Nitrofurantoin

Sounds like 'night-roh-few-ran-to-in'

Nitrofurantoin is an antibiotic that is used to treat and prevent urinary tract infections. Find out how to take it safely and the possible side effects.

Type of medicine Also called
  • Antibiotic (used to treat infections of the urinary tract)
  • Nifuran
  • Macrobid

What is nitrofurantoin?

Nitrofurantoin is an antibiotic that is used to treat and prevent infections of the urinary tract (UTIs), such as bladder infections. It works by killing or stopping the growth of the bugs that cause the infection. In people who get urinary tract infections often, nitrofurantoin can be used to prevent infections.

Read more about urinary tract infections in men, women, pregnancy and children.

Dose

In Aotearoa New Zealand, nitrofurantoin is available in the following forms and strengths: 

  • Nifuran: immediate release tablets (50 mg and 100 mg).
  • Macrobid: modified release capsules (100 mg).
  • Suspension (10 mg/mL).

Modified release (also called slow release) means that the capsules release the medicine slowly over several hours, so the effect of the medicine lasts longer than that of immediate release tablets or suspension. The dose of nitrofurantoin will be different for different people. Your doctor will decide on the correct dose for you, based on your condition.

An infection is usually treated with nitrofurantoin for 5–7 days. You may need to take it for longer, but your doctor will advise you on that. 

Always take your nitrofurantoin exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much nitrofurantoin to take, how often to take it, and any special instructions.

How to take nitrofurantoin

  • Take with or after food: Nitrofurantoin is best taken with or after food. If you take it when your stomach is empty it may cause a stomach upset. 
  • Modified release capsules: Must be taken twice a day. Take your dose every 12 hours, in the morning and the evening. Swallow the capsule whole, don't crush it or chew it.
  • Immediate release tablets or suspension: 
    • Space your doses evenly throughout the day.
    • For example, if you are taking them 4 times a day each dose should ideally be taken 4–6 hours apart.
    • If you are taking it once a day it should be taken every night.
  • Missed dose: If you forget to take your nitrofurantoin take it as soon as you remember, but if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose or take them close together.
  • Finish your treatment course: If you are taking nitrofurantoin for the treatment of an infection, it is best to take the antibiotic for the exact number of days your doctor has told you to. Do not stop taking it, even if you feel your infection has cleared up. Talk to your doctor first.
  • Alcohol: You can drink alcohol while taking nitrofurantoin.

Precautions before taking nitrofurantoin

  • Do you have any problems with the way your kidney or liver work?
  • Are you pregnant or breastfeeding? 
  • Do you have any breathing problems?
  • Do you have diabetes?
  • Do you have problems where your nerves cause pain or numbness (called peripheral neuropathy)?

If you answered yes to any of these questions, it’s important that you tell your doctor before you start taking nitrofurantoin. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

What are the side effects of nitrofurantoin?

Like all medicines nitrofurantoin can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Feeling sick (nausea)
  • Headache
  • Bloating and gas in the stomach
  • This is quite common when you first start taking nitrofurantoin and usually goes away with time.
  • Try taking nitrofurantoin with a meal.
  • Tell your doctor if this continues.
  • Dark yellow or brown urine
  • This is common when you are taking nitrofurantoin and is not harmful, but talk to your doctor if you are worried.
  • Cough, chest pain, shortness of breath
  • Tell your doctor.
  • Signs of problems with your liver such as yellowing of the eyes or skin, or tummy pain 
  • Tell your doctor.
  • Signs of problems with your lungs such as cough, chest pain, shortness of breath and trouble breathing, 
    joint or muscle pain, fever (high temperature) and chills.  
  • Nitrofurantoin can cause serious lung problems (called pulmonary reactions).
  • This may occur within the first month of treatment or after long-term use of nitrofurantoin (generally for 6 months or longer).
  • Tell your doctor immediately or ring Healthline 0800 611 116 if you develop symptoms of lung problems.
  • Signs of an allergic reaction such as a skin rash, itching, swelling of the lips, face, and mouth or difficulty breathing such as chest tightness, or wheezing
  • This usually occurs within the first week of starting treatment.
  • Tell your doctor immediately or ring Healthline 0800 611 116 if you develop signs of  an allergic reaction.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product

Interactions

Nitrofurantoin can interact with some medications, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting nitrofurantoin and before starting any new products.

Learn more

Nitrofurantoin NZ Formulary
Nifuran Medsafe Consumer Information Sheet, NZ

References

  1. ​Nitrofurantoin NZ Formulary 
  2. Antibiotics: choices for common infections BPAC, NZ, 2017
  3. Nitrofurantoin – not suitable in renal impairment Medsafe Prescriber Update 36(4): 51-52, December 2015
  4. Nitrofurantoin – do the benefits outweigh the risks long-term? Medsafe Prescriber Update 33(2):17-18, June 2012
  5. Nifuran Medsafe NZ
Credits: Sandra Ponen, Pharmacist. Reviewed By: Maya Patel, MPharm PGDipClinPharm, Auckland Last reviewed: 23 Dec 2021