I visited a doctor to get some medicine for chlamydia. He prescribed Zithromax. The next day I went to a different doctor because I’m feeling ill. He diagnosed me with mono and prescribed Flagyl for it. Is it safe to take these two antibiotics together? Please don’t answer unless you’ve taken these together or have some credible knowledge. Thanks! 
{ 2 comments… read them below or add one }
DRUG INTERACTIONS: Alcohol should be avoided because metronidazole and alcohol together can cause severe nausea, vomiting, cramps, flushing, and headache.
There are many other medicines that can interact with Zithromax. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor. Keep a list with you of all the medicines you use and show this list to any doctor or other healthcare provider who treats you.
Doctor # 2 should have checked this, as should the pharmacist. there seems little point in taking two drugs which act in similar ways unless advised by your doctor for a specific reason. Ring and check – either with doctor or pharmacis.
The prudent thing would’ve been to mention to the second doctor that you had already been prescribed something else.
Since you’re not prudent, I see no reason to give you a reasonable answer.
In short, I don’t know if it’s safe, as I’m not a medical professional.