Perhaps the doctor is trying to treat on after the other so that the medications don't cancel eachother out. I am not sure though but if he actually states that it is the same treatment then it might actually be similar treatments.... I am not sure but that is my opinion. If you want, do more research on the medications and see what they treat, if they cancel eachother out, what makes up the medications and compare them.
Also if she did the test and came out positive for those stds perhaps you should do a test yourself

not saying that you two have had sex with tons of people or anything like that... But to be on the safe side
wish you to best of luck, sorry if I wasn't that much of help... But good luck...