Of sedating antihistamines
This is what gives them a potential for abuse and addiction.
The few cases of antihistamine addiction reported in the medical literature are mainly on diphenhydramine (DPH).
Allergic symptoms occur when your body wrongly recognises a food or something (such as pollen spores) in your environment as a threat, and sends repair chemicals to deal to these perceived intruders.
One of these repair chemicals, histamine, is released from repair cells called mast cells, which are scattered throughout the body.
Antihistamines, in general, have a low potential for addiction if you take them in the recommended doses for a short time.
However, if you take the older (first generation), sedating antihistamines in higher doses for a prolonged time, you run the risk of physical dependence and addiction, as well as more severe adverse side effects.
The non-sedating antihistamines include cetirizine, desloratadine, fexofenadine, levocetirizine and loratadine.