Patented medicine can also be referred to as proprietary medicine, branded drugs, trademarked drugs or exclusive medicines. These terms describe medications that are protected by intellectual property rights, allowing the pharmaceutical company that developed them to have exclusive rights to manufacture and sell them for a certain period of time. Proprietary drugs are often more expensive than generics, as the cost of research and development is factored into the pricing. Despite this, proprietary drugs are often preferred by physicians due to the research and clinical trials that back up their safety and efficacy. Synonyms for patented medicine may be used interchangeably depending on region, industry or company preference.