Patients w/ severe liver impairment; not for patients w/ rare hereditary problems of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption. Discontinue at least 48 hr before skin tests as antihistamines may prevent or reduce otherwise positive reactions to dermal reactivity index. Very rarely, some patients may experience drowsiness; may affect their ability to drive or use machines. Pregnancy & lactation. Childn <2 yr. Not for childn w/ body wt <30 kg.