Brands, Medical Use, Clinical Data
Brands / Synonyms
Azatadina [INN-Spanish]; Azatadine Maleate; Azatadinum [INN-Latin]; Azatidine; Optimine
For the relief of the symptoms of upper respiratory mucosal congestion in perennial and allergic rhinitis, and for the relief of nasal congestion and eustachian t.b. congestion.
Azatadine is an antihistamine, related to cyproheptadine, with anti-serotonin, anticholinergic (drying), and sedative effects. Azatadine is in the same class of drugs as chlorpromazine (Thorazine) and trifluoperazine (Stelazine); however, unlike the other drugs in this class, azatadine is not used clinically as an anti-psychotic. Antihistamines antagonize the vasodilator effect of endogenously released histamine, especially in small vessels, and mitigate the effect of histamine which results in increased capillary permeability and edema formation. As consequences of these actions, antihistamines antagonize the physiological manifestations of histamine release in the nose following antigen-antibody interaction, such as congestion related to vascular engorgement, mucosal edema, and profuse, watery secretion, and irritation and sneezing resulting from histamine action on afferent nerve terminals.
Mechanism of Action
Antihistamines such as azatadine appear to compete with histamine for histamine H1- receptor sites on effector cells. The antihistamines antagonize those pharmacological effects of histamine which are mediated through activation of H1- receptor sites and thereby reduce the intensity of allergic reactions and tissue injury response involving histamine release.
Well absorbed after oral administration.
The oral LD50 in mature rats and mice was greater than 1700 mg/kg and 600 mg/kg, respectively. Symptoms of overdose include clumsiness or unsteadiness, seizures, severe drowsiness, flushing or redness of face, hallucinations, muscle spasms (especially of neck and back), restlessness, shortness of breath, shuffling walk, tic-like (jerky) movements of head and face, trembling and shaking of hands, and insomnia.
Biotrnasformation / Drug Metabolism
Antihistamines should not be used to treat lower respiratory tract symptoms, including asthma. This product is
contraindicated in patients with narrow-angle glaucoma or urinary retention, and in patients receiving monoamine
oxidase (MAO) inhibitor therapy or within 2 weeks of stopping such treatment. It is also contraindicated in patients
with severe hypertension, severe coronary artery disease, hyperthyroidism, and in those who have shown
hypersensitivity or idiosyncrasy to its components, to adrenergic agents, or to other drugs of similar chemical
structures. Manifestations of patient idiosyncrasy to adrenergic agents include: insomnia, dizziness, weakness,
tremor, or arrhythmias.
MAO inhibitors prolong and intensify the effects of antihistamines. Concomitant use of antihistamines with
alcohol, tricyclic antidepressants, barbiturates, or other central nervous system depressants may have an additive
When sympathomimetic drugs are given to patients receiving monoamine oxidase inhibitors, hypertensive reactions,
including hypertensive crises, may occur. The antihypertensive effects of methyldopa, mecamylamine, reserpine, and
veratrum alkaloids may be reduced by sympathomimetics. Beta-adrenergic blocking agents may also interact with
sympathomimetics. Increased ectopic pacemaker activity can occur when pseudoephedrine is used concomitantly with
digitalis. Antacids increase the rate of absorption of pseudoephedrine, while kaolin decreases it.