Nitrofurantoin

💊 What is Nitrofurantoin used for?

• •Urinary tract infections (UTIs) caused by susceptible strains of Escherichia coli, enterococci, Staphylococcus aureus, and certain susceptible strains of Klebsiella and Enterobacter species
• •Long-term suppressive therapy, which the label describes for adults and for children, to help prevent repeat infections

How it works

How it is usually taken

• •The label says to take this medicine with food, because food improves absorption and, for some people, tolerance. The label says to complete the full course of therapy, even if you feel better early, and to contact your prescriber if unusual symptoms occur. The prescriber sets the dose and length of treatment based on the infection, and the label links treatment length to urine test results. The label says not to use antacids that contain magnesium trisilicate while taking it.

Comes as

• •Capsules: 25 mg, 50 mg, and 100 mg (macrocrystals)

⚠️ Nitrofurantoin side effects

🛑 Who should not take Nitrofurantoin, and who should be careful

The label says not to take it if

• 🚨You have very low or no urine output (anuria or oliguria), or significant kidney impairment as shown by kidney function tests
• 🚨You are pregnant at full term, in labor, or when labor is about to start
• 🚨The baby is under one month of age (the label says this is a contraindication for newborns)
• 🚨You have had cholestatic jaundice or liver dysfunction in the past that was caused by nitrofurantoin
• 🚨You have a known allergy (hypersensitivity) to nitrofurantoin

Tell your doctor before taking it if

• •Tell your prescriber about any kidney problems, since the label says significant kidney impairment raises the risk of toxicity.
• •Tell your prescriber if you have diabetes, anemia, vitamin B deficiency, electrolyte imbalance, or a debilitating disease, because the label says these can increase the risk of nerve damage.
• •Tell your prescriber if you have a glucose-6-phosphate dehydrogenase deficiency, because the label links this to hemolytic anemia.
• •Tell your prescriber about any past lung, liver, or other reaction to nitrofurantoin.
• •If you are pregnant, planning a pregnancy, or breastfeeding, talk with your prescriber, since the label gives specific guidance for these situations.
• •If you need long-term treatment, the label says your doctor should monitor your lungs, liver, and kidney function over time.

🔀 Nitrofurantoin with other medicines, food and alcohol

The label says to discuss these with your doctor or pharmacist

• •Antacids containing magnesium trisilicate: these reduce how much and how quickly nitrofurantoin is absorbed. The label advises not to use them while taking this medicine.
• •Probenecid and sulfinpyrazone (uricosuric drugs): these can slow how the kidneys remove nitrofurantoin, which may increase toxicity and lower how well it treats urinary infections.

Alcohol and food

Take this medicine with food, as the label recommends. The label does not give any information about alcohol.

🤰 Nitrofurantoin in pregnancy and breastfeeding

Pregnancy

The label lists this medicine as Pregnancy Category B. Animal studies showed no harm to the fetus at certain doses, but the label says there are no adequate, well-controlled studies in pregnant women. The label says it should be used during pregnancy only if clearly needed. It also states this medicine is contraindicated at full term, during labor and delivery, or when labor is imminent. One mouse study linked the drug to lung tumors in offspring, and the label says the relevance to humans is unknown.

Breastfeeding

The label says nitrofurantoin has been found in human breast milk in trace amounts. Because of the potential for serious reactions in nursing infants under one month old, the label says a decision should be made whether to stop nursing or stop the drug, weighing how important the drug is to the mother.

🗓️ Storage, missed doses and taking too much

Storage

The label says to store at 25°C (77°F), with brief excursions permitted between 15°C and 30°C (59°F and 86°F). Keep it in a tight, light-resistant container with a child-resistant closure.

If a dose is missed

The label does not say.

If too much is taken

The label says that acute overdoses have rarely caused symptoms other than vomiting. It recommends inducing vomiting and keeping fluid intake high to help the body flush out the drug. There is no specific antidote, and the drug can be removed by dialysis. Seek medical help right away after any suspected overdose.

🗒️ Questions to ask about Nitrofurantoin

• Is my infection likely caused by bacteria that this medicine can treat?
• How long will I need to take this medicine, and should I return for urine tests?
• Should I take this with food, and which antacids should I avoid?
• What signs of lung, liver, or nerve problems should I watch for while taking it?
• Does my kidney function, blood count, or other health condition affect whether this medicine is right for me?
• What should I do if I develop diarrhea after finishing the medicine?

❓ Nitrofurantoin: frequently asked questions