ADHD. If the most effective treatments for this disorder—stimulant drugs such as methylphenidate and dextroamphetamine—don't improve your child's behavior, clonidine may help control some symptoms such as hyperactivity and impulsiveness. A 2008 randomized, placebo-controlled trial involving 122 children with ADHD found that the drug offered some benefit in the home setting but was reported to be less effective in the classroom based on parent and teacher surveys to assess the child's ADHD symptoms.



Studies suggest that clonidine may be more valuable as an adjunct medication to treat secondary ADHD symptoms and the side effects of stimulants. Those may include aggression, jittery behavior, irritability, tics, and insomnia. Clonidine is among the most commonly prescribed drugs to treat insomnia for children with ADHD, according to a survey of more than 1,200 child psychiatrists. However, the American Academy of Sleep Medicine advises first trying behavioral strategies for pediatric insomnia and using medication sparingly. Consumer Reports medical advisors urge people to avoid taking medication to treat the side effects of another drug unless that drug is essential.



Hot flashes. Estrogen-replacement therapy is the most effective treatment for this menopausal symptom, but it increases the risk of stroke, blood clots, and breast cancer. Consequently it's not recommended for many women, particularly those who have had breast cancer.



Studies suggest that clonidine modestly improves the severity and frequency of hot flashes in some women, and it's a sensible choice for those who also suffer from high blood pressure. It may also be useful for breast-cancer survivors who are taking tamoxifen, a drug that reduces the chance that cancer will recur but also induces hot flashes. However, a 2007 randomized trial by the European Society for Medical Oncology found that the antidepressant drug venlafaxine was more effective than clonidine for reducing hot flashes in breast-cancer patients.