antagonist drug definition
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens agonist-mediated responses rather than provoking a biological response itself upon binding to a receptor.They are sometimes called blockers; examples include alpha blockers, beta blockers, and calcium channel blockers.ur understanding of the mechanism of drug-induced receptor activation and receptor theory and the biochemical definition of a receptor antagonist continues to evolve. The two-state model of receptor activation has given way to multistate models with intermediate conformational states. Antagonist: A substance that acts against and blocks an action. Antagonist is the opposite of agonist. Antagonists and agonists are key players in the chemistry of the human body and in pharmacology.ntagonist: A substance that acts against and blocks an action. Antagonist is the opposite of agonist. Antagonists and agonists are key players in the chemistry of the human body and in pharmacology. Agonist: A substance that acts like another substance and therefore stimulates an action. Agonist is the opposite of antagonist.Antagonists and agonists are key players in the chemistry of the human body and in pharmacology.gonist: A substance that acts like another substance and therefore stimulates an action. Agonist is the opposite of antagonist. antagonist-a drug that neutralizes or counteracts the effects of another drug. drug-a substance that is used as a medicine or narcotic. estrogen antagonist, tamoxifen-an antagonist for estrogen that is used in the treatment of breast cancer.narcotic antagonist-an antagonist used to counteract the effects of narcotics (especially to counteract the depression of respiration).strogen antagonist, tamoxifen-an antagonist for estrogen that is used in the treatment of breast cancer. narcotic antagonist-an antagonist used to counteract the effects of narcotics (especially to counteract the depression of respiration). the antagonism which blocks or reverses the effects of an agonist, provided that the antagonist is given at an appropriate dosage. The antagonism is completely reversible, and an increase in the biophasic concentration of the agonist will overcome the effect of the antagonist.drug antagonism.drug antagonists are drugs that compete for the available receptors. They may be noncompetitive and have no pharmacological effect of their own, or competitive in that they are capable of reversing or altering an effect already achieved.he antagonism is completely reversible, and an increase in the biophasic concentration of the agonist will overcome the effect of the antagonist. drug antagonism. drug antagonists are drugs that compete for the available receptors. antagonist. n. 1. an opponent or adversary, as in a contest, drama, sporting event, etc. 2. (Physiology) any muscle that opposes the action of another. Compare agonist 1. 3. (Pharmacology) a drug that counteracts the effects of another drug. Compare synergist 1.strogen antagonist, tamoxifen-an antagonist for estrogen that is used in the treatment of breast cancer. narcotic antagonist-an antagonist used to counteract the effects of narcotics (especially to counteract the depression of respiration). Definition of AGONIST. 1. : one that is engaged in a struggle. 2. [from antagonist] a: a muscle that is controlled by the action of an antagonist with which it is paired.ADVERTISEMENT.efinition of AGONIST. 1. : one that is engaged in a struggle. 2. [from antagonist] a: a muscle that is controlled by the action of an antagonist with which it is paired. ADVERTISEMENT. Drug Antagonism. Synonym(s): Drug Opposition. An interaction between two or more drugs that have opposite effects on the body. Drug antagonism may block or reduce the effectiveness of one or more of the drugs.See Related Term(s): Drug Synergism.rug Antagonism. Synonym(s): Drug Opposition. An interaction between two or more drugs that have opposite effects on the body. Drug antagonism may block or reduce the effectiveness of one or more of the drugs. See Related Term(s): Drug Synergism. antagonist: a compound that blocks or inhibits the action of a neurotransmitter. direct-acting antagonist (aka receptor blocker): binds to the same receptor population as an agonist but fails to activate the target receptors.competitive antagonist: competes with an agonist for the same receptor population.ntagonist: a compound that blocks or inhibits the action of a neurotransmitter. direct-acting antagonist (aka receptor blocker): binds to the same receptor population as an agonist but fails to activate the target receptors. The term antagonist was originally coined to describe different profiles of drug effects. The biochemical definition of a receptor antagonist was introduced by Ariens and Stephenson in the 1950s. The current accepted definition of receptor antagonist is based on the receptor occupancy model.ur understanding of the mechanism of drug-induced receptor activation and receptor theory and the biochemical definition of a receptor antagonist continues to evolve. The two-state model of receptor activation has given way to multistate models with intermediate conformational states.
A drug that neutralizes or counteracts the effects of another drug.