What is Mucinex Fast-Max Night Time Cold & Flu (acetaminophen, dextromethorphan, doxylamine, and phenylephrine)? Acetaminophen is a pain reliever and fever reducer. Dextromethorphan is a cough suppressant. It affects the cough reflex in the brain that triggers coughing. Doxylamine is an antihistamine that reduces the effects of natural chemical histamine in the body.
Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose. Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose). Acetaminophen, dextromethorphan, doxylamine, and phenylephrine is a combination medicine used to treat headache, fever, body aches, cough, runny nose, sneezing, itching, and watery eyes caused by allergies, the common cold, or the flu.