Side Effects of Nitrofurantoin: What to Expect During Treatment

Urinary tract infections (UTIs) are one of the most common bacterial infections in the UK. According to the UK Health Security Agency (UKHSA), there were over 189,000 hospital admissions linked to UTIs in England in 2023–2024, accounting for more than 1.2 million bed-days. With such a high number of people affected each year, effective antibiotic treatment remains essential.

Nitrofurantoin is one of the most commonly prescribed antibiotics for UTIs. It works by eliminating the bacteria responsible for the infection, easing symptoms like pain, burning, or frequent urination. While highly effective, it’s important to understand the potential side effects so you can manage them safely and know when to seek advice from our pharmacists.

In this article, we explore nitrofurantoin side effects, how to take it safely, and what you can expect during your course of treatment.

What Is Nitrofurantoin, and How Does It Work?

Nitrofurantoin is an antibiotic that targets bacteria responsible for urinary tract infections. It works by damaging the bacterial cells, preventing them from multiplying and spreading.

It is available as tablets, capsules, and a liquid suspension for people who struggle to swallow pills. Nitrofurantoin is not suitable for infections outside the urinary system or for kidney infections.

What Are the Common Side Effects of Nitrofurantoin?

Most people taking nitrofurantoin experience no major issues, but some may notice mild side effects. These usually settle once your body gets used to the medicine.

Stomach or Gut Problems

Nausea, vomiting, diarrhoea, or loss of appetite are among the most common nitrofurantoin side effects. Taking the medicine with food or milk can help reduce stomach upset.

Headache and Dizziness

Some people feel a little dizzy or experience headaches while on treatment. Rest, hydration, and mild pain relief (such as paracetamol, if suitable) can help. Avoid driving or operating machinery until these symptoms ease.

Drowsiness and Tiredness

A common question is “Does nitrofurantoin make you sleepy?” For some people, it can cause mild drowsiness or fatigue. If you find that nitrofurantoin makes you tired, plan to take it when you can rest and avoid tasks that need full concentration.

Changes in Urine Colour

Nitrofurantoin can make urine appear dark yellow or light brown. This is completely harmless and disappears after treatment ends.

Skin Reactions

Occasionally, you may notice mild itching or a light rash. If the rash becomes severe or is joined by swelling, stop the medicine and contact our pharmacists promptly.

Can Nitrofurantoin Cause Other Side Effects?

Although uncommon, a few other effects have been reported by some people.

Can Nitrofurantoin Cause Thrush?

Yes, it can in some cases. Because antibiotics affect the balance of bacteria in your body, nitrofurantoin may cause thrush, particularly in women. Signs include itching or discomfort in the genital area. Our pharmacists can recommend suitable antifungal treatments if this occurs.

Nitrofurantoin and Blood Pressure

There is no clear evidence that nitrofurantoin causes high blood pressure. However, if you already have high blood pressure, always mention it during your consultation so our pharmacists can check your suitability.

Nitrofurantoin and Acne

There is no proven link between nitrofurantoin and acne. If you develop new skin breakouts, it may be due to another cause rather than the antibiotic itself.

What Are the Serious Side Effects of Nitrofurantoin?

Serious reactions are very rare but important to recognise early. Stop taking the medicine and speak to our pharmacists or seek urgent help if you notice any of the following symptoms.

Breathing or Chest Problems

A persistent cough, tight chest, shortness of breath, or fever may signal inflammation in the lungs. This needs medical review as soon as possible.

Liver Issues

In rare cases, nitrofurantoin may affect the liver. Signs include yellowing of the skin or eyes (jaundice), dark urine, pale stools, or abdominal pain.

Nerve Problems

Very rarely, nitrofurantoin may affect the nerves (called peripheral neuropathy). Tingling, numbness, or burning sensations in the hands or feet require urgent assessment.

Severe Allergic Reactions

Swelling of the face, lips, or throat, difficulty breathing, or widespread rash and itching could indicate a serious allergic reaction. Stop the medicine immediately and seek emergency help.

Who Should Avoid Taking Nitrofurantoin?

Nitrofurantoin is not suitable for everyone. You should not use it if you:

• Have severe kidney problems that reduce medicine clearance.
• Have had previous lung or liver issues related to nitrofurantoin.
• Are near the end of pregnancy or are giving the medicine to a baby under three months old.
• Have a condition called G6PD deficiency.

Always provide full details of your health and any medicines you take when completing your online consultation. This helps our prescribers decide whether nitrofurantoin is right for you.

How Should I Take Nitrofurantoin Safely?

Follow the dosage instructions given by our pharmacists carefully to make sure the medicine works effectively.

Typical Doses

• For an active UTI: usually twice daily for 3 to 7 days.
• For prevention: a lower daily dose may be recommended long-term.

Take each dose with food or milk and a full glass of water to improve absorption and reduce stomach discomfort.

Missed Dose

If you forget a dose, take it as soon as possible. If it is nearly time for your next dose, skip the missed one. Do not take two doses together.

Alcohol

There are no known harmful interactions between nitrofurantoin and alcohol, but alcohol may increase dizziness or nausea. Avoid drinking until you finish the course.

How Can You Manage Nitrofurantoin Side Effects?

Even though side effects are mostly mild, there are steps you can take to feel better during treatment.

Reduce Stomach Upset

Always take nitrofurantoin with food. Eat smaller, more frequent meals, and avoid very spicy or greasy food if you feel nauseous.

Stay Hydrated

Drink plenty of water throughout the day. This helps flush bacteria from your urinary system and prevents dehydration if diarrhoea occurs.

Manage Headaches or Dizziness

If you get headaches, rest in a quiet space and take simple pain relief if suitable for you. Move slowly when standing up if you feel dizzy.

Deal with Tiredness

If you find nitrofurantoin makes you tired, allow extra rest. Avoid strenuous activity until your energy returns after completing the course.

When Should You Speak with Our Pharmacists?

You should contact our pharmacists if you:

• Experience ongoing side effects that don’t improve.
• Notice yellowing of your skin or eyes, persistent cough, or numbness in your hands or feet.
• Develop a severe rash, swelling, or breathing difficulty.

Our pharmacists are available for confidential support and can advise whether to continue treatment or arrange a different medicine if needed.

Safe and Effective UTI Relief with Pharmacy Planet

Nitrofurantoin is an effective, trusted treatment for urinary tract infections when used correctly. Understanding its potential side effects can help you stay safe and comfortable throughout treatment. Most people complete their course without problems, and simple steps like taking it with food, drinking water, and resting when tired can make a big difference.

Shop UTI medicines online at Pharmacy Planet. Start a quick and secure online consultation with our pharmacists today to find the most suitable treatment for your symptoms. All prescriptions are reviewed by UK-registered prescribers and delivered quickly and discreetly to your door.

Frequently Asked Questions (FAQ's)

Does nitrofurantoin make you sleepy?

Yes — some people find that taking nitrofurantoin can lead to feelings of drowsiness or mild sleepiness. If your alertness is affected, it’s best to avoid driving or using heavy machinery until you know how the medicine affects you.

Can nitrofurantoin make you tired?

It can. Feeling unusually tired or fatigued is a recognised side effect of nitrofurantoin, particularly during treatment of a urinary tract infection when your body is also working hard to fight off the bacteria.

Can nitrofurantoin cause thrush?

Yes — because nitrofurantoin (like many antibiotics) may disturb the normal bacterial balance in your body, you may be more susceptible to a fungal infection such as thrush. If you experience genital itching or discomfort, speak to our pharmacists.

Does nitrofurantoin affect blood pressure or cause high blood pressure?

There is no strong evidence that nitrofurantoin causes high blood pressure. However, if you already have hypertension, it is wise to mention this when completing your consultation so our pharmacists can check your suitability.

Could nitrofurantoin acne be a side effect of use?

While worsening or new acne is not a commonly reported side effect of nitrofurantoin, any new skin changes during a course should be reviewed. If you notice persistent breakouts, consult our pharmacists for assessment.

What are the main nitrofurantoin side effects I should watch for?

The main side effects of nitrofurantoin include gastrointestinal upset (nausea, diarrhoea), changes in urine colour, dizziness or fatigue, and mild skin reactions. Rare but serious effects include lung or liver issues and nerve damage — if you experience shortness of breath, yellowing of your skin or eyes, or tingling in hands/feet, you should seek advice immediately.