Not to be used in emergency allergy situations. Patients w/ known cardiac risk eg, those w/ prolonged QT interval, hypokalaemia. Concomitant treatment w/ compd increasing QT interval or inhibiting CYP3A4 enzyme eg, azole antifungals (eg, ketoconazole & itraconazole) & macrolide antibiotics (eg, erythromycin). Concomitant use w/ rifampicin. Not to be used by patients w/ hereditary galactose intolerance, Lapp lactase deficiency or poor absorption of glucose or galactose. May affect ability to drive or use machinery in sensitive individuals. Severe hepatic impairment. Avoid use during pregnancy & lactation. Childn <12 yr.