Canadian Medical Guide > Chemicals and Drugs > Neurotransmitters and Neurotransmitter Agents > Neurotransmitter Agents > Histamine Agents > Histamine Antagonists Terms and Definitions




Histamine Antagonists

Medical Definition: Drugs that bind to but do not activate histamine receptors, thereby blocking the actions of histamine or histamine agonists. Classical antihistaminics block the histamine H1 receptors only.
Guide Notes: GEN or unspecified; prefer specifics; do not confuse with HISTAMINE AGONISTS; DF: HISTAMINE ANTAG
Previously Indexed: Histamine H1 Receptor Blockaders (1966-1976)
Histamine Antagonists Categories.
Canadian Medical Guide Definition Histamine H1 Antagonists - Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.
Canadian Medical Guide Definition Histamine H2 Antagonists - Drugs that selectively bind to but do not activate histamine H2 receptors, thereby blocking the actions of histamine. Their clinically most important action is the inhibition of acid secretion in the treatment of gastrointestinal ulcers. Smooth muscle may also be affected. Some drugs in this class have strong effects in the central nervous system, but these actions are not well understood.

Histamine Antagonists Medical Definitions and Terms

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