"Phenergan with dextromethorphan is the brand name for the compound that includes promethazine, an antihistamine, and dextromethorphan, a cough-suppressant, which was approved by the FDA in 1957. Promethazine with dextromethorphan is available with a prescription, both as a generic drug and under the brand name Phenergan with Dextromethorphan. Promethazine with dextromethorphan is an antihistamine with anti-tussive, or cough suppressing, properties. Here's how promethazine works: During an allergic reaction, the body releases histamine, a protein that binds to cell receptors and leads to sneezing, itching, and increased mucus production. When promethazine enters the body, it joins with these cell receptors, blocking the histamine from binding and ending the reaction. Dextromethorphan is an over-the-counter cough suppressant, and when it is combined with promethazine, the compound treats coughing better than either medication individually. The compound is used to ease symptoms of the common cold and various allergic reactions. Phenergan with dextromethorphan is available in syrup form. Dosages vary greatly depending on your need.Because promethazine can be addictive, never take extra doses of this medication. The most common side effects of promethazine with dextromethorphan include drowsiness, blurred vision, increased sensitivity to sunlight, headaches and appetite loss, but you should ask your doctor for a complete list. Also, be sure to tell your doctor immediately if you experience confusion, a rapid pulse, skin rash, or any other significant changes. Promethazine with dextrometherphan should not be taken in conjunction with sedatives or MAO inhibitors. Be careful about taking other medications containing dextromethorphan, as an overdose can occur. Ask your doctor for a full list of medications and conditions that should not be combined with this compound. Phenergan with Dextromethorphan can be extremely helpful for people who suffer from coughing associated with colds and allergic reaction. However, the medication should always be used under the direct care of a physician. Please ask for and review all of the information provided by your doctor before taking this medication. The information in this video is intended to supplement, not substitute for, the expertise of your physician. Always consult your doctor before using this drug.