The response times were fast, they made sure I was satisfied and more importantly they believed me when I told them about the snafu with my delivery going missing.
Jefferson T
Used for
Treats urinary tract infections (UTIs) in women and men.
How to use it*
Take 100mg twice daily for 7 days, with a full glass of water or food to avoid stomach irritation.
How long to work
Relief typically within 1-2 days; complete the full 7-day course even if symptoms improve earlier.
Common side effects*
Nausea, headache, diarrhea, and stomach upset.
Who should not take it*
Avoid during pregnancy (especially near term), if allergic to Nitrofurantoin, or if you have severe kidney problems.
Interactions*
Avoid with antacids containing magnesium; avoid alcohol as it can make UTI symptoms worse.
Generic/branded
Generic: Nitrofurantoin.
Brand: Macrobid.
* Always consult the patient leaflet for comprehensive information.
Nitrofurantoin belongs to a group of medicines called antibiotics. It is used to treat bacterial infections, such as UTIs.
Nitrofurantoin works by killing the bacteria that is causing the infection. When you take this medicine orally, most of it gets filtered out of the blood and into your urine. This means that this medicine is concentrated where the causative bacteria are. Once there, the medicine enters the bacterial cells and damages their DNA, stopping them from growing and multiplying, which treats the infection.
Yes, Nitrofurantoin is an antibiotic. However, until broad-spectrum antibiotics that work within the entire body, this medicine is concentrated in the urine, making it ideal for treating bladder and lower urinary tract infections.
Nitrofurantoin is suitable for adults with urinary tract infections. It's generally safe for most people, but there are some exceptions.
You should not take Nitrofurantoin if you are allergic to the active ingredient, or to any of the other ingredients in this medicine.
You should also avoid Nitrofurantoin if you:
Consult your doctor before taking this medicine if you have any of the following medical conditons:
Tell your doctor or pharmacist if you take any other medicines, natural health products or supplements. The effect of some medicines may change if they are taken with Nitrofurantoin, especially the following:
For a complete list of precautions and medicine interactions, consult the patient information leaflet.
Most people start feeling better within 2–3 days of taking this medicine, however it's important to finish the full course, even if you feel better. This will ensure the infection is properly treated and doesn't return.
You should stop taking Nitrofurantoin and seek immediate medical attention if you experience any of the following side effects:
Yes, you can buy Nitrofurantoin capsules online at SpeedyHealth after completing our free online consultation.
You must complete an online consultation as Nitrofurantoin is a prescription-only medication. This is a quick and easy process which allows our doctors to ensure this medicine is safe and suitable for you to use.
Medically reviewed by Dr. Adrian Rawlinson
Written by our editorial team | Last reviewed January 13, 2026
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