Final answer:
Corticosteroids are the drugs that block the immune system from causing lung inflammation, used to treat asthma and COPD by downregulating the inflammatory response.
Step-by-step explanation:
The drugs that block the immune system from causing inflammation in the lung and are used to treat asthma and COPD are corticosteroids. These drugs are anti-inflammatory and work by downregulating the inflammatory response in the body. Corticosteroids can be administered in various forms such as inhalers for asthma to reduce airway inflammation, or orally and intravenously for more systemic conditions like severe allergies or autoimmune diseases. It's important to use these medications under the guidance of a healthcare professional, as long-term use of corticosteroids can lead to undesirable consequences such as increased susceptibility to infection due to their immunosuppressive effects.