Hydroxyzine

Hydroxyzine is a histamine H₁ receptor antagonist (K_i = 1.9 nM).¹ It binds competitively with the H₁ receptor inverse agonist mepyramine (Item No. 20978) with an IC₅₀ value of 80 µM in polymorphonuclear leukocytes.² In vivo, it is metabolized to the H₁ receptor antagonist cetirizine (Item No. 19686).³ In situ, hydroxyzine (10 µM) prevents recruitment of rolling leukocytes induced by histamine in rat mesentery post-capillary venules.⁴ Hydroxyzine also decreases anxiety-like behavior in mice, increasing the time spent in the open arms of the elevated plus maze and in the light side of the light-dark exploration test.⁵ Formulations containing hydroxyzine have been used in the treatment of anxiety and as antihistamines in the treatment of allergic rhinitis.

WARNING This product is not for human or veterinary use.

1. Gillard, M., Van Der Perren, C., Moguilevsky, N., et al. Binding characteristics of cetirizine and levocetirizine to human H1 histamine receptors: Contribution of Lys191 and Thr¹⁹⁴. Mol. Pharmacol. 61(2), 391-399 (2002).

2. Wescott, S., and Kaliner, M. Histamine H₁ binding site on human polymorphonuclear leukocytes. Inflammation 7(3), 291-300 (1983).

3. Obach, R.S. Pharmacologically active drug metabolites: Impact on drug discovery and pharmacotherapy. Pharmacol. Rev. 65(2), 578-640 (2013).

4. Asako, H., Kurose, I., Wolf, R., et al. Role of H1 receptors and P-selectin in histamine-induced leukocyte rolling and adhesion in postcapillary venules. J. Clin. Invest. 93(4), 1508-1515 (1994).

5. Sawantdesai, N.S., Kale, P.P., and Savai, J. Evaluation of anxiolytic effects of aripiprazole and hydroxyzine as a combination in mice. J. Basic Clin. Pharm. 7(4), 97-104 (2016).