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.