Antihistamines sedating effect
The participants were adults or children with a common cold.
We excluded studies with participants suffering from hay fever, asthma or eczema.
It is caused by viruses and usually resolves by itself within one to two weeks.
For example, when you're fighting a cold (the rhinovirus), histamines widen the blood vessels in your nasal cavity, causing nasal congestion.
Side Effects- Some can cause drowsiness, but non-sedating types are available.
Drowsiness is one of the major side effects of some antihistamines, such as diphenhydramine (Benadryl) and doxylamine succinate (the antihistamine found in Nyquil).
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.