Acetaminophen is a pain reliever and fever reducer. Dextromethorphan is a cough suppressant. Phenylephrine is a decongestant. Triprolidine is an antihistamine.

Mucinex Nightshift Sinus is a combination medicine used to treat headache, fever, body aches, cough, sore throat, runny or stuffy nose, sneezing, or sinus pressure caused by the flu or common cold.

Mucinex Nightshift Sinus may also be used for purposes not listed in this medication guide.

Do not use this medicine if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

An acetaminophen overdose can damage your liver or cause death. Call your doctor at once if you have stomach pain (upper right side), loss of appetite, tiredness, itching, dark urine, clay-colored stools, or yellowing of your skin or eyes.

Stop taking this medicine and call your doctor right away if you have skin redness or a rash that spreads and causes blistering and peeling.

Do not use this medicine only to make a child sleepy.

Use exactly as directed on the label, or as prescribed by your doctor. An acetaminophen overdose can damage your liver or cause death. Cold or cough medicine is only for short-term use until your symptoms clear up.

Always follow directions on the medicine label about giving cough or cold medicine to a child. Do not use the medicine only to make a child sleepy. Death can occur from the misuse of cough or cold medicines in very young children.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Call your doctor if you have a sore throat for more than 2 days, especially if you also have fever, headache, rash, nausea, or vomiting.

If you need surgery or medical tests, tell the surgeon or doctor if you have taken this medicine within the past few days.

Store at room temperature away from moisture and heat. Do not allow liquid medicine to freeze.

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

You should not use this medicine if you are allergic to acetaminophen, dextromethorphan, phenylephrine, or triprolidine.

Ask a doctor or pharmacist if this medicine is safe to use if you have:

• liver disease, cirrhosis, alcoholism, or more than 3 alcoholic beverages per day;

• heart problems, high blood pressure;

• diabetes;

• glaucoma;

• a condition for which you take warfarin (Coumadin, Jantoven);

• an enlarged prostate or urination problems;

• a thyroid disorder;

• breathing problems; or

• cough with mucus, or cough caused by smoking, asthma, or emphysema.

Ask a doctor before using this medicine if you are pregnant or breastfeeding.

Since Mucinex Nightshift Sinus is used when needed, you may not be on a dosing schedule. Skip any missed dose if it's almost time for your next dose. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of acetaminophen can damage your liver or cause death.

Early signs of acetaminophen overdose include loss of appetite, nausea, vomiting, sweating, or weakness. Later symptoms may include upper stomach pain, dark urine, and yellowing of your skin or eyes.

Avoid drinking alcohol. It may increase your risk of liver damage.

Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired.

Ask a doctor or pharmacist before using any other medicine that may contain acetaminophen (sometimes abbreviated as APAP). Taking too much acetaminophen can lead to a fatal overdose.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

In rare cases, acetaminophen may cause a severe skin reaction that can be fatal. This could occur even if you have taken acetaminophen in the past and had no reaction. Stop taking this medicine and call your doctor right away if you have skin redness or a rash that spreads and causes blistering and peeling. If you have this type of reaction, you should never again take any medicine that contains acetaminophen.

This medicine may cause serious side effects. Stop using this medicine and call your doctor at once if you have:

• any new or worsening symptoms;

• nervousness, dizziness, or drowsiness;

• fever for longer than 3 days;

• redness, swelling, or rash;

• ongoing headache; or

• pain, cough, or sinus congestion lasting more than 7 days.

Some side effects may be more likely in older adults.

Common side effects of Mucinex Nightshift Sinus may include:

• dizziness, drowsiness;

• dry mouth, nose, or throat;

• blurred vision;

• constipation;

• feeling restless or excited (especially in children); or

• sleep problems (insomnia).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Avoid using this medicine with other drugs that cause drowsiness or slow your breathing (such as opioid medicine, a muscle relaxer, or medicine for anxiety or seizures). Ask a doctor or pharmacist before using any other medication, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed in this medication guide.