antihistamine. a drug that counteracts the effects of histamine, a normal body chemical that among its actions is believed to cause the symptoms of persons who are hypersensitive to various allergens.hile the term antihistamine can broadly include any agent that blocks any histamine receptor, in practice it is usually used to denote those blocking the H 1 type of receptors (H1 receptor antagonists), those involved in allergic reactions.
The Executive Branch. From the President, to the Vice President, to the Cabinet, learn more about the Executive Branch of the government of the United States. The power of the Executive Branch is vested in the President of the United States, who also acts as head of state and Commander-in-Chief of the armed forces. The President is responsible for implementing and enforcing the laws written by Congress and, to that end, appoints the heads of the federal agencies, including the Cabinet.
The White House Office is an entity within the Executive Office of the President of the United States. The White House Office is headed by the White House Chief of Staff, who is also the head of the Executive Office.The staff of the various offices are based in the West Wing and East Wing of the White House, the Eisenhower Executive Office Building, and the New Executive Office Building.he White House Office is organized in accordance with the wishes of each incumbent President and is directed by staff chosen by the President. A staff authorization was initially established in 1978 (92 Stat. 2445).