Metformin’s benefit not limited to obese patients: increases ovulation, decreases testosterone. (Polycystic Ovary Syndrome).
Author/s: Timothy F. Kirn
Issue: August 1, 2002
SAN FRANCISCO — Metformin significantly increases the frequency of ovulation and decreases circulating testosterone in women with polycystic ovary syndrome who are not obese and have normal indices of insulin sensitivity, Dr. Jean-Patrice Baillargeon said at the annual meeting of the Endocrine Society.
Previous studies have shown only that insulin-sensitizing drugs are useful in polycystic ovary syndrome (PCOS) patients generally; many of these patients are insulin resistant and/or overweight, said Dr. Baillargeon of the Medical College of Virginia, Richmond.
Moreover, the current study found that metformin treatment significantly reduced insulin levels, even though the study patients were not apparently insulin resistant. This finding suggests some insulin resistance in all women with PCOS, Dr. Baillargeon said.
In the study 100 women with PCOS who were not obese and had normal indices of insulin sensitivity were randomized to receive 6 months of treatment with either metformin, rosiglitazone, metformin plus rosiglitazone, or placebo.
The mean number of ovuladons over the 6 months–defined as a serum progesterone level above 4.0 ng/mL followed by menstrual bleeding–was 0.4 for the patients assigned to placebo, 3.3 for those on metformin, 2.4 for those on rosiglitazone, and 3.4 for those on the combination.
It appeared that the drugs needed a few months to take effect, Dr. Baillargeon said. But by 5 months, all of those on the combination treatment and almost all of those on metformin alone had become ovulatory.
With metformin alone and in combination, 93% of the patients ovulated in both the fifth and sixth months. That percentage shrunk to 59% to patients on rosiglitazone alone. None of the patients on placebo ovulated during both the fifth and sixth months.
Rosiglitazone did not result in a significant decrease in fasting insulin, but metformin did.
Free testosterone dropped 1.2 picomole/L in the placebo group, 12.8 picomole/L in the metformin group, 12.3 picomole/L in the rosiglitazone group, and 21.9 picomole/L in the combination treatment group.
Moreover, unlike metformin, rosiglitazone was associated with weight gain, an average of 1.2 kg.
The study showed that metformin was superior to rosiglitazone but that the “combination of metformin plus rosiglitazone did not add any benefit above metformin alone,” Dr. Baillargeon said.
The dosages used in the study were 850 mg twice daily for metformin and 4 mg twice daily for rosiglitazone. The combined therapy involved the same dosages.
COPYRIGHT 2002 International Medical News Group
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