Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Diarrhea: If you develop diarrhea while taking tetracycline, call your doctor.
Kidney function: People with reduced kidney function should take tetracycline with caution and use an adjusted dose, as prescribed by their doctor. People with severely reduced kidney function are at risk of significant side effects with the use of this medication.
Overgrowth of organisms: The use of antibiotics may allow organisms not killed by the antibiotic to overgrow. This may cause unwanted conditions such as yeast infections.
Sensitivity to sunlight: An exaggerated sunburn reaction may occur for some people who take this medication. Watch for this if you spend time in direct sunlight or ultraviolet light and ensure that sun protection measures are taken (e.g., wear sunscreen, a hat, and long sleeve shirts). At the first sign of skin redness, stop taking the medication and see your doctor about changing your prescription.
Tooth discolouration: The use of tetracycline during tooth development (from the second trimester of pregnancy to the age of 8 years) may cause permanent discoloration of the teeth (yellow-grey-brown). Though more commonly associated with long-term use of tetracyclines, this effect has also been known to occur after taking the medication for a short time. Tetracycline should therefore not be used by children 8 years old or younger unless other medications are unlikely to be effective or can't be used.
Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: This medication passes in small amounts into breast milk. Tetracycline is not recommended for nursing women unless potential benefits outweigh the risks.