Cetirizine dihydrochloride.
Pharmacodynamics: Cetirizine is a potent antihistamine with a low potential for drowsiness at normal therapeutic doses which has additional antiallergic properties. It is a selective H1-antagonist with negligible effects on other receptors and so, is virtually free from anticholinergic and anti-serotonin effects. Cetirizine inhibits the histamine-mediated early phase of the allergic reaction and also reduces the migration of certain inflammatory cells abd the release of certain mediators associated with the late allergic response.
Pharmacokinetics: Peak blood levels of the order of 0.3 mcg/mL are reached between 30 and 60 min after the oral administration of a 10-mg dose of cetirizine. The terminal half-life is approximately 10 hrs in adult and 6 hrs in children 6-12 yrs. This is consistent with the urinary excretion half-life of the drug. The cumulative urinary excretion represents about two-thirds of the administered dose for both adults and children. The apparent plasma clearance in children is higher than that measured in adults. A high proportion of cetirizine is bound to human plasma proteins.
Symptomatic treatment of perennial rhinitis, seasonal allergic rhinitis and chronic idiopathic urtcaria in adults and children aged ≥6 years.
Adults and children ≥6 years: 1 tab/day.
Moderate to Severe Renal Impairment: Reduce to half the recommended dose.
Drowsinesss can be a symptom of overdosage. In children, agitation can occur. In the case of massive overdosage, alvage should be performed together with the usual supportive measures. To date, there is no specific antidote.
Patients with a history of hypersenstivity to any of the constituents of Histacet.
Use in lactation: Histacet is contraindicated during lactation.
In patients with moderate to severe renal impairment, the dosage should be reduced to half the usual recommended daily dose.
Effects on the Ability to Drive or Operate Machinery: Studies in healthy volunteers at 20 and 25 mg/day have not revealed adverse effects on alertness or reaction time. However, patients are advised not to exceed the recommended dose if driving or operating machinery.
Use in pregnancy: No adverse effects have been reported from animal studies. There has been little or no clinical experience of Histacet during pregnancy. As with other drugs, the use of cetirizine in pregancy should be avoided.
Use in children: At present, there are insufficient clinical data to recommend the use of cetirizine in children <2 years. For the time being, there is no data to suggest that the dose needs to be reduced in elderly patients.
Use in pregnancy: No adverse effects have been reported from animal studies. There has been little or no clinical experience of Histacet during pregnancy. As with other drugs, the use of cetirizine in pregancy should be avoided.
Use in lactation: Histacet is contraindicated during lactation.
In objective tests of psychomotor function, the incidence of sedation with cetirizine was similar to that of placebo. There have been occasional reports of mild and transient side effects eg, headache, dizziness, drowsiness, agitation, dry mouth and gastrointestinal discomfort. If affected, the dose may be taken as 5 mg on the morning, and 5 mg in the evening.
To date, there are no known interactions with other drugs. Studies with diazepam and cimetidine have revealed no evidence of interactions. As with other antihistamines, it is advisable to avoid excessive alcohol consumption.
Incompatibilities: None.
Store below 25°C.
Shelf-life: 3 years.
R06AE07 - cetirizine ; Belongs to the class of piperazine derivatives used as systemic antihistamines.
Histacet film-coated tab 10 mg
2 × 10's
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