Figure legends
FIGURE 1. Gene polymorphism affects the efficacy and adverse reactions of antihistamines. As a reverse agonist, antihistamine acts on the histamine receptor to antagonize the histamine effect, exerting the antihistamine and anti-allergic effect. Antihistamines complete the process of absorption, distribution, metabolism and excretion under the action of drug transporter and the cytochromes P450(CYPs). Mast cells, one of the main histamine-releasing cells, express multiple receptors on the surface. Polymorphisms of these receptor-related genes, histamine receptor, transporter and metabolic enzyme related genes may affect drug efficacy and adverse reactions.
Table 1. Effects of metabolic enzymes, drug transporters, and drug target receptor gene polymorphisms on antihistamine drug therapy and adverse reactions.