Main unwanted side effect of sedating antihistamines
Anxiety and agitation with diffuse, deep, odd body sensations:"..bones are on fire", "I feel weird all over", "...a deep pricking, crawling sensation...".
Histamine carries its message to a large number of cells by attaching to a special receptor on the cells' surfaces.
To get a good idea of what histamine can do, let us imagine the effects of an injection of a small amount of histamine: Headache is felt as a pulsating, whole-head pain, often with a sense of pressure.
Once released, the histamine can react with local or widespread tissues through histamine receptors.Sedation and cognitive changes occur with initiation of therapy or dose escalation.Underlying disease states or other centrally acting medications often will compound the opioid’s adverse effects.After oral administration, ketotifen is completely absorbed, with peak concentrations occurring at about 3 hours. The absorbed drug is distributed extensively to circulating cells and 16–18% is bound to plasma proteins.Some 69–70% of the dose is excreted as metabolites.