I finished taking Zithromax for a chest infection a week ago. I am 11 days late on my period and I had protected sex 20 days ago. I only use condoms. Would the Zithromax throw off my period, or cause me to miss altogether?

First off, I'm not an expert or medical doctor. That said, it seems extremely unlikely an antibiotic like Azithromyocin (Zithromax is the brand name) would cause a missed period. Cursory net research gives no indication of such a side effect. Check the link below, for example. I've never heard of a widely used antibiotic causing a missed period, and cannot think of a biological mechanism by which it would happen. There are a few antibiotics that can interfere with birth control, but I don't think Zithromax is one of them.

I can't find any side effect of Zithromax that causes irregularities in the menstrual cycle. I've taken Zithromax quite a few times (because I'm allergic to penicillins and some cephalasporins) and it's never had that effect on me either.



11 days is late enough that I'd take a pregnancy test, especially if you are usually very regular.

I'm not saying that it can't be possible, but I've never heard of it happening. I've been on Zithromax before, and I have never missed a cycle. I would take a pregnancy test, because condoms can have little holes in them, and they are not 100% accurate. But as far as the meds go, I don't think that's the problem.

NO.



I have taken Zithromax before a couple of times. It did not effect my periods any.



See your Gyn. Your period could be late due to stress or there is a small chance you could be pregnant (condoms can rip).

Rarely. I would check a pregnancy test.

It shouldn't but you should know if you are female and on birth control pills, antibiotics can weaken the effect of the pills. so if you are sexually active you might want to take a pregnancy test.

it shouldn't throw off your period, in fact it should still be normal.

No it won't make you miss a period, but if you look at the packaging it does cause birth control pills to loose their effectiveness. So be careful if you ever take the pill and any antibiotic. Take a pregnancy test! You might be late, just because you weren't your normal self with the chest infection. It could have caused strain on your entire body!

I can't give you a definite answer from a medical point but I can tell you from personal experience. I was taking a Z-PAC for an infection and missed my period for a month. I completely skipped it. I wasn't worried about being pregnant because I wasn't sexually active at the time but it was still scary. When I asked my doctor about it he said that some antibiotics can throw your period off. It took me a couple of months to get back on my regular cycle. I don't think that you have anything to be worried about - especially if you have been using protection. But I'd still take a pregnancy test.