Drug Safety

, Volume 10, Issue 5, pp 350–380

H1-Receptor Antagonists

Comparative Tolerability and Safety
  • F. Estelle R. Simons
Review Article Drug Experience

DOI: 10.2165/00002018-199410050-00002

Cite this article as:
Simons, F.E.R. Drug-Safety (1994) 10: 350. doi:10.2165/00002018-199410050-00002


First-generation histamine H1-receptor antagonists, such as diphenhydramine, triprolidine, hydroxyzine or chlorpheniramine (chlorphenamine), frequently cause somnolence or other CNS adverse effects. Second-generation H1-antagonists, such as terfenadine, astemizole, loratadine and cetirizine, represent a true advance in therapeutics. In manufacturers’ recommended doses, they have a more favourable benefit/risk ratio than their predecessors with regard to lack of CNS effects, and do not exacerbate the adverse CNS effects of alcohol or other CNS-active chemicals. Rarely, some of the newer H1-antagonists may cause cardiac dysrhythmias after overdose or under other specific conditions. The concept of a risk-free H1-antagonist is proving to be an oversimplification. An H1-antagonist absolutely free from adverse effects under all circumstances is not yet available for use. The magnitude of the beneficial effects of each H1-antagonist should be related to the magnitude of the unwanted effects, especially in the CNS and cardiovascular system, and a benefit-risk ratio or therapeutic index should be developed for each medication in this class.

Copyright information

© Adis International Limited 1994

Authors and Affiliations

  • F. Estelle R. Simons
    • 1
  1. 1.Department of Pediatrics and Child Health, Section of Allergy and Clinical Immunology, Faculty of MedicineUniversity of ManitobaWinnipegCanada
  2. 2.Room AE101, Children’s Hospital of WinnipegWinnipegCanada

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