Pharmaceutical drugs are given several names:

• A research name based on its chemical make-up or manufacturer, e.g. FTC
• A generic name which is the chemical name of the medicine, e.g. emtricitabine
• A brand name which belongs to a particular company. A brand name starts with a capital letter and is generally written in italics, e.g. Emtriva.

This booklet lists the most common names a drug has at the start of a drug entry.

The company that develops a drug can patent it, which means they have exclusive rights to manufacture it for a period of time.

Once the patent expires, other companies can produce their own versions of the same drug. These are called generic drugs.

Generics have the same active ingredients as branded drugs, but they are usually cheaper because there are reduced research and development costs associated with them.

Where possible, the NHS prescribes generic medicines, because they are cheaper and they work just as well as branded drugs. You may receive generic drugs with different packaging or colours from time to time because your clinic may buy drugs from several manufacturers. All generic versions of a drug contain the same active ingredients and work in the same way.