Mechanism of action of sedating antihistamines
In addition, each compound can have or not have parallel properties, antimuscarinic effects for example.
This distinction between generations must be taken with caution because a product considered as non sedative or not antimuscarinic can, in certain circumstances, large doses or particular susceptibility of the patient ,have these effects.
For example, when you're fighting a cold (the rhinovirus), histamines widen the blood vessels in your nasal cavity, causing nasal congestion.
Additionally, the increased fluid leakage from your blood vessels, combined with an increased mucous production — also caused by histamines — can result in a runny nose.
Allergies occur when your immune system erroneously thinks an innocuous foreign substance, such as pollen or pet dander, is actually dangerous.