Methadrine is a brand name for ephedrine, a medication used primarily as a stimulant and decongestant. This medication can be found under a variety of names depending on the country, including Pseudophedrine, Sudafed, and Bronkaid. While ephedrine is often used to treat asthma and other breathing conditions, it is also a common ingredient in some weight loss supplements and performance enhancers. Ephedrine works by stimulating the central nervous system and increasing heart rate, which can boost alertness, focus, and athletic performance. However, it can also have dangerous side effects, including high blood pressure, heart palpitations, and strokes. As such, it is important to use this medication only under a doctor's guidance.