INFORMATION FOR HEALTH PROFESSIONALS
Home | Consumers | Health Professionals | Regulatory | Other | Hot Topics | Search
Home | Consumers | Health Professionals | Regulatory | Other | Hot Topics | Search
The sponsor (pharmaceutical company) of this product has
advised Medsafe that this product has either been discontinued or is no longer
marketed in New Zealand.
Therefore this Data Sheet may not be up to date.
Medsafe has elected to leave it on this web site because supplies of this
product may still be available, and health professionals should continue to
have access to this product information in the interim.
You may be able to find a more current Data Sheet containing the same medicine
by returning to the main Data Sheet page and searching by ingredient name.
ZADINE azatadine maleate 1 mg Tablet
White, round tablet scored on one side, marked with company logo on the other side
Azatadine is a potent long-acting H1-receptor antagonist possessing anti-serotonergic, anticholinergic and antianaphylactic activity.
The antihistaminic action of azatadine appears to be twofold:
Inhibition of the action of histamine either exogenously administered or discharged from the cell.
Inhibition of histamine release from cells during anaphylaxis.
In an in vivo comparative study with chlorpheniramine, promethazine, diphenhydramine, cyproheptadine, phenindamine, chlorpyrilene, tripelennamine and chlorcyclizine, azatadine was found to be 7.4 times more potent than cyproheptadine and 12 to 304 times more potent than the other antihistamines, in preventing histamine lethality in guinea pigs. In the prevention of histamine lethality in mice it was 4 times more potent than cyproheptadine. Azatadine was 70 times more potent than cyproheptadine and 25 to 1700 times more potent than the other antihistamines in delaying the onset of histamine-induced dyspnoea in guinea pigs.
The anticholinergic activity of azatadine was greater than 13 times that of cyproheptadine and the other antihistamines studied in vivo.
Azatadine was approximately one-seventh as potent as cyproheptadine, and more than 10 times more potent than the other antihistamines in delaying the onset of serotonin-induced dyspnoea in guinea pigs.
Azatadine maleate (1.5 mg/kg) completely blocked histamine-induced weal formation in rats.
In vitro, azatadine has been shown to inhibit antigen-induced histamine release and in vivo has been shown to substantially decrease both the symptomatology and release of mediators following nasal allergen challenge of allergic individuals.
Pharmacokinetic studies in normal volunteers dosed orally with radiolabelled azatadine maleate show that the drug is readily absorbed (greater than 90%) with peak plasma levels at 3-4 hours after dosing. Clinical data have shown that the onset of relief of symptoms generally occurs 2 to 3 hours after dosing.
Approximately 57% of the drug is excreted in the urine within 5 days after administration of a single dose, and no evidence of drug accumulation was seen after daily dosing for 30 days. The elimination half-life of azatadine maleate, based on plasma radioactivity, was approximately 9 hours. Approximately 20% of the drug is excreted unchanged and extensive conjugation of the drug and its metabolites occurs.
Azatadine maleate is minimally bound to plasma protein.
Symptomatic relief of allergic respiratory conditions (e.g., acute and chronic allergic rhinitis, hay fever), allergic dermatological conditions (e.g., acute and chronic urticaria, allergic eczema, contact dermatitis, insect bites). As an adjunct to therapy of angioneurotic oedema, drug and serum reactions.
Symptomatic relief of vasomotor rhinitis.
Adults: In most conditions, 1 tablet every twelve hours (morning and evening) is recommended in the majority of patients. In refractory or more severe cases, 2 tablets twice daily may be used.
Children: ½ to 1 tablet every twelve hours.
ZADINE is contraindicated in patients who are hypersensitive to azatadine maleate or other antihistamines of similar chemical structure.
Antihistamines in general are contraindicated in patients receiving monoamine oxidase inhibitor therapy.
Antihistamines should be used with caution in patients with narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction and urinary bladder obstruction due to symptomatic prostatic hypertrophy and narrowing of the bladder neck.
Antihistamines have additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquillisers, etc.).
Patients should be warned about engaging in activities requiring mental alertness, such as driving a car or operating machinery, certain appliances, etc. until their response to this medication has been determined.
Some clinical studies suggest that drowsiness, loss of concentration, and impaired psychomotor performance are unlikely to occur with ZADINE at the recommended doses of 1 to 2 mg twice daily.
Antihistamines are more likely to cause dizziness, sedation, and hypotension in patients over 60 years of age. ZADINE has atropine-like action and therefore should be used with caution in patients with increased intraocular pressure, hyperthyroidism, cardiovascular disease or hypertension.
Safety in pregnancy has not been established. Therefore ZADINE is not recommended for use in pregnant women. Teratologic studies in rodents showed no significant adverse effects on conception, development of the embryo, sex ratio, course of pregnancy, or parturition.
As ZADINE is contraindicated in newborn and premature infants, it is not recommended for nursing mothers unless the expected benefits outweigh the potential risk.
Antihistamines should be discontinued about four days prior to skin testing procedures since these drugs may prevent or diminish otherwise positive reactions to dermal reactivity indicators.
The physician should be alerted to the possibility of the following adverse effects associated with antihistamines in general:
General: Urticaria, drug rash, anaphylactic shock, photosensitivity, excessive perspiration, chills, dryness of mouth, nose and throat.
Cardiovascular: Hypotension, headache, palpitations, tachycardia, extrasystoles.
Hematological: Haemolytic anaemia, thrombocytopenia, agranulocytosis, hypoplastic anaemia, pancytopenia.
Nervous: Sedation, sleepiness, dizziness, vertigo, tinnitus, acute labyrinthitis, disturbed co-ordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paraesthesia, blurred vision, diplopia, hysteria, neuritis, convulsions, nightmares, hallucinations, mood changes.
Gastrointestinal: Epigastric distress, anorexia, nausea, vomiting, diarrhoea, constipation.
Genito-urinary: Urinary frequency, difficult urination, urinary retention, early menses.
Respiratory: Thickening of bronchial secretions, tightness of chest and wheezing, nasal stuffiness.
Monoamine oxidase inhibitors prolong and intensify the effects of antihistamines; severe hypotension may occur. Concomitant use with alcohol, tricyclic antidepressants, barbiturates or other central nervous system depressants may potentiate any sedative effects of antihistamines. The action of oral anticoagulants may be inhibited by antihistamines.
In the event of overdosage, emergency treatment should be started immediately.
Antihistamine overdosage effects may vary from central nervous system depression (sedation, apnoea, diminished mental alertness, cardiovascular collapse) to stimulation (insomnia, hallucinations, tremors or convulsions) to death. Other signs and symptoms may be dizziness, tinnitus, ataxia, blurred vision and hypotension. Stimulation is particularly likely in children, as are atropine-like signs and symptoms (dry mouth; fixed, dilated pupils; flushing, hyperthermia; gastrointestinal symptoms).
There is no specific therapy for poisoning with H1-antagonists. Treatment is generally symptomatic and supportive.
Nil
Restricted Medicine
Pack 50 tablets
Nil
Schering-Plough Pty Limited
33 Whakatiki Street
Upper Hutt
Wellington
NEW ZEALAND
14 December 2005