Mucinex Fast-Max Cold & Flu Arctic Burst is a liquid medication that combines a cough suppressant, an expectorant, a pain reliever, and a fever reducer to help relieve the symptoms of a cold or the flu. The cough suppressant, dextromethorphan HBr, works by blocking the cough center in the brain. The expectorant, guaifenesin, works by thinning mucus so that it can be coughed up more easily. The pain reliever, acetaminophen, works by reducing pain and fever. The decongestant, phenylephrine HCl, works by narrowing blood vessels in the nose and sinuses to relieve congestion. Mucinex Fast-Max Cold & Flu Arctic Burst is available in a honey and berry flavor and is easy to take. It is recommended for adults and children 12 years of age Some of the common side effects of Mucinex Fast-Max Cold & Flu Arctic Burst include drowsiness, dizziness, and upset stomach. Do not take Mucinex Fast-Max Cold & Flu Arctic Burst if you are allergic to any of its ingredients. Do not take this medication if you are taking a MAO inhibitor, a type of antidepressant. Keep Mucinex Fast-Max Cold & Flu Arctic Burst out of reach of children. Store it at room temperature in a cool, dry place.