By John Otrompke
SAN DIEGO -- October 9, 2009 -- A novel way of administering oestrogen along with a form of biosimilar progesterone is safe and efficacious, according to a poster presented here at the 20th Annual Meeting of the North American Menopause Society (NAMS).
In the trial, researchers found that transdermal oestrogen and vaginally administered progesterone may be a more attractive therapy, but also a safe treatment for patients who request "bioidentical" therapies.
However, 17 patients did not complete the regimen or were lost to follow-up. Additionally, there was vaginal bleeding in 36.6% of patients, and 23.5% of patients who had ultrasound had a thickened endometrial lining.
"The patients were followed forward but not randomised to anything," said Wendy Wolfman, MD, Menopause Unit, Mt. Sinai Hospital, and Department of Obstetrics and Gynecology, University of Toronto, Ontario, on October 2. She explained that 50% of women who start hormone therapy drop out in the first year.
"When you give the progesterone vaginally, you can get higher local levels in the uterus, which is where you want it, and you can give lower doses as well, which is better for the breasts," said Dr. Wolfman.
For the trial, researchers conducted a retrospective chart review of 41 menopausal women, aged 45 to 65 years, with intact uteri, who had begun taking oestrogen by transdermal patch with progesterone at least 1 year previously. The progesterone was given vaginally by progesterone administered in a pill form.
"It is believed that different forms of progesterone have different effects on the breasts. We specifically chose this progesterone because we believed it was probably safer; our purpose was to really give what the body produces" said Dr. Wolfman, noting that while the therapy is approved by the Canadian government, using it vaginally was off-label and unique.
The progesterone given is usually administered orally, but in the trial, it was introduced as a pill into the vagina. "We used the same pill, but we put it into the vagina, where it melts in the mucous membrane," Dr. Wolfman said, adding that the pill melts because it is made of peanut oil. However, people allergic to peanut oil cannot take the pill, and it causes drowsiness and dizziness in 20% of those who take it.
Four women had endometrial growth on vaginal ultrasound. Two of them were outliers: one with a persistently thickened lining of 11 mm and one with an endometrial polyp and a thickness of 13 mm. Removing the 2 outliers, the average endometrial thickness on ultrasound was 3.45 mm.
Patients with a thickened endometrial lining were found to have received the therapy for only a mean duration of 13.5 months, compared with 22.2 months in those without thickening. There was no difference in rate of bleeding with respect to duration of treatment or oestrogen and progestin dose.
After 1 year of follow-up, 91.7% of patients were amenorrhoeic. All 24 patients who remained in the study had relief of their menopausal symptoms, and only 1 patient experienced breast tenderness.
In addition, 1 patient experienced dizziness, which improved after decreasing the progesterone administration to 4 days weekly from 5 days. Five patients required the addition of local oestrogen for relief of vaginal dryness.
[Presentation title: Endometrial Protection and Symptom Control of a Novel Regimen of Combination Transdermal Estrogen and Intermittent Vaginally Administered Prometrium for Relief of Menopausal Symptoms. Abstract P-28]
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