Astemizole

About: Astemizole is a research topic. Over the lifetime, 541 publications have been published within this topic receiving 15233 citations. The topic is also known as: 1-(p-fluorobenzyl)-2-{[1-(p-methoxyphenethyl)-4-piperidyl]amino}benzimidazole & 1-(p-fluorobenzyl)-2-({1-[2-(p-methoxyphenyl)ethyl]piperid-4-yl}amino)benzimidazole.

H1-receptor antagonists. Comparative tolerability and safety.

Abstract: First-generation histamine H1-receptor antagonists, such as diphenhydramine, triprolidine, hydroxyzine or chlorpheniramine (chlorphenamine), frequently cause somnolence or other CNS adverse effects. Second-generation H1-antagonists, such as terfenadine, astemizole, loratadine and cetirizine, represent a true advance in therapeutics. In manufacturers' recommended doses, they have a more favourable benefit/risk ratio than their predecessors with regard to lack of CNS effects, and do not exacerbate the adverse CNS effects of alcohol or other CNS-active chemicals. Rarely, some of the newer H1-antagonists may cause cardiac dysrhythmias after overdose or under other specific conditions. The concept of a risk-free H1-antagonist is proving to be an oversimplification. An H1-antagonist absolutely free from adverse effects under all circumstances is not yet available for use. The magnitude of the beneficial effects of each H1-antagonist should be related to the magnitude of the unwanted effects, especially in the CNS and cardiovascular system, and a benefit-risk ratio or therapeutic index should be developed for each medication in this class.

Antiallergic drugs and the immune response. Interactions and possible clinical relevance.

Abstract: Since the pharmacological treatment of allergic diseases is used in patients with alteration of the immune response due to atopy and possible concomitant infections, we have investigated the possible effects of such drugs as cromolyn, theophylline, ketotifen, oxatomide, astemizole, fenoterol, pirenzepine, and rosaprostol on the in vitro immune response, in order to obtain experimental data and, as a consequence, clinical conclusions. In a series of investigations by our group and other authors the following immunological parameters have been considered: T cell activation induced by different pathways (i.e. autologous stimulation, PHA, anti-CD3, -CD2 and -CD28 monoclonal antibodies), and lymphokine production (i.e. IL-1, IL-2 and gamma-IFN). For a more detailed experimental model the experiments have been performed both in bulk culture and by using T cell clones derived from the peripheral blood. The results show cromolyn to have an enhancing effect, theophylline and ketotifen a suppressing effect, whereas the remainder show no effect on the immune response. These data are considered and discussed from the aspect of their possible clinical relevance and also in light of the in vivo data previously reported.

A clinical drug library screen identifies astemizole as an antimalarial agent

Abstract: The high cost and protracted time line of new drug discovery are major roadblocks to creating therapies for neglected diseases. To accelerate drug discovery we created a library of 2,687 existing drugs and screened for inhibitors of the human malaria parasite Plasmodium falciparum. The antihistamine astemizole and its principal human metabolite are promising new inhibitors of chloroquine-sensitive and multidrug-resistant parasites, and they show efficacy in two mouse models of malaria.

Astemizole. A review of its pharmacodynamic properties and therapeutic efficacy.

Abstract: Astemizole is an H1-histamine receptor antagonist with a long duration of action permitting once daily administration. Its efficacy in seasonal and perennial allergic rhinitis has been convincingly demonstrated, and several comparative studies suggest that astemizole is at least as effective as some other H1-histamine receptor antagonists. A few smaller studies have shown beneficial effects on the symptoms of allergic conjunctivitis and chronic urticaria (but not atopic dermatitis). While astemizole appears to share with other H1-histamine receptor antagonists a tendency to increase appetite and cause weight gain after prolonged use, it offers the important advantage of an absence of significant central nervous system depression or anticholinergic effects with usual doses. Thus, astemizole offers a worthwhile improvement in side effect profile over 'traditional' H1-histamine receptor antagonists, especially in patients bothered by the sedative effects of these drugs.

Cardiac Actions of Antihistamines

Abstract: Two of the nonsedating antihistaminic drugs, terfenadine and astemizole, have recently been recognized in rare cases to induce the syndrome of torsades de pointes, i.e. QT interval prolongation and life-threatening ventricular tachycardia. Each was found to prolong cardiac repolarization when its metabolic elimination was impaired, such as by liver disease or drugs that inhibit the 3A family of cytochrome P450. In vitro studies indicate that this action is due to blockade of one or more of the cardiac potassium channels that determine the duration of the action potential. Prescription guidelines are now available to reduce the risk of developing arrhythmias with these two drugs. Two agents recently marketed in the United States, Ioratidine and cetirizine, appear to lack the ability to prolong repolarization and induce torsades de pointes. Evaluation of the potential cardiac actions of investigational antihistamines is essential and may be of value for some of the older conventional agents.