What is antibiotic-associated diarrhea?

Antibiotic-associated diarrhea is a side effect of taking antibiotics. Most often the diarrhea is mild and goes away when you stop taking the antibiotic. Much less common is a very serious type of antibiotic-associated diarrhea called pseudomembranous colitis.

How does it occur?

Antibiotics can upset the natural balance of bacteria in the intestines. When potentially harmful bacteria multiply beyond normal levels in the intestines, diarrhea and other symptoms may result.

Almost any antibiotic can cause an imbalance of bacteria in the body. Some of the most common ones include ampicillin and clindamycin.

When there is an overgrowth of the bacteria called Clostridium difficile, toxins may be produced that cause severe abdominal pain, fever, and, rarely, bloody diarrhea. This condition is called pseudomembranous colitis.

What are the symptoms?

The symptoms of antibiotic-associated diarrhea are usually mild, consisting of loose or frequent bowel movements. Bowel movements usually return to normal within a few days after you stop taking the antibiotic.

Symptoms of pseudomembranous colitis are more severe and may include:

• watery, profuse diarrhea (sometimes bloody)
• abdominal pain and cramping
• nausea
• dehydration
• fever.

How is it diagnosed?

If you have been taking antibiotics recently, your doctor will suspect that the diarrhea is a side effect of the antibiotic. If your case is mild, you may not need any lab tests.

If you have a more severe case, the doctor may check for toxins in your stool. Sometimes the doctor will examine the lining of your rectum and lower bowel to look for changes that are typical of pseudomembranous colitis.

How is it treated?

If your symptoms are mild, your health care provider may recommend that you:

• Stop taking the antibiotic.
• Change your diet temporarily.

If your symptoms are more severe, you may need bed rest, intravenous (IV) fluids, and yet another antibiotic to treat Clostridium bacteria.

How long do the effects last?

In mild cases, diarrhea may last up to 14 days after you stop taking the antibiotic. More severe symptoms may not go away until several weeks after you begin treatment.

Occasionally, the symptoms will return in spite of treatment.

How can I take care of myself?

Follow your doctor's instructions regarding rest, activity, medication, and diet. Your doctor will probably suggest that you:

• Drink clear liquids (for example, water, apple juice, tea, bouillon, flat ginger ale).
• Eat only bland foods in small quantities (for example, soda crackers, toast, plain pasta, noodles, bananas, baked or broiled potatoes).
• Avoid foods and drinks that sometimes cause diarrhea, such as caffeine, alcohol, milk and milk products, large amounts of fruit or fruit juices (except bananas), and foods seasoned with hot peppers.
• After a few days, you may return to normal eating, carefully adding back any of the foods that sometimes cause diarrhea.

If you have cramps or abdominal pain, it may help to put a hot water bottle or electric heating pad (set on low) on your abdomen.

If your doctor prescribes a new antibiotic, take all of the medicine as prescribed.

Call your doctor if:

• Your pain persists or worsens.
• Your diarrhea or other symptoms worsen.

What can I do to help prevent antibiotic-associated diarrhea?

• Take antibiotics only when you and your health care provider feel they are necessary.
• Take antibiotics exactly as they are prescribed. Do not increase the dose, the time between your doses, or the number of days you take the medication unless instructed to do so by your doctor.
• When possible, avoid taking antibiotics that cause you to have these symptoms.