| androgen antagonists | Compounds which inhibit or antagonise the biosynthesis or actions of androgens. (12 Dec 1998) |
|---|---|
| gaba antagonists | Drugs that bind to but do not activate gaba receptors, thereby blocking the actions of endogenous gaba or gaba agonists. (12 Dec 1998) |
| cholinergic antagonists | Drugs that bind to but do not activate cholinergic receptors, thereby blocking the actions of acetylcholine or cholinergic agonists. (12 Dec 1998) |
| muscarinic antagonists | Drugs that bind to but do not activate muscarinic cholinergic receptors (receptors, muscarinic), thereby blocking the actions of endogenous acetycholine or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system. Antagonists that discriminate among the various muscarinic receptor subtypes and might allow better control of peripheral and central actions are under development. (12 Dec 1998) |
| heparin antagonists | Coagulant substances inhibiting the anticoagulant action of heparin. (12 Dec 1998) |
| prostaglandin antagonists | Compounds that inhibit the action of prostaglandins. (12 Dec 1998) |
| histamine antagonists | Drugs that bind to but do not activate histamine receptors, thereby blocking the actions of histamine or histamine agonist. Classical antihistaminics block the histamine h1 receptors only. (12 Dec 1998) |
| 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 antagonise 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. (12 Dec 1998) |
| 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. (12 Dec 1998) |
| hormone antagonists | Chemical substances which inhibit the function of the endocrine glands, the biosynthesis of their secreted hormones, or the action of hormones upon their specific sites. (12 Dec 1998) |
| hormones, hormone substitutes, and hormone antagonists | A collective grouping for both naturally occurring and synthetic hormones, substitutes, and antagonists. (12 Dec 1998) |
| serotonin antagonists | Drugs that bind to but do not activate serotonin receptors, thereby blocking the actions of serotonin or serotonin agonists. (12 Dec 1998) |
| narcotic antagonists | Agents inhibiting the effect of narcotics on the central nervous system. (12 Dec 1998) |
| dopamine antagonists | Drugs that bind to but do not activate dopamine receptors, thereby blocking the actions of dopamine or exogenous agonists. Many drugs used in the treatment of psychotic disorders (antipsychotic agents) are dopamine antagonists, although their therapeutic effects may be due to long-term adjustments of the brain rather than to the acute effects of blocking dopamine receptors. Dopamine antagonists have been used for several other clinical purposes including as antiemetics, in the treatment of tourette syndrome, and for hiccup. (12 Dec 1998) |
| opioid antagonists | Agents such as naloxone and naltrexone which have high affinity for opiate receptors but do not activate these receptors. These drugs block the effects of exogenously administered opioids such as morphine, heroin, meperidine, and methadone, or of endogenously released endorphins and enkephalins. (05 Mar 2000) |