Examples

How It Works

Nitrofurantoin is an antibiotic that kills the bacteria that commonly cause urinary tract infections (UTIs). It comes in capsule or liquid form to take by mouth (orally).

Why It Is Used

Nitrofurantoin treats long-lasting (chronic) UTIs. It is also used to prevent recurrent UTIs.

Nitrofurantoin is not used to treat kidney infections because it does not reach a high enough concentration in the kidney tissue to be effective.

How Well It Works

Treatment with nitrofurantoin usually relieves symptoms of a UTI. It usually decreases the number of UTIs when taken to prevent repeat infections.

Side Effects

Common side effects are:

• Skin rashes.
• Upset stomach.
• Nausea.
• Rust-colored urine.
• Sensitivity to sunlight.

Rare but serious side effects include destruction of red blood cells, pulmonary fibrosis, and numbness of fingers and toes.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Take nitrofurantoin with food to minimize stomach upset.

Nitrofurantoin is generally not used to treat men. This is because in a man, it does not get far enough into the tissue to kill the bacteria that causes the infection.

Antacids, such as Milk of Magnesia or Mylanta, may decrease the absorption of nitrofurantoin. Do not take them within 3 to 4 hours of taking nitrofurantoin.

If you have the blood disorder glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, do not take nitrofurantoin. It can cause hemolytic anemia.

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

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.`

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.