A long-acting, non-sedative antihistaminic used in the treatment of seasonal allergic rhinitis, asthma, allergic conjunctivitis, and chronic idiopathic urticaria. The drug is well tolerated and has no anticholinergic side effects. .

Hismanal - Pharmacology:

Hismanal 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. Hismanal may also act on H3-receptors, producing adverse effects.

Hismanal for patients

Patients taking Hismanal should receive the following information and instructions. Antihistamines are prescribed to reduce allergic symptoms. Patients taking Hismanal should be advised: 1) to adhere to the recommended dose, and 2) that the use of excessive doses may lead to serious cardiovascular events. DO NOT EXCEED THE RECOMMENDED DOSE. Some patients appear to increase the dose of Hismanal in an attempt to accelerate the onset of action. PATIENTS SHOULD BE ADVISED NOT TO DO THIS, and not to use Hismanal as a p r n product for immediate relief of symptoms. Patients should be questioned about use of another prescription or over-the-counter medication, and should be cautioned regarding the potential for life- threatening arrhythmias with concurrent use of ketoconazole, itraconazole, or erythromycin. Patients should be questioned about pregnancy or lactation before starting Hismanal therapy, since the drug should be used in pregnancy or lactation only if the potential benefit justifies the potential risk to fetus or baby. In addition, patients should be instructed to take Hismanal on an empty stomach e.g., at least 2 hours after a meal. No additional food should be taken for at least 1 hour after dosing. Patients should also be instructed to store this medication in a tightly closed container in a cool, dry place, away from heat or direct sunlight, and away from children.

Hismanal Interactions

Ketoconazole/Itraconazole, Macrolides, Including Erythromycin

Hismanal Contraindications

Concomitant administration of Hismanal with erythromycin is contraindicated because erythromycin is known to impair the cytochrome P450 enzyme system which also influences astemizole metabolism. There have been two reports to date of syncope with Torsades De Pointes, requiring hospitalization, in patients taking combinations of astemizole 10 mg daily with erythromycin. In each case the QT intervals were prolonged beyond 650 milliseconds the time of the event; One patient also received ketoconazole and the other patient also had hypokalemia.

Concomitant administration of astemizole with ketoconazole tablets is contraindicated because available human pharmacokinetic data indicate that oral ketoconazole significantly inhibits the metabolism of astemizole, resulting in elevated plasma levels of astemizole and desmethylastemizole. Data suggest that cardiovascular events are associated with elevation of astemizole and/or astemizole metabolite levels resulting in electrocardiographic QT prolongation.

Concomitant administration with itraconazole is also contraindicated based on the chemical resemblance of itraconazole and ketoconazole. In vitro data suggest that itraconazole has a less pronounced effect on the biotransformation system responsible for the metabolism of astemizole compared to ketoconazole.

Hismanal is contraindicated in patients with known hypersensitivity to astemizole or any of the inactive ingredients.

Generic name, Overdose, Half Life Hismanal, Food Interactions, Chemical, etc..

Hismanal see also

Brand Names containing Astemizole

Chemical structure:
N N F N O N H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H C28H31FN4O 2D chemical structure C28H31FN4O SVG | 2D structure chemical names, chemical properties, classification C28H31FN4O