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.
History US Government. The leader of the Executive Branch is the President of the United States. The President holds all the power for this branch of the government and the other members report to the President.Other parts of the Executive branch include the Vice President, the Executive Office of the President, and the Cabinet.The President. The President is seen as the leader of the US Government and is both the head of state and the Commander-in-Chief of the US armed forces.istory US Government. The leader of the Executive Branch is the President of the United States. The President holds all the power for this branch of the government and the other members report to the President.