Tetracycline is a medicine that belongs to the group of tetracycline antibiotics and can be used to treat a wide range of conditions caused by bacteria. This medicine is not intended for viral infections, such as cold or flu and is not going to be efficient for them. Before your health care provider prescribes tetracycline you will need to inform him of any of the following medical conditions you have: diabetes, kidney or liver disease, allergies, or asthma. The medical conditions mentioned above can influence the dose you are prescribed and you may even be recommended to have some lab tests done. All that is necessary to make sure your treatment is going to be efficient and safe. If you missed a dose and it's almost time to take another one, it's best to skip the dose missed and avoid taking a double dose. Taking a double dose is not going to make your treatment more efficient and can cause more serious side effects. You need to be very careful when taking tetracycline and avoid combining it with other medications such as antacid, tretinoin, blood thinners, cholesterol-lowering medications, minerals, isotretinoin, products that contain bismuth subsalicylate, penicillin antibiotic, and mineral supplements. Make sure you wait for at least 2 hours before you take acids, laxatives, iron products, or calcium supplements, as this way both medications will be most efficient for you. Never give this medicine to children younger than 8, as it may cause permanent staining of their teeth later in life. Pregnant or breastfeeding women are not supposed to be taking tetracycline as it has been classified as FDA pregnancy D. It can be harmful to unborn and nursing babies affecting their bone and tooth development and causing a number of other health problems if taken by a pregnant or breastfeeding woman. The following side effects are possible when tetracycline is used: itching of the rectum, changes in skin color, upset stomach, diarrhea, redness of the skin, and sore mouth. These symptoms are not expected to get more serious and in most cases they disappear on their own. Other more serious side effects are also possible and may include the following ones: body aches, red skin rash, blurred vision, jaundice, severe pain in your upper stomach, loss of appetite, severe blistering, fever, dizziness, confusion or weakness, chills, urinating less than usual, dark colored urine, easy bruising or bleeding, and severe headache. If you have a reason to believe you have taken too much of tetracycline and get any symptoms that seem serious, seek emergency medical assistance. Wear protective clothes when staying outside for a long time, as tetracycline has been reported to cause increased light sensitivity. You are never supposed to share this medication with other people to whom it was not prescribed. Keep tetracycline out of the reach of children and other people that may want to gain access to it. Any questions you have are supposed to be directed to your doctor or pharmacist.