The brand name of a drug. As long as a pharmaceutical company holds a patent on a drug, it alone will produce and sell that drug, which will have a brand name in addition to its generic (established) name. The generic name is associated with the class of medicine and the chemical composition of the drug. The brand name belongs to a specific company and can be used only by that company as part of a promotional or marketing strategy for the drug.
The trade name of a drug: the name assigned to it by the firm that manufactured it. For example. Mogadon is the proprietary name for nitrazepam.
The trade name of a drug registered by the pharmaceutical company which has developed and patented it. This protects the name, ingredients and manufacturing technique for a set period of time, and helps the company to recoup the often costly research and development needed to produce and test the drug. Doctors may prescribe a drug by its trade name or by its official, approved name, although the NHS encourages the latter.