Non sedating antihistamine drugs rachele brook smith and kenny wormald dating
H1-antihistamines have been used for more than fifty years in treating various allergic manifestations. H1-antihistamines which penetrate into brain elicit, by inhibiting stimulant effect of histamine, drowsiness.
In addition to this antihistamine effect, they can have parallel pharmacological properties, for example antimuscarinic and adrenolytic effects which must be considered.
It is used in treatment of chronic urticaria, atopic dermatitis and dermographisms. Doxylamine is a sedating antihistamine also used as an hypnotic.
The two first H1-antihistamines without sedating effect to be marketed were terfenadine and astemizole.
The first-genaration antihistamines have alpha adrenolytic activity which can decrease the vasoconstrictive effect of adrenaline and noradrenaline and an antimuscarinic effect with the corresponding adverse effects.
Certain H1 antagonists, such as promethazine, have a local anesthetic effect.
Protocol-directed sedation versus non-protocol-directed sedation in mechanically ventilated intensive care adults and children.
Antihistamines are inhibitors of histamine receptors. H1-antihistamines, inhibit competitively H1 receptors and the corresponding effects i. They do not inhibit antigen/antibodies reactions, nor histamine release, they inhibit H1 effects.
H1-antihistamines are used for supportive care of allergic manifestations, cutaneous (urticaria) or mucous membranes (rhinitis, hayfever, conjunctivitis). Insufficient alone to treat anaphylactic shock or edema of the larynx, they could prevent them.
The drug to use in severe situations is adrenaline The early H1-antihistamines usually induce drowsiness and their prescription to patients with an activity requiring a normal vigilance, like control of a vehicle, is contra-indicated.
By their alpha-adrenolytic effect especially when they are given by parenteral route, they could reduce the vasoconstrictive effect of adrenaline, administered for example in case of anaphylactic shock.
New H1-antihistamines induce only exceptionally drowsiness. This possibility, even rare, must however be taken into account, particularly at time of a first prescription.