[CNS activity of antihistaminics]

All the antihistamines tested, except astemizole, alter the S-W cycle in dogs. The changes are consistent with the well-known, sedative side-effects observed with most agents from this class. Astemizole, however, produced no EEG changes even at 50 times the effective antihistamine dose. This finding supports the clinical observation that the drug does not cause drowsiness or sedation.