Examples
| Brand Name | Chemical Name |
|---|---|
How It Works
Tetracyclines are antibiotics that kill the bacteria that commonly cause urinary tract infections (UTIs). Tetracyclines come as tablets or pills to take by mouth (orally).
Why It Is Used
Tetracyclines treat uncomplicated UTIs, which are ones that are not caused by an obstruction or structural problem or some other medical condition that affects urinary function, such as diabetes.
Do not take tetracyclines during pregnancy or when breast-feeding, because they can harm the baby.1
How Well It Works
Tetracyclines are well absorbed from the stomach and effectively treat a broad range of bacteria. You should feel relief of symptoms of a UTI in 2 to 3 days after starting tetracycline treatment.
Side Effects
Common side effects of tetracyclines include:
- Increased sensitivity to sun.
- Stomach upset.
- Nausea.
- Vomiting.
- Dizziness.
- A sore mouth.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
Do not take tetracyclines during pregnancy or when breast-feeding, because they can harm the baby.
Children younger than 8 should not take tetracyclines.
Tetracyclines are less expensive than some other antibiotics, but they may not be effective against certain strains of bacteria.
Do not take tetracyclines with dairy products such as milk or cheese, because this can affect the way your body absorbs the drugs. They should be taken on an empty stomach. But if you need to eat something to help with stomach upset, eat a cracker or other nondairy snack when taking tetracycline.
Avoid calcium antacids, magnesium-containing medicines, and iron supplements within 3 hours of taking tetracyclines, because they may make tetracycline less effective.
Tetracyclines may affect the way birth control pills (oral contraceptives) work. Talk to your doctor about using another form of birth control while you are taking tetracyclines, until your next period.
Tetracyclines may increase your sensitivity to the sun, making it easier to get a sunburn while you are taking these drugs.
- Avoid direct sunlight and sunlamps while you are taking these drugs and for 5 days after you have stopped taking the drugs.
- Most sunscreens do not block enough of the ultraviolet rays to avoid a reaction to the sun. If you cannot avoid direct sunlight, cover as much of your body as you can with clothing.
Antibiotic resistance
Be sure to take all of the medication your doctor gives you, even if you are feeling better. If you do not take all of your antibiotics as prescribed, the infection may return. Not taking the full course of antibiotics also encourages the development of bacteria that are resistant to antibiotics. This not only makes antibiotics less effective but also makes bacterial infections more difficult to treat.
Antibiotic resistance among bacteria that cause UTIs has increased steadily in recent decades. You and your doctor may have to try different antibiotics, and different combinations of antibiotics, to find the right medication that will kill the bacteria causing your UTI. Before you start a new antibiotic, your doctor may use results of urine tests to help select a medication.
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References
Citations
| Author: | Kathe Gallagher, MSW | Last Updated: June 15, 2007 |
| Medical Review: | E. Gregory Thompson, MD - Internal Medicine Philip Belitsky, MD, FRCSC - Urology | |
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