Astemizole is a histamine H1-receptor antagonist. Astemizole competitively binds to histamine H1-receptor sites in the gastrointestinal tract, uterus, blood vessels, and bronchial muscle. This suppresses the formation of edema and pruritus caused by histamine. Astemizole is structurally similar to terfenadine and haloperidol; it has anticholinergic and antipruritic effects.

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 24 months.
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.

[1]. Laduron PM, et al. In vitro and in vivo binding characteristics of a new long-acting histamine H1 antagonist, astemizole. Mol Pharmacol. 1982 Mar;21(2):294-300. [2]. Richards DM, et al. Astemizole. A review of its pharmacodynamic properties and therapeutic efficacy. Drugs. 1984 Jul;28(1):38-61.