I am on birth control (YAZ). My birth control will be effective or not, if I will be taking phentermine cause ?

Thanks for help!

Birth control is always very sensitive, especially hormonally based birth control. Even if a medicine is considered safe, which phentermine is, there are always other factors to bear in mind. If you tend to respond normally to medicines, then you would fall into the range of "average reaction," which means that your birth control should be effective. If you seem to have great difficulty taking medications, often need to switch to find medicine that works for you, or have unusual reactions, your body does not register "average reactions."
For most people, this medication does not effect the usefulness of birth control.

many women go for birth control pills with phentermine but they do not find any side effects,
but sometimes reaction of certain medication very from person to person, it also depends upon doses you take, the doses has to be taken under medical expert.
It also depends upon you lifestyle.