Antagonist Health Dictionary

These are drugs that block the action of HISTAMINE at the H2 receptor (which mediates the gastric and some of the cardiovascular effects of histamine). By reducing the production of acid by the stomach, these drugs – chie?y cimetidine, ranitidine, famotidine and nizatidine – are valuable in the treatment of peptic ulcers (healing when used in high dose; preventing relapse when used as maintenance therapy in reduced dose), re?ux oesophagitis (see OESOPHAGUS, DISEASES OF), and the ZOLLINGERELLISON SYNDROME. These drugs are now being supplanted by PROTON-PUMP INHIBITORS and HELICOBACTER PYLORI eradication therapy. (See also DUODENAL ULCER.)... h2 receptor antagonists

A group of drugs used in the treatment of hypertension (high blood pressure). They have a similar action to ACE inhibitors but do not cause a dry cough. Examples are losartan and valsartan.... angiotensin ii antagonists

See H-receptor antagonists.... histamine-receptor antagonists

A drug that blocks the action of a hormone.... hormone antagonist

A group of antiallergy drugs, such as montelukast and zafirlukast, used to prevent symptoms of mild to moderate asthma. The drugs work by blocking the effects of leukotrienes – naturally occurring substances released in the lungs during an allergic reaction.

Because they are not bronchodilator drugs, and will not relieve an existing attack, they are usually used with bronchodilators and inhaled corticosteroids to reduce the frequency of attacks.

Side effects include gastrointestinal disturbances and headache.

Skin and hypersensitivity reactions may also occur.... leukotriene receptor antagonists

A group of drugs used to treat the nausea and vomiting caused by radiotherapy and anticancer drugs. They are also used to control nausea and vomiting following surgery. Common serotonin antagonists include granisetron and ondansetron.... serotonin antagonists

any one of a class of drugs that block the action of the hormone *angiotensin II, which constricts blood vessels; they are therefore useful in treating *hypertension. These drugs include candesartan, irbesartan, losartan, telmisartan, and valsartan. Side-effects are usually mild.... angiotensin ii antagonist

one of a class of drugs that prevent the action of *leukotrienes by blocking their receptors on cell membranes, such as those in the airways. These drugs are used in the management of asthma for their effects in relaxing the smooth muscle of the airways and in reducing inflammation in the bronchial linings. Examples are montelukast and zafirlukast; side-effects may include headache and abdominal pain or gastrointestinal upsets.... leukotriene receptor antagonist

see anti-oestrogen.... oestrogen-receptor antagonist