea, upset stomach, loss of appetite, and vomiting are rare.
However, if these side effects persist, or worsen over time, it is recommended that you promptly consult your physician .
In addition to being cautious of the side effects of Mucinex, it is important to know that some medications may interfere with the metabolic pathway of Mucinex.
This could negatively influence the efficiency of Mucinex, prolong the duration of its action, augment adverse reactions, or deteriorate the medicine’s own effectiveness when taken along with Mucinex.
Some drugs can also potentially enhance the effectiveness, minimize side effects, or even supplement their course of action, when taken along with Mucinex.
Thus, it is strongly recommended that you consult your physician before making any alterations to a prescription, in order to avoid unnecessary drug interactions.
A few products and medications that are known to potentially interact with Mucinex are listed as follows:
- Caffeine, alcohol, or nicotine containing products.
- Dietary drugs such as phentermine.
- Antidepressant medicines, such as imipramine and amitriptyline.
- Monoamine oxidase inhibitors, such as phenelzine, rasagiline, selegiline, and isocarboxazid.
- Anti-hypertensive medications.
- Neuronal stimulants, such as methylphenidate.
Please note that the aforementioned list is not exhaustive, and it only includes the most commonly used medications which may potentially interact with Mucinex.
I advise you to refer to your physician with your detailed medical history, a current list of medications, and a list of complaints or symptoms for accurate diagnosis, suitable prescription, and a better overall treatment plan.
6: Do Not Exceed the Recommended Mucinex Dose
It is important that you take Mucinex in the right way, as prescribed by your doctor or pharmacist.
It is necessary to be careful regarding the dosage of Mucinex.
I do not recommend that you take more than four tablets in a day, and if you are using a liquid formulation, you must make sure to accurately measure the dosage.
I advise you not to give Mucinex to your children, especially if they are under the age of twelve years – unless prescribed by their pediatrician.
It is crucial that your doctor is well aware of your medication regimen, and that you do not take any additional cough suppressive medicines without their knowledge.
If you are pregnant, breastfeeding, using oral contraceptive pills, or if you have been diagnosed with any of the illnesses listed below, I suggest that you have a discussion with your doctor.
Disclose your condition in all honesty, and ask them if taking Mucinex is safe for you.
- High blood pressure.
- Heart disease.
- Coronary artery disease.
- Blood circulation problems.
- Thyroid problems.
- Enlarged prostate gland.
- Urinary diseases.
- Sleep-related problems.
I would also advise you not to drive any vehicles, or perform any heavy-duty tasks until you know how Mucinex affects your body.
For some individuals, Mucinex may weaken their motor reactions and negatively impact their ability to stay alert.
If you miss a dose of Mucinex, I suggest you take it as soon as possible, but if it is almost time for your next dose, then you should skip the missed dose, and continue following your regular dosing schedule.
It is important to make sure that you are not double-dosing.
I urge you to seek medical help immediately if you notice any allergic or adverse reactions to Mucinex, and alert your physician at the earliest possible moment, if your symptoms get worse, or persist for more than a week.
Conclusion: Take Mucinex in the Morning
Mucinex is commonly indicated to relieve nasal and thoracic congestion, and it is readily available over the counter under the brand names Mucinex (guaifenesin), Mucinex D (guaifenesin/ pseudoephedrine), and Mucinex DM (guaifenesin/ dextromethorphan).
Although additional research is needed to understand the effects of Mucinex in its entirety, some evidence from scientific literature suggests that Mucinex may potentially interfere with the sleep/wake cycle and circadian rhythm – resulting in sleep disturbances, such as poor sleep quality and insomnia.
In order to obtain better sleep while taking Mucinex, it is recommended that you avoid taking Mucinex during late evening hours, limit your consumption of nervous system stimulants – such as caffeine, tobacco, and alcohol – maintain a healthy dietary intake, and be mindful of the timing of your meals.
You should also exercise on a regular basis, but avoid over-training your body while recovering.
Try to include mindfulness-based practices, such as yoga and meditation, in your nighttime routine.
You should always consume Mucinex in the right way, as prescribed by your doctor or pharmacist, and consult your doctor prior to making any changes to your prescription, or if you experience persistent or worsening side-effects of Mucinex.
By taking the aforementioned points into consideration while consuming Mucinex, you can optimize the quality of your sleep, achieve a restful and healthy night’s sleep, and recover quickly from your nasal or chest congestion.
Sources and References
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 Albrecht HH, Dicpinigaitis PV, Guenin EP. Role of guaifenesin in the management of chronic bronchitis and upper respiratory tract infections. Multidiscip Respir Med. 2017;12:31. Published 2017 Dec 11. doi:10.1186/s40248-017-0113-4
 Gelotte CK, Albrecht HH, Hynson J, Gallagher V. A Multicenter, Randomized, Placebo-Controlled Study of Pseudoephedrine for the Temporary Relief of Nasal Congestion in Children With the Common Cold. J Clin Pharmacol. 2019;59(12):1573-1583. doi:10.1002/jcph.1472
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 Lopes TDVC, Borba ME, Lopes RDVC, et al. Eating Late Negatively Affects Sleep Pattern and Apnea Severity in Individuals With Sleep Apnea. J Clin Sleep Med. 2019;15(3):383-392. Published 2019 Mar 15. doi:10.5664/jcsm.7658
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Main image: ‘Woman is sleeping in the bedroom’ – by choreograph (used with permission and commercially licensed through Envato Elements).
Dan is the founder and head content creator at Bedroom Style Reviews.
He has been working as a professional online product reviewer since 2015 and was inspired to start this website when he ended up sleeping on a memory foam mattress that was too soft and gave him backache.
Through in-depth research and analysis, Dan’s goal with this website is to help others avoid such pitfalls by creating the best online resource for helping you find your ideal mattress, bedding, and bedroom furniture.
Dan is a qualified NVQ Level 2 Fitness Instructor with 6 years’ experience helping clients improve their health through diet, exercise, and proper sleep hygiene.
He also holds several college and university-level qualifications in health sciences, psychology, mathematics, art, and digital media creation – which helps him to publish well researched and informative product reviews as well as articles on sleep, health, wellbeing, and home decor.
Dan also has direct personal experience with insomnia, anxiety, misophonia (hypersensitivity to sounds), and pain from both acute and long-standing sporting injuries – he enjoys writing insightful articles around these subjects to help fellow sufferers of such conditions.
Learn more about Dan here.