A comprehensive review with 185 references for the analysis of commonly prescribed members of an important class of drugs, non-sedating antihistamines (NSAs), is presented.The review covers most of the methods described for the analysis of cetirizine (CTZ), ebastine (EBS), fexofenadine (FXD), ketotifen (KET) and loratadine (LOR) in pure forms, in different pharmaceutical dosage forms and in biological fluids. H1-receptor antagonists (H1-antihistamines) that competitively block histamine at H1-receptors have been used in the treatment of allergic conditions for many years.Clinically useful H1-antihistamines such as phenbenzamine, pyrilamine, and diphenhydramine were introduced in the 1940s.

meaning of non sedating-77

Brompheniramine and chlorpheniramine are typical alkylamine antihistamines. They cause moderate sedation (despite having weak CNS effects), gastric disturbances, and skin sensitization.

Antazoline, mepyramine and tripelennamine are examples. this group of antihistamines possesses moderate sedative and significant antiemetic actions.

Piperazine derivatives include cetirizine, cyclizine, and hydroxyzine.

Cetirizine causes less sedation than other members of this group.

they cause moderate or low sedation and are highly selective for H1 receptors.

Examples include azatadine, cyproheptadine, and non-sedating antihistamines (astimazole, desloratadine, ebastine, fexofenadine, loratadine, and terfenadine).; also known as ‘sedating antihistamines’, First-generation H1 antihistamines such as alimemazine, chlorphenamine, clemastine, cyproheptadine, hydroxyzine, and promethazine are non-selective in binding to the H1 receptor.Most of these drugs have weak antimuscarinic anticholinergic effects, some have alpha-adrenergic blocking effects (promethazine), and others can inhibit both histamine and 5-hydroxytryptamine activity (cyproheptadine).Owing to their lipophilicity, relatively low molecular weight, and lack of recognition by the P-glycoprotein efflux pump, first-generation H1 antihistamines readily penetrate the non-fenestrated capillaries of the central nervous system (blood brain barrier) and bind to central H1 receptors, interfering with the actions of histamine on these receptors. Second-generation H1-antihistamines such as cetirizine (CTZ), Ebastine (EBS), ketotifen (KET), loratadine (LOR) are newer drugs that are much more selective for peripheral H1 receptors as opposed to the central nervous system H1 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.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, that is why they produce very little or no sedation.