Metformin improves menstrual cycle regularity and lowers body mass index, testosterone, and luteinizing hormone within 6 months of treatment in women with polycystic ovary syndrome who are normal weight or overweight as per a new study in January 9 issue of Journal of Clinical Endocrinology & Metabolism.

PCOS is evaluated in adolescent girls with an abnormal degree of hirsutism or menstrual abnormality (persistently irregular menses or severe anovulatory abnormal uterine bleeding) or in girls with multiple minor characteristics suggestive of PCOS, such as obesity or focal hirsutism, particularly if associated with menstrual abnormalities.

Clinical suspicion is followed by laboratory testing for androgen excess, measuring total or free testosterone.

If serum free testosterone levels are normal (in the absence of oral contraceptives), the diagnosis of PCOS is unlikely.

However, the possibility of PCOS in an adolescent should not be fully dismissed until menses normalize and androgen levels are persistently normal.

If serum levels of total and free testosterone are elevated, a focused history and physical examination is done to exclude other hyperandrogenic disorders that includes ultrasonography [to exclude the rare but serious adrenal or ovarian tumor and ovarian pathology not related to PCOS] and a screening battery of endocrine tests at this stage.

Determining whether the ovaries are polycystic is not helpful for the diagnosis of PCOS because of the high frequency of polycystic-appearing ovaries in adolescents with or without PCOS.

If the results of the endocrine screening panel are normal, the diagnosis of PCOS is confirmed.

Any abnormal results suggest that the hyperandrogenism is caused by a disorder other than PCOS.

Overall, 50 to 70 percent of women with PCOS demonstrate clinically measurable insulin resistance.

Metformin is available in a generic form as 500, 850, and 1000 mg tablets. The target dose is 1500 to 2000 mg daily; clinically significant responses are not regularly observed at doses less than 1000 mg daily.

One can start with 500 mg taken with a meal to reduce gastrointestinal side effects. If tolerated, the dose can be increased to 500 mg at both lunch and dinner and then to 500 mg at breakfast, lunch, and dinner. One to two weeks should elapse between increases in dose.

Extended-release tablets are also available, although patients who are doing well on short-acting preparations should continue them as there is little, if any, additional benefit documented with the long-acting preparation.

However, extended-release metformin may be associated with fewer side effects. The entire daily dose may be given at dinner time. The dose is initially 500 mg with dinner and is escalated gradually to a maximum of 2000 mg.

Where the traditional formulations are not tolerated, it is occasionally helpful to have the patient try either the liquid or slow-release formulation before abandoning metformin therapy.

Metformin also reduces intestinal absorption of vitamin B12 in up to 30 percent of patients and lowers serum vitamin B12 concentrations in 5 to 10 percent.

Metformin should not be prescribed for women with other conditions that increase the risk of lactic acidosis, such as renal insufficiency, congestive heart failure, or sepsis.