Antihistamine drugs

A group of drugs that block the effects of histamine, a chemical released in allergic reactions (see allergy). Antihistamines are used to treat rashes such as urticaria and to relieve sneezing and a runny nose in allergic rhinitis. They are also sometimes included in cough remedies and cold remedies and are used as antiemetic drugs. Antihistamines are usually taken by mouth but may be given by injection for anaphylactic shock. Many antihistamines cause drowsiness, but newer drugs have little sedative effect. Other possible side effects include loss of appetite, nausea, dry mouth, blurred vision, and difficulty in passing urine.


Online Medical Dictionary: Your essential reference to over 5000 medical terms.