The term "necessary drugs" refers to medications that are essential for treating certain health conditions and maintaining good health. These drugs are considered necessary because they provide significant therapeutic benefits, and their absence could result in severe or life-threatening consequences. They may be used to treat chronic illnesses such as diabetes, hypertension, asthma, or other conditions that require ongoing management with medication. The term is often used interchangeably with "essential drugs" which refers specifically to those medications that are considered necessary for basic healthcare systems and should be available to all citizens regardless of their ability to pay.