Oral clonidine in postmenopausal patients with breast cancer experiencing tamoxifen-induced hot flashes: A University of Rochester cancer center community clinical oncology program study

Background: Hot flashes are the most frequently reported side effect of tamoxifen treatment. Although hormones are an effective treatment, their safety is questionable in women with breast cancer. It is therefore important to evaluate nonhormonal treatments for hot flashes. Objective: To evaluate the effectiveness of oral clonidine for control of hot flashes associated with tamoxifen therapy in postmenopausal women with breast cancer. Design: Randomized, double-blind, placebo-controlled clinical trial. Setting: University of Rochester Cancer Center Community Clinical Oncology Program. Patients: 194 postmenopausal women with breast cancer who were receiving adjuvant tamoxifen therapy. Intervention: Oral clonidine hydrochloride, 0.1 mg/d, or placebo for 8 weeks. Measurements: In a daily diary, patients recorded number, duration, and severity of hot flashes and overall quality-of-life score (on a 10-point scale) during a 1-week baseline period and during the 4th, 8th, and 12th weeks of the study. Results: Patients in the placebo and treatment groups were similar in age, duration of tamoxifen use, reported frequency and duration of hot flashes at baseline, and dropout rates. One hundred forty-nine patients completed 12 weeks of follow-up. The mean decrease in hot flash frequency was greater in the clonidine group than in the placebo group after 4 weeks of treatment (37% compared with 20% [95% CI for difference, 7% to 27%]) and 8 weeks of treatment (38% compared with 24% [CI for difference, 3% to 27%]). Patients receiving clonidine were more likely than patients receiving placebo to report difficulty sleeping (41% compared with 21%; P = 0.02). A significant difference was seen in the mean change in quality-of-life scores (0.3 points in the clonidine group compared with -0.2 points in the placebo group; P = 0.02) at 8 weeks, although the median difference was 0 in both groups. Conclusion: Oral clonidine, 0.1 mg/d, is effective against tamoxifen-induced hot flashes in postmenopausal women with breast cancer.