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If you have mild to moderate Crohn's, your doctor may give you antibiotics to help keep your disease under control.

You may need to take the antibiotics even after you feel better to keep your symptoms from getting worse again.

There are two ways these drugs treat the inflammation in your gut from Crohn's. Researchers believe they might help control symptoms by reducing bacteria levels in your intestine and by curbing the intestine's immune system.

You'll also get them to treat specific infections and complications.

Antibiotics for Crohn's Complications

Abscesses. These are pockets of pus that, in Crohn’s, often form near the anus.

Fistulas. These are abnormal tunnels that go from one part of your intestine to another or to nearby areas, such as the bladder, vagina, anus, or skin.

Pouchitis. For some people, Crohn’s disease is so severe that they need an operation to have their colon removed. The surgeon makes an internal pouch to hold solid waste before it leaves your body. If this area becomes inflamed -- known as "pouchitis" -- you'll need antibiotics for treatment.

Antibiotics for Crohn's Disease

The most common ones used for Crohn's are:

  • Ciprofloxacin (Cipro)
  • Metronidazole (Flagyl)

Some people need to get antibiotics through a vein (IV).

Side Effects of Antibiotics

Side effects of metronidazole may include:

  • Nausea
  • Loss of appetite
  • Metallic taste
  • Diarrhea
  • Dizziness
  • Headaches
  • Dark urine

Side effects are more common at higher doses.

With metronidazole, you may also have numbness or tingling in your hands. If you do, you'll need to stop taking it. Although this side effect is rare, sometimes it doesn't go away. Seizures are another rare, serious side effect.

Avoid alcohol if you're taking metronidazole. It can interact with the drug to cause a rare but severe reaction. The symptoms are nausea, vomiting, and shortness of breath.

These side effects of ciprofloxacin are rare, but may include:

  • Headache and severe dizziness
  • Nausea, stomach pain, and diarrhea
  • Sensitivity to sun
  • Rupture of a tendon (very rare)
  • Confusion
  • Depression
  • Hallucinations
  • Fast heartbeat

You're also at greater risk for a severe type of colitis. If you get it, you'll need treatment with another type of antibiotic.

Do not take ciprofloxacin within a couple of hours of taking:

  • Antacids
  • Vitamin or mineral supplements that contain calcium, iron, or zinc

This combination can make the antibiotic less effective.

Other Precautions

No matter which antibiotic you're taking:

  • Let your doctor know if you're pregnant before starting the medication.
  • Wear sunscreen during daylight hours.
  • Know that antibiotics can make birth control pills less effective.
  • Be aware that antibiotics can make bleeding more likely if you're also taking anticoagulants (drugs that curb blood clots).