| adrenergic agents | Drugs that act on adrenergic receptors or affect the life cycle of adrenergic transmitters. Included here are adrenergic agonists and antagonists and agents that affect the synthesis, storage, uptake, metabolism, or release of adrenergic transmitters. (12 Dec 1998) |
|---|---|
| alkylating agents | Highly reactive chemicals that introduce alkyl radicals into biologically active molecules and thereby prevent their proper functioning. Many are used as antineoplastic agent, but most are very toxic, with carcinogenic, mutagenic, teratogenic, and immunosuppressant actions. They have also been used as components in poison gases. (12 Dec 1998) |
| anti-allergic agents | Agents that are used to treat allergic reactions. most of these drugs act by preventing the release of inflammatory mediators or inhibiting the actions of released mediators on their target cells. (12 Dec 1998) |
| anti-allergic and respiratory system agents | A collective term for drugs used to treat allergic reactions as well as those drugs that produce an effect on the respiratory system. (12 Dec 1998) |
| anti-anxiety agents | Agents that alleviate anxiety, tension, and neurotic symptoms, promote sedation, and have a calming effect without affecting clarity of consciousness or neurologic conditions. Some are also effective as anticonvulsants, muscle relaxants, or anaesthesia adjuvants. Adrenergic beta-antagonists are commonly used in the symptomatic treatment of anxiety but are not included here. Substances with a benzodiazepine ring structure widely used to treat anxiety and neuroses. Drugs in this class also generally have sedative or weak hypnotic properties and may be effective as muscle relaxants, anticonvulsants, and anaesthesia adjuvants. (12 Dec 1998) |
| anti-arrhythmia agents | Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibres. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade. (12 Dec 1998) |
| anti-asthmatic agents | Drugs that are used to treat asthma. (12 Dec 1998) |
| anticarcinogenic agents | Agents that reduce the frequency or rate of spontaneous or induced tumours independently of the mechanism involved. They differ from antineoplastic agent in that they prevent neoplasms from forming. The anticarcinogenic substances can be divided into three categories. The first consists of compounds that prevent the formation of carcinogens from precursor substances. The second group consists of "blocking agents" which inhibit carcinogenesis by preventing carcinogenic agents from reaching or reacting with critical target sites in the tissues. The third group is the "suppressor agents" which act by suppression of expression of neoplasia in cells previously exposed to carcinogens that would otherwise cause neoplasms. (12 Dec 1998) |
| anticestodal agents | Agents used to treat tapeworm infestations in man or animals. (12 Dec 1998) |
| anticholesteraemic agents | Substances that promote a reduction of blood cholesterol levels. (12 Dec 1998) |
| anti-coagulant agents | Medications, like heparin, used as blood-thinners to prevent blood clots and to maintain open blood vesssels. (12 Dec 1998) |
| antidepressive agents | Mood-stimulating drugs used primarily in the treatment of affective disorders and related conditions. Several monoamine oxidase inhibitors are useful as antidepressants apparently as a long-term consequence of their modulation of catecholamine levels. The tricyclic compounds useful as antidepressive agents (antidepressive agents, tricyclic) also appear to act through brain catecholamine systems. A third group (antidepressive agents, second-generation) is a diverse group of drugs including some that act specifically on serotonergic systems. (12 Dec 1998) |
| antidepressive agents, second-generation | A structurally and mechanistically diverse group of drugs that are not tricyclics or monoamine oxidase inhibitors. The most clinically important appear to act selectively on serotonergic systems, especially by inhibiting serotonin reuptake. (12 Dec 1998) |
| antidepressive agents, tricyclic | Substances that contain a fused three-ring moiety and are used in the treatment of depression. These drugs block the uptake of norepinephrine and serotonin into axon terminals and may block some subtypes of serotonin, adrenergic, and histamine receptors. However the mechanism of their antidepressant effects is not clear because the therapeutic effects usually take weeks to develop and may reflect compensatory changes in the central nervous system. (12 Dec 1998) |
| anti-dyskinesia agents | Drugs used in the treatment of movement disorders. most of these act centrally on dopaminergic or cholinergic systems. Among the most important clinically are those used for the treatment of parkinson disease (antiparkinson agents) and those for the tardive dyskinesias. (12 Dec 1998) |