Expert: Catherine - 1/16/2006

Question
I have been taking evista for about 9 months and just read that there might be an interaction with Levothroid (which I also take).. Is there?

Also, I would like to know if it is OK to take a product like Remifemin (over-the-counter menopause relief) with Evista to stop the hot flashes.  I previously took Remifemin for hot flashes before I was on Evista, and it worked.

Answer
The interaction is related to the time of day you take the medications, the Evista can make the thyroid medication not be absorbed as well.  To avoid this, you should take the thyroid in the morning and the Evista at night, ideally taking them as close to 12 hours apart as possible.  It's a bigger problem if you're on warfarin or another drug that depends on the levels of thyroid medication in your system to work than if you're only taking those two drugs.  If you haven't been noticing any problems with your thyroid levels so far or symptoms that might indicate it's out of control, and you're not on other medications that are affected by thyroid, then you're most likely getting enough absorbed anyhow, but if you're not already taking them at different times of day, switching to doing that would still be a good idea.

The active ingredient in Remifemin, black cohosh, doesn't appear to act on the estrogen system in the same way, and so doesn't seem to interact with Evista.  Of course, if you notice any new side effects when taking them together, you should go off the Remifemin - it could be an interaction that's not common, or it could just be from that particular batch of the black cohosh supplement, though if you stick with the same brand you've had good results with in the past, this should be less likely than if you switch to some unknown brand of black cohosh.