"Phenergan is the brand name for promethazine, an antihistamine and nausea inhibitor approved by the FDA in 1951. Promethazine is available with a prescription, both as a generic drug and under the brand name Phenergan. Promethazine is an antihistamine with sedative and anti-emetic, or anti-nausea, 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. Promethazine is used to relieve symptoms of various allergic conditions, like seasonal hay fever. It is also frequently prescribed to prevent and treat nausea and motion sickness. Phenergan is available orally in tablets and in a syrup form, and as a rectal suppository. Dosages range from twelve point five to fifty milligrams.Because promethazine can be addictive, always take the medication exactly as prescribed. The most common side effects of promethazine include drowsiness, blurred vision and increased sensitivity to sunlight, but you should ask your doctor for a complete list.Also, be sure to tell your physician immediately if you experience confusion, involuntary tics, yellow skin or any other significant changes. Promethazine should not be taken in conjunction with sedatives, MAO inhibitors. Ask your doctor for a full list of medications and conditions that should not be combined with promethazine. Phenergan can be extremely helpful for people who suffer from allergic reactions or nausea. 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."