NEW YORK - THE lowest dose of estrogen available in a patch - 0.014 milligrams per day - is effective for easing menopausal hot flashes, a study show.

This dosage has been shown to increase bone strength, but it was not known whether such micro-dosing relieves menopausal symptoms, note Dr. Gloria A. Bachmann, of the University of Medicine and Dentistry of New Jersey, and colleagues.

To investigate further, the researchers studied 425 healthy postmenopausal women with moderate to severe hot flushes. They were given patches containing micro-dose estrogen, or low-dose estrogen (0.023 mg per day), or placebo.

After 12 weeks, the severity of hot flashes was significantly reduced in both active treatment groups compared to the placebo group, the team reports in the medical journal Obstetrics and Gynaecology.

At that point, over 41 per cent of the women receiving micro-dose estrogen were experiencing at least 75 fewer hot flashes daily, while this was the case for only 24 per cent of the women given placebo patches.

There were no differences in adverse events among women on active treatment compared with placebo.

The researchers conclude that the micro-dose estrogen patch 'may therefore be a valuable therapy for many women initiating menopausal hormone therapy, combining effective symptom relief with minimal side effects and maximum patient acceptance.' -- REUTERS