Names of non sedating antihistamines
The reason for their peripheral selectivity is that most of these compounds are zwitterionic at physiological p H (around p H 7.4).
As such, they are very polar, meaning that they do not cross the blood–brain barrier and act mainly outside the central nervous system.
The second-generation H receptors and cholinergic receptors.
This selectivity significantly reduces the occurrence of adverse drug reactions, such as sedation, while still providing effective relief of allergic conditions.
Significant anticholinergic adverse effects, as well as sedation, are observed in this group but the incidence of gastrointestinal adverse effects is relatively low.
They are effective in the relief of allergic symptoms, but are typically moderately to highly potent muscarinic acetylcholine receptor (anticholinergic) antagonists as well.
These agents also commonly have action at α-adrenergic receptors and/or 5-HT receptors.
In severe allergies, such as anaphylaxis or angioedema, these effects may be of life-threatening severity.
Additional administration of epinephrine, often in the form of an autoinjector (Epi-pen), is required by people with such hypersensitivities.-antihistamines can be administered topically (through the skin, nose, or eyes) or systemically, based on the nature of the allergic condition.