If your symptoms do not improve within a few days (or a few weeks or months for acne patients), or if they become worse, check with your doctor.

Oral contraceptives (birth control pills) containing estrogen may not work properly if you take them while you are taking tetracyclines. Unplanned pregnancies may occur. You should use a different or additional means of birth control while you are taking tetracyclines. If you have any questions about this, check with your health care professional.

Before having surgery (including dental surgery) with a general anesthetic, tell the medical doctor or dentist in charge that you are taking a tetracycline. This does not apply to doxycycline, however.

Tetracyclines may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking TETRACYCLINE:

• Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
• Wear protective clothing, including a hat. Also, wear sunglasses.
• Apply a sun block product that has a skin protection factor (SPF) of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your health care professional.
• Apply a sun block lipstick that has an SPF of at least 15 to protect your lips.
• Do not use a sunlamp or tanning bed or booth.

You may still be more sensitive to sunlight or sunlamps for 2 weeks to several months or more after stopping TETRACYCLINE. If you have a severe reaction, check with your doctor.

For patients taking minocycline:

• Minocycline may also cause some people to become dizzy, lightheaded, or unsteady. Make sure you know how you react to TETRACYCLINE before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert. If these reactions are especially bothersome, check with your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. In some infants and children, tetracyclines may cause the teeth to become discolored. Even though this may not happen right away, check with your doctor as soon as possible if you notice this effect or if you have any questions about it.

• For all tetracyclines
  • More common
    • Increased sensitivity of skin to sunlight (rare with minocycline)  
    
    
  • Rare
    • Abdominal pain;  bulging fontanel (soft spot on head) of infants;  headache;  loss of appetite;  nausea and vomiting ;  visual changes;  yellowing skin 
    
    

• For demeclocycline only
  • Less common
    • Greatly increased frequency of urination or amount of urine;  increased thirst;  unusual tiredness or weakness 
    
    

• For minocycline only
  • Less common
    • Pigmentation (darker color or discoloration) of skin and mucous membranes 
    
    

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• For all tetracyclines
  • More common
    • Cramps or burning of the stomach;  diarrhea  
    
    
  • Less common
    • Itching of the rectal or genital (sex organ) areas;  sore mouth or tongue 
    
    

• For minocycline only
  • More common
    • Dizziness, light-headedness, or unsteadiness 
    
    

In some patients tetracyclines may cause the tongue to become darkened or discolored. This effect is only temporary and will go away when you stop taking TETRACYCLINE.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, tetracyclines are used in certain patients with the following medical conditions:

• Gonococcal arthritis
• Leprosy (for minocycline)
• Lyme disease (for doxycycline and tetracycline)
• Malaria treatment (for doxycycline and tetracycline)
• Nocardiosis (a type of bacterial infection) (for doxycycline and minocycline)
• Ocular rosacea (a type of eye infection) (for doxycycline and tetracycline)
• Pneumothorax (a pocket of air in the space surrounding the lungs) (for doxycycline and tetracycline)
• Rheumatoid arthritis (for minocycline)
• Shigellosis (a type of intestinal infection) (for doxycycline and tetracycline)
• Syndrome of inappropriate antidiuretic hormone (SIADH) (for demeclocycline)

For patients taking TETRACYCLINE for SIADH:

• Some doctors may prescribe demeclocycline for certain patients who retain (keep) more body water than usual. Although demeclocycline works like a diuretic (water pill) in these patients, it will not work that way in other patients who may need a diuretic.

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.