Risk to switch from Brand to Generic Tri-Legest Fe

I have been on Estrostep Fe for 5 years.  Our insurance is now requiring us to switch to the generic for Tri-Legest Fe.  I asked my GYN about switching a few years ago and she advised that there is a 10% risk of a reaction to my cycle.  

Also I seem to recall a friend of my switching to a generic of Estrostep and it messed up her cycle and she had many problems with it.  She said she switch to a generic.  Could that be Tilia Fe which I believe is a little different but close to Estrostep.

My local Pharmacists advised that there is no chemical difference between the Brand (Estrostep Fe) and Generic (Tri-Legest Fe) except in the shape, color or inactive ingredients. They never heard of anyone having an issue switching between the Brand to the Generic.  

I feel that either the GYN is pushing the Brand due to kick backs, I am  confusing the issues or lack of with switching to another medication, the Insurance is pushing a cheaper brand regardless of risks, or the Pharmacists does not know the reactions.  I do not want to go through the 3 month adjustment period to change to the generic as everything is great now on Estrostep. If there is zero risk to my cycle by switching to Tri-Legest FE, I would really like to save the cost difference switching to the generic.   Please advise and provide the truth to this confusing topic.  Thanks for your help.

[Sandra Y, RPh]

Generically available prescription medications by Federal Law are required to be tested before they can be approved for availability on the market to be bioequivalent (same amount of drug concentration in the body) to the Brand name medication. The Pharmacist you spoke to was correct in saying the difference between Brand and Generics are usually the shape of the pill or package, color, and inactive ingredients (which should have no effect on the efficacy of the drug). There are very few medications that there is caution when switching from brand to generic equivalents and usually are medications used to treat serious conditions such as organ transplant rejection medications and thyroid hormone medications due to the effect a small variation could have on the patients’ body and success of treatment. The products mentioned the Brand Estrostep Fe, Tri-Legest Fe, and Tilia Fe are all considered “Triphasic” oral contraceptive formulations and have varying strengths of hormone for different days of the cycle (which is supposed to more closely mimic the normal female menstrual cycle). All 3 products contain ethinyl estradiol and norethindrone (both synthetic female hormones; estrogen and progestin) and on days 1-5 contain Ethinyl estradiol 0.02mg and Norethindrone acetate 1mg, days 6-12 contain Ethinyl estradiol 0.03mg and Norethindrone acetate 1mg, days 13-21 contain Ethinyl estradiol 0.035mg and Norethindrone acetate 1mg, and days 22-28 contain no hormones but have ferrous fumarate 75mg (iron supplementation during menses). To address your concern of “zero” risk, there is no way to tell if your body will react the same to switching to a generic however there is the exact same amount (as written out above) of hormone agent in each of the three mentioned products and your body should not have an issue if you choose to switch.