Pandya, K.J., Raubertas, R.F., Flynn, P.J., Hynes, H.E., Rosenbluth, R.J., Kirshner, J.J., … Morrow, G.R. (2000). Oral clonidine in postmenopausal patients with breast cancer experiencing tamoxifen-induced hot flashes: A University of Rochester Cancer Center community clinical oncology program study. Annals of Internal Medicine, 132, 788–793.

The study evaluated oral clonidine in postmenopausal patients with breast cancer experiencing tamoxifen-induced hot flashes.

Participants received oral clonidine hydrochloride 0.1 mg daily or placebo at bedtime for eight weeks.

The study enrolled 198 postmenopausal women (mean age 71 years) with breast cancer taking tamoxifen and stratified by time since menopause (less than three years, more than three years), duration of tamoxifen use (less than one year; longer than one year), and baseline frequency of hot flashes (less than 10 per day, more than 10 per/day). One hundred forty-nine (149) completed the study. Of the participants, 99 received clonidine and 99 received the placebo.

• Inclusion criteria:
  • Postmenopausal women who had been receiving adjuvant tamoxifen therapy for breast cancer for at least one month and reported at least one hot flash per day
  • Normal hepatic and renal function
• Exclusion criteria:
  • Premenopausal women 
  • Women receiving concurrent chemotherapy or endocrine therapy for breast cancer, hypertension therapy or concurrent treatment with monoamine oxidase inhibitors; L-dopa, piribedil, tricyclic antidepressants, or sedatives
  • Coronary insufficiency, recent history of myocardial infarction (within three months), symptomatic cardiac disease, peripheral or cerebrovascular disease, syncope, or symptomatic hypotension
  • Allergy or adverse reaction to clonidine

A community oncology clinic conducted the study.

The study was a randomized, double blind, placebo-controlled trial.

Measures included:

• Daily hot flash diary for one week at baseline, during the weeks 4 and 8 during treatment, and four weeks after the end of treatment
• Symptom checklist

One hundred forty-nine (149) of 198 completed 12 weeks of follow-up (73 in clonidine group and 76 in placebo group.) Oral clonidine was shown to be effective. The mean decrease in hot flash frequency was greater in the clonidine group after week 4 (37% to 20%) and week 8 (38% to 24%). The clonidine group had more difficulty with sleep (41%–21%). A significant difference was seen in the mean change in QOL scale (p = 0.02) at 8 weeks.

Limitations included:

• Evaluation for eight weeks
• No evaluation of long-term effectiveness