According to MedlinePlus, a Z-Pak contains azithromycin tablets and is used to treat certain bacterial infections, including bronchitis, pneumonia, sexually transmitted diseases, and infections of the ears, lungs, sinuses, skin, throat and reproductive organs. It also prevents and treats a lung infection called Mycobacterium avium complex, which often affects people with HIV. Occasionally, azithromycin is used treat H. pylori infection, travelers' diarrhea, Legionnaires' disease, pertussis and babesiosis.
Before taking a Z-Pak, MedlinePlus advises the patient to inform his doctor of his medication allergies and any current medications, vitamins and supplements he is taking so that interactions can be checked.
It is also important for the doctor to know if the patient has a personal or family history of a heart condition called prolonged QT interval or fast, slow or irregular heartbeats. The patient is also advised to report if he has a history of low magnesium or potassium levels in his blood or if he has a blood infection, AIDS or HIV, heart failure, cystic fibrosis, myasthenia gravis, kidney disease or liver disease. A woman should inform her doctor if she is pregnant, may become pregnant, or is breastfeeding.
MedlinePlus states that some people experience side effects while taking azithromycin, including nausea, diarrhea, vomiting, headache and stomach pain. A doctor needs to know about these side effects only if they are severe or persistent.