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The impact of the Women’s Health Initiative study on incident clonidine use in Ontario, Canada


Background — Following publication of the Women's Health Initiative (WHI) study, many women discontinued use of estrogen replacement therapy. There is some evidence that the antihypertensive agent clonidine can reduce the frequency of hot flashes associated with menopause.

Objectives — To determine the impact of the WHI study on incident use of clonidine in elderly women in Ontario, Canada.

Methods — Retrospective, population-based administrative database design. Data on all residents of Ontario over the age of 65 years were included. Time series methods were used to analyze change in incident clonidine use following publication of the WHI study.

Results — Following publication of the WHI study, incident use of clonidine increased substantially among elderly women in Ontario, Canada. Similar trends were not observed for incident use of other antihypertensive medications.

Conclusion — During a period of time in which a large proportion of women discontinued estrogen replacement therapy, incident use of clonidine increased. There is some evidence that a small number of women may have sought alternative relief from menopausal symptoms using other pharmacological therapies.



Austin PC, Mamdani MM, Tu K. Can J Clin Pharmacol. 2004; 11(2):e191-4. Epub 2004 Sep 3.

Contributing ICES Scientists