What is the most important information I should know about PROTONIX?

You should take PROTONIX exactly as prescribed, at the lowest dose possible and for the shortest time needed.
PROTONIX may help your acid-related symptoms, but you could still have serious stomach problems. Talk with your doctor.
PROTONIX can cause serious side effects, including:

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A type of kidney problem (acute tubulointerstitial nephritis). Some people who take proton pump inhibitor (PPI) medicines, including PROTONIX, may develop a kidney problem called acute tubulointerstitial nephritis that can happen at any time during treatment with PROTONIX. Call your doctor right away if you have a decrease in the amount that you urinate or if you have blood in your urine.

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Diarrhea caused by an infection (Clostridium difficile) in your intestines. Call your doctor right away if you have watery stools or stomach pain that does not go away. You may or may not have a fever.

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Bone fractures (hip, wrist, or spine). Bone fractures in the hip, wrist, or spine may happen in people who take multiple daily doses of PPI medicines and for a long period of time (a year or longer). Tell your doctor if you have a bone fracture, especially in the hip, wrist, or spine.

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Certain types of lupus erythematosus. Lupus erythematosus is an autoimmune disorder (the body's immune cells attack other cells or organs in the body). Some people who take PPI medicines, including PROTONIX, may develop certain types of lupus erythematosus or have worsening of the lupus they already have. Call your doctor right away if you have new or worsening joint pain or a rash on your cheeks or arms that gets worse in the sun.

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Low magnesium and other mineral levels in your body can happen in people who have taken PROTONIX for at least 3 months. Tell your doctor if you have symptoms of low magnesium levels, including seizures, dizziness, irregular heartbeat, jitteriness, muscle aches or weakness, and spasms of hands, feet or voice.

Talk to your doctor about your risk of these serious side effects.
PROTONIX can have other serious side effects. See "What are the possible side effects of PROTONIX?"