Can you take Mucinex and DayQuil together

Mixing Mucinex and DayQuil together

Mucinex is a Brand name for a medication containing guaifenesin as an active ingredient that is used as expectorant for relieving the symptoms of cough and mucus in the chest due to flu, colds or hay fever. This drug reduces congestion in chest and makes coughs more productive by thinning mucus in the lungs and making it less sticky and easier to cough up. For regular (short-acting) oral dosage forms usual doses are 100-400mg 3-4 times a day, and for extended-release dosage forms usual doses are 600 to 1200 mg two times a day. Mucinex works best when it is taken with plenty of water.

Other Brand names for preparations containing guaifenesin are: Bidex 400, Organidin NR, Antitussin, Guaifenex, Robitussin, Allfen, Altarussin and Amibid LA.

DayQuil is a brand name for OTC medication which is used for relieving symptoms of common cold and flu. There are several formulations of DayQuil on the market: DayQuil Cough
(liquid dosage form containing dextromethorphan 15mg), DayQuil Cold & Flu (liquid and liquicaps containing dextromethorphan 10mg, acetaminophen 325 mg and phenylephrine 5 mg), DayQuil Severe Cold & Flu (liquid and caplets containing acetaminophen 325 mg, dextromethorphan 10 mg, guaifenesin 200 mg and phenylephrine 5 mg), DayQuil Mucus Control DM (liquid containing dextromethorphan 10 mg and guaifenesin 200 mg) and Dayquil Sinex (liquicaps containing acetaminophen 325 mg and phenylephrine 5 mg and nasal spray containing oxymetazoline HCl 0.05%)

Other Brand names on the market containing similar combination are: NyQuil, Alka-Seltzer Plus Day Cold, Theraflu, Tylenol Alka-Seltzer Plus Day Sinus Congestion, Allergy & Cough, Alka-Seltzer Plus Severe Sinus Congestion & Cough and others.

How does Mucinex and DayQuil work in the body

Guaifenesin acts by reducing the viscosity and increasing the volume of secretions in the trachea and bronchi. By reducing the adhesiveness and viscosity of secretions, guaifenesin increases the mucociliary mechanism efficacy in removing secretions which has been accumulated in the upper and lower airways. Studies have also shown that guaifenesin has muscle relaxant and anticonvulsant properties due to antagonism effects on NMDA receptors.

Pseudoephedrine is sympathomimetic amine with direct action on the adrenergic receptor system. The vasoconstriction is produced after α-adrenergic receptors activation that are located on the muscles lining of the walls of blood vessels. The constricted blood vessels allow less fluid to leave the blood vessels and enter the nose, throat and sinuses, so results are: decreased inflammation of nasal membranes and decreased mucus production. In bronchi, due to β2-adrenergic receptors activation, this substance can produce relaxation of smooth muscle, causing bronchial dilation and decreasing congestion and breathing difficulties.

Acetaminophen is highly selective COX-2 inhibitor that inhibits prostaglandin synthesis. It can inhibit COX-2 in CNS. Acetaminophen also acts on the hypothalamic heat regulating centers to produce antipyresis.

Dextromethorphan acts on cough center in medulla by decreasing sensitivity of cough receptors and by interrupting impulse transmission.

Phenylephrine is sympathomimetic with direct action on the adrenergic receptor system. The vasoconstriction is produced after α-adrenergic receptors activation.

Can patients take Mucinex and DayQuil together

Patients must talk with their doctors or pharmacists first before they take some of Mucinex or DayQuil product together. Some Mucinex and DayQuil formulations can contain the same active ingredient or active ingredients with same effects. For example Mucinex DM and DayQuil Cold & Flu, both contain the same active ingredient-dextromethorphan, or Mucinex D (contain pseudoephedrine) and DayQuil Cold & Flu (contain phenylephrine), both contain active ingredients with same effects (they are both sympathomimetics). Hence, patients could double the doses of the same drug or drug effects will become additive if they take these products at the same time.  This is why patients should always look at the PIL (Patient Information Leaflet) and talk with their doctors or pharmacists first, before they combine these two medications.

By mixing Mucinex and DayQuil products that contain dextromethorphan, there is a higher risk of side dextromethorphan’s effects to occur. High amounts of dextrometorphan can shut down the central nervous system. Typical side effects are: impaired vision, sweating and fever, rapid breathing, nausea, vomiting and diarrhea, slurred speech, impaired judgment and mental function and rapid eye movement.

Some of the Mucinex products already contain vasoconstrictor – pseudoephedrine like Mucinex D, or Mucinex D Max Strength and the same goes for DayQuil products such as DayQuil Cold & Flu and Dayquil Sinex that contain phenylephrine as vasoconstrictor. By mixing these products together patients may get too much of the drugs with same effects and there is a high probability of side effects to occur.

Patients with heart or blood pressure issues should always talk with their doctors first before taking these drugs together! In these patients, pseudoephedrine’s and phenylephrine’s sympathomimetic effects on the heart and blood vessels can make their symptoms far worse. Patient should look for medical help if they experience some of the following symptoms: fast, irregular, pounding heartbeat, mental or mood changes like anxiety, confusion, restlessness, shaking, difficulty urinating, as well as swelling, and difficulty breathing.

The table below shows side effects after Mucinex and DayQuil administration in recommendable doses. The incidence of side effects can be significantly increased if these drugs are overdosed.


Side effects

Frequency Not Defined Hypertension, Tachycardia, Hypotension, Reflex tachycardia, Severe peripheral and visceral vasoconstriction, Tremor, Dizziness, Excitability, Headache, Sedation, Sleepiness, Restlessness, Dermatologic rash, Increased appetite, Xerostomia, Anemia blood dyscrasias (neutropenia, pancytopenia, leukopenia), Bilirubin and alkaline phosphatase may increase, Urinary retentionRash, Itching, Hives.

Special precautions and warnings during Mucinex and DayQuil administration:

  • Patients shouldn’t use these medicines if they have used MAO inhibitors drugs such as furazolidone (Furoxone), phenelzine (Nardil), isocarboxazid (Marplan), selegiline (Eldepryl, Emsam, Zelapar), rasagiline (Azilect), or tranylcypromine (Parnate) in the last 14 days. Drug interactions can occur, leading to serious side effects.
  • Patients should ask their doctor or pharmacist before using these products if they have: high blood pressure, some heart disease, diabetes or a thyroid disorder.
  • Pregnant patients shouldn’t use these medications without medical advice. It is not known whether these drugs will harm an unborn baby. These medicines should not be used if mother is breast-feeding a baby.
  • Patients should also limit alcoholic beverages while using these drugs.
  • This drug can make patients dizzy or drowsy. They should not drive, use machinery, or do any activity that requires alertness.
  • Patients should avoid these medications if they also take caffeine pills, diet pills, or other stimulants. Taking decongestants (pseudoefedrine, phenylephrine) together with stimulants can increase the risk of unpleasant side effects.
  • Medicines such as sedatives, sleeping pills, narcotic pain medicines, medicine for seizures, anxiety or depression, and muscle relaxers can add sedation and sleepiness that can be also caused by dextromethorphan, phenylephrine and pseudoephedrine.
  • Children and elderly may be more sensitive to the side effects of these drugs.
  • Patients with phenylketonuria should avoid these medicines.
  • Children younger than 4 years should also avoid these medicines. These medicines shouldn’t be taken for longer than 7 days in a row

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