Of sedating antihistamines Veronica juggs webcam
There are two different types of antihistamine – the older group, sedating antihistamines, can enter the brain and cause drowsiness, while the newer non-sedating antihistamines do not.
Itching can occur during the day but is usually worse in early evening and at night, so sedating antihistamines are used because they help make you sleepy, as well as reducing the itch.
However, if itching is still a problem your doctor may prescribe you an antihistamine.
Antihistamines are most commonly used to control the symptoms of allergies such as hay fever.
Where possible we studied the immediate effect and the effect after six to 10 days.
Most studies were of good quality although in some studies information to allow us to assess quality was lacking.
It is caused by viruses and usually resolves by itself within one to two weeks.
However, the common cold has a large impact on time off work or school.
Study characteristics The evidence is current to August 2015.In these conditions they work by preventing the actions of histamine, which is a substance produced by the body as part of its natural defences.It's stored in cells called mast cells, in almost all tissues of the body, and is released when the body reacts to a foreign substance (known as an allergen).The released histamine binds to its receptors (H-1 receptors) causing a chain reaction that includes an increase in blood flow to the area, and the release of other chemicals that add to the allergic response. Antihistamines work by blocking histamine receptors, therefore reducing the reactions that cause itching.However, histamine is only one of many substances in the body that cause itching, and these medicines are mainly of value in eczema because they cause sedation.