Tetracycline is often prescribed for patients suffering from any of the wide range of infections caused by bacteria, including urinary tract infections, gonorrhea, chlamydia, acne and other conditions. Your health care provider needs to see the full list of medicines you are currently taking, including penicillin antibiotics (dicloxacillin, carbenicillin, penicillin, oxacillin and amoxicillin), bismuth subsalicylate products, isotretinoin, any supplements, cholesterol-lowering medications, blood thinners, tretinoin, minerals (zinc, iron, calcium, magnesium), antacids. Tetracycline can cause harm to an unborn baby, including teeth discoloration later in life. This drug can be given to children younger than 8 only if your doctor thinks it's absolutely necessary. Some of the mild side effects you may experience when you start taking this drug include mild nausea, diarrhea, vomiting, stomach upset, vaginal itching or vaginal discharge, sore mouth or lips and swollen tongue. Report any of the following serious side effects to your health care provider as soon as possible: pale skin, yellowed skin, severe stomach pain, peeling, blistering and red skin rash, loss of appetite, easy bleeding and bruising, trouble breathing, blurred vision, flu-like symptoms, fever, chills and body aches, as well as unusual weakness, fever and confusion. Tetracycline makes your skin more sensitive, so make sure you use a reliable sunscreen and wear protective clothing to avoid getting sunburn.