Quote from: UCBerkeleyPostop on August 02, 2012, 09:57:25 PM
Thanks for digging up that evidence, seyranna, I meant to say that I didn't have any evidence on hand that tobacco use affects HRT directly. My point was that it affects HRT at least indirectly.
And you're correct.
Nicotine effects HRT, along with most any other drug, in various complex ways. It speeds up metabolism and hepatic clearance. And some of its direct effects counteract some of the indications of HRT like osteoporosis, as well as reducing endogenous estrogen.
The question is however, if your blood results show your estradiol level is in a correct range, does nicotine exhibit any inhibiting effect on estradiols bioactive effects one past firstpass effect. The weight of evidence I have seen suggests that it does not.
If nicotine inhibited the function of serum estradiol, then nicotine would cause very significant and obvious menstrual and fertility side effects in women. Which it does not to the extent it would have to to indicate that it makes HRT useless in that sense.
So then the question instead is if nicotine inhibits or interacts with the absorption of estradiol tablets or their speed of clearance. As Seyranna's source indicates, it does. Which is why it's important to check if your serum levels are steady and sufficient. If you are doing that and they are, then smoking or no, you shouldn't be at much greater risk in terms of hormonal side effects than any other women.
In short, it won't make HRT useless. The weight of evidence I have seen indicates it may make it harder for you to establish good serum levels, but once you have those levels, it won't make much of a difference in that sense.
The other question is interaction in the form of cardiovascular and other side effects. The weight of the most current evidence would suggest that your risk factors are increased, I am not convinced that the evidence shows that it is increased in any much higher than the sum of both risk factors though.