2886 Astemizole Astemizole is a long-acting, non-sedating second generation antihistamine used in the treatment of allergy symptoms. It was withdrawn from market by the manufacturer in 1999 due to the potential to cause arrhythmias at high doses, especially when when taken with CYP inhibitors or grapefruit juice. 68844-77-9 2247 C28H31FN4O 458.248190 White powder. 149.1°C 432 mg/L Oral. Rapidly absorbed from the gastrointestinal tract. Astemizole competes with histamine for binding at H₁-receptor sites in the GI tract, uterus, large blood vessels, and bronchial muscle. This reversible binding of astemizole to H₁-receptors suppresses the formation of edema, flare, and pruritus resulting from histaminic activity. As the drug does not readily cross the blood-brain barrier and preferentially binds at H1 receptors in the peripehery rather than within the brain, CNS depression is minimal. Astemizole may also act on H₃-receptors, producing adverse effects. It is metabolized by CYP3A4. [Wikidpedia]. Almost completely metabolized in the liver and primarily excreted in the feces. Half Life: 1 day LD50: 2052mg/kg (Mouse) (A308) No indication of carcinogenicity to humans (not listed by IARC). Astemizole tablets are indicated for the relief of symptoms associated with seasonal allergic rhinitis and chronic idiopathic urticaria. (L1864). Astemizole was indicated for use in the relieving allergy symptoms, particularly rhinitis and conjunctivitis. It has been withdrawn from the market however due to concerns of arrhythmias. Cardiovascular adverse events. In some cases, recognition of severe arrhythmias has been preceded by episodes of syncope. Similarly, rare cases of hypotension, palpitations, and dizziness have also been reported with Astemizole use, which may reflect undetected ventricular arrhythmia. (L1864) In the event of overdosage, supportive measures including gastric lavage and emesis should be employed. (L1712) 2009-07-21T20:27:18Z 2014-12-24T20:25:52Z Astemizole C06832 2896 Astemizole DB00637 true COC1=CC=C(CCN2CCC(CC2)N=C2NC3=CC=CC=C3N2CC2=CC=C(F)C=C2)C=C1 C28H31FN4O InChI=1S/C28H31FN4O/c1-34-25-12-8-21(9-13-25)14-17-32-18-15-24(16-19-32)30-28-31-26-4-2-3-5-27(26)33(28)20-22-6-10-23(29)11-7-22/h2-13,24H,14-20H2,1H3,(H,30,31) InChIKey=GXDALQBWZGODGZ-UHFFFAOYSA-N 458.5703 458.248189839 Exogenous Solid 5.8 HMDB14775 CHEMBL296419 2160 <p>Godelieve Irma Christine Maria Heylen, Cornelus Gerardus Maria Janssen, Jurzak Mirek, Henricus Petrus Martinus Maria Van Assouw, &#8220;Radiolabeled astemizole and method of making.&#8221; U.S. Patent US07541476, issued June 02, 2009.</p>