Web sites often list interactions in a general way.
There are two types of interaction.
1) One is where one drug depletes another (as with your bcp)
2) The other is where one drug increases the amounts of another drug--- as in some liver enzyme blocking actions. This type is a true interaction, but different than #1.
It is not really an interaction which you have from the bc's. It is a side effect of those hormones on the body, with reduces the B-complex metabolism(including B12). An interaction in the purest sense would be B12 conflicting with bc's, as in reducing the bc concentration in the blood leading to failure of the bc's to prevent a pregnancy. But this is not what the "interaction" is in reality, which is the negative effect bc's have on B12's ability to work in the body properly.
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All truths are easy to understand once they are discovered; the point is to discover them.-- Galileo Galilei
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Weezie looking at petunias 8.25.2017
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