Please note that since 2017, Nitrofurantoin has been the most widely prescribed first line treatment for cystitis, although some women may find either Nitrofurantoin or Trimethoprim responds better to their symptoms.
Please note, women who have taken Trimethoprim in the past year should consider Nitrofurantoin instead.
Please note, the branded Macrobid (Nitrofurantoin) capsules that Medical Specialists® supply, are manufactured in packs of 14. Therefore, you may receive a plain box with a printed patient information leaflet (PIL) if a larger pack has to split. Rest assure, Medical Specialists® only ever supply fully UK licensed medicines.
What is Nitrofurantoin for?
Nitrofurantoin is an antibiotic used to treat urinary tract infections (UTIs), such as uncomplicated cystitis. Patients must carry on taking this medicine until the course is completed, even if you feel better after the first day for example. Due to more of the bacteria that causes cystitis becoming increasingly resistant to the antibiotic Trimethoprim, Nitrofurantoin is more commonly prescribed and is considered a more effective treatment. Although Nitrofurantoin is usually the first choice for cystitis, Trimethoprim is still very effective for some women.
How does Nitrofurantoin work?
When you take Nitrofurantoin, your body quickly filters it out of your blood and into your urine. This is beneficial if you have a urinary tract infection such as cystitis as the drug will be concentrated at the site of infection. Therefore, Nitrofurantoin is not suitable for other types of infections. Nitrofurantoin may turn your urine a yellow or brown colour during your course of treatment. This is normal and a more normal colour will be visible once you have completed the treatment.
How to take Nitrofurantoin
• Adults: 100mg slow-release capsules twice daily for 3 days to treat uncomplicated cystitis.
• Improvements should be seen in 24 hours and symptoms are usually cleared after the 3 days.
• If your symptoms do not improve or are worsening after your course of treatment, consult your Doctor.
Choosing Nitrofurantoin or Trimethoprim for Cystitis
Nitrofurantoin is now the most widely prescribed first line treatment for cystitis, although some women may find either Nitrofurantoin or Trimethoprim responds better to their symptoms.
Both are effective antibiotic treatments for cystitis, although there is believed to be increasing antibiotic resistance to Trimethoprim. Up to approximately 30% of bacteria responsible for water infections are resistant to Trimethoprim.
However, some women may find one of the other treatment is more suitable for them and their infection responds better to a particular antibiotic, or they may find they experience less side effects with either Nitrofurantoin or Trimethoprim.
If you are not sure which antibiotic treatment is more suitable for you, your Doctor should be able to offer appropriate guidance.
Where can I buy Macrobid / Nitrofurantoin online?
You can buy Macrobid / Nitrofurantoin with or without a prescription at Medical Specialists, after completing a simple online consultation. Just complete an online consultation by clicking the orange button above. We are the UK’s leading online supplier of prescription medication in the UK and our pharmacy which is regulated by the Royal Pharmaceutical Society of Great Britain.
Ask Our Prescriber / Pharmacist
Medical Specialists® are proud of our in-house team of Prescribers, Pharmacists and Experts who carry out the online consultations, dispense medication or help our patients in other ways.
If you would like to ask one of our experts any questions regarding your medication or any other matter, then please feel free to submit your query to us and will get back to you.

How We Package Your Order
Your medication is sealed in a plain shipping box for protection then placed inside a tamper-proof Royal Mail special delivery envelope before being dispatched from our in-house NHS pharmacy.
- Discreet Plain Packaging
- Royal Mail Special Delivery
- No Mention of Medication
For full patient information, please read or print out the leaflet provided at the bottom of this page.
This patient information leaflet is provided for information purposes only. This leaflet information should not be used in contradiction with your Doctor or Pharmacist's advice. Medical Specialists recommend that you carefully read the information leaflet provided with your medication. Medical Specialists will not accept liability for information displayed. Please refer to the leaflet provided with your medication for the latest manufacturer's information.
Possible Side Effects
Like all medicines, MacroBID can cause Side Effects, although not everybody gets them. Most of them are mild and disappear
when you stop taking MacroBID. If you experience any of the Side Effects detailed below or any other Side Effects, stop taking
MacroBID and consult your doctor.
All medicines can cause allergic reactions although serious allergic reactions are rare. If you notice any sudden wheeziness,
difficulty in breathing, swelling of the eyelids, face or lips, rash or itching (especially affecting your whole body) STOP TAKING
your medicine and go to a doctor immediately.
Please note that while taking MacroBID your urine may become coloured dark yellow or brown. This is quite normal and not a
reason to stop taking the medicine.
If you notice any of the following Side Effects consult you doctor immediately:
- Your lungs may react to MacroBID. This may develop quickly, within a week of starting treatment or very slowly, especially
in elderly patients. This may produce fever, chills, cough and shortness of breath
- MacroBID may cause the liver to become inflamed, producing jaundice (yellowing of the skin or whites of the eyes).
Other Side Effects are:
- Feeling sick (nausea) and headache
- Loose stools
- Loss of appetite, stomach ache, and being sick (vomiting)
- Dizziness, drowsiness
- Blood cells have been affected in some patients. This may result in bruising, delayed clotting of the blood, sore throat,
fever, anaemia, and a susceptibility to colds or persistent cold
- The nerves outside the spinal cord may be affected causing changes to the sense of feeling and the use of muscles. In
addition headache, extreme changes of mood or mental state, confusion, weakness, blurred vision may occur. These
effects may be severe and in some instances permanent
- A variety of skin rashes or reactions have occurred in some patients. These may appear as flaking skin, a red rash or fever
accompanied by rapid heart rate and severe rash with blistering. Other reactions may include inflammation of salivary
glands (causing facial pains), inflammation of the pancreas gland (causing severe abdominal pain) and joint pains.
- Short-term hair loss
- Raised pressure in the skull (causing severe headaches)
- Urinary infection by germs which are not sensitive to MacroBID.
If any of the Side Effects get serious, or if you notice any Side Effects not listed in this leaflet, please tell your doctor or pharmacist.
DO NOT TAKE MacroBID and talk to your doctor if:
- you are allergic (causing itching, reddening of the skin or difficulty in breathing) to Nitrofurantoin or any of the ingredients
of MacroBID (see Section 6 below) or other medicines containing nitrofurantoin
- you have a disease of the kidneys which is severely affecting the way they work (ask your doctor if you are not sure)
- you are in the final stages of pregnancy (labour or delivery) as there is a risk that it might affect the baby
- you have porphyria (blood disorder)
- in patients with G6PD (glucose-6-phosphate dehydrogenase) deficiency
- in infants under three months of age
- you are breast feeding a baby with suspected or known deficiency in an enzyme called G6PD (glucose-6-phosphate
dehydrogenase).
Tell your doctor if you are not sure about any of the above.
TAKE SPECIAL CARE with MacroBID and speak to your doctor or pharmacist before taking the capsules if:
- you have diabetes
- you are suffering from any illness causing severe weakness
- you have anaemia (a decrease in red blood cells causing pale skin, weakness and breathlessness); a lack of vitamin B or
abnormal levels of salts in your blood (your doctor will be able to advise you).
The above conditions may increase the chance of developing a side effect which causes damage to the nerves, altered sense
of feeling, like pins and needles.
- you lack an enzyme (body chemical) called glucose-6-phosphate dehydrogenase, which causes your red blood cells to be
more easily damaged (this is more common in black people and people of Mediterranean, Middle Eastern or Asian origin.
Your doctor will know)
- you have any disease of the lungs, liver or nervous system. If you need to take MacroBID for a number of months, your
doctor may want to regularly check how your lungs and liver are working
- you have false positive results on testing your urine for glucose
- you have urine coloured yellow or brown.
Taking other medicines:
Please tell your doctor or pharmacist if you are taking or have recently taken any other medicines, including medicines obtained
without a prescription. If they are taken with MacroBID their effect or the effect of MacroBID may be changed.
- Antacids for indigestion (e.g. magnesium trisilicate)
- Medicines for gout (e.g. probenecid or sulfinpyrazone)
- Medicines for raised pressure in the eye (glaucoma), such as carbonic anhydrase inhibitors (e.g. acetazolamide)
- Medicines which make the urine less acidic (e.g. potassium citrate mixture)
- Medicines for infections, known as quinolones
- Oral contraceptive “the pill”. You will need to use extra contraceptive precautions such as using a condom, as antibiotics
can make the contraceptive pill less effective
- Typhoid vaccine, which is given for the prevention of typhoid.
If you are in doubt about any of these medicines ask your doctor or pharmacist.
Taking MacroBID with food and drink:
- MacroBID capsules should be taken at meal times with food or milk. This will help to avoid stomach upset and also to help the
absorption.
Pregnancy and breast-feeding:
- Ask your doctor or pharmacist for advice before taking any medicine. As far as it is known MacroBID may be used in pregnancy.
However it should not be used during labour or delivery because there is a possibility that use at this stage may affect the baby.
If you want to breast feed, please consult with your doctor first.
Driving and using machines:
- MacroBID may cause dizziness and drowsiness. You should not drive or operate machinery if you are affected this way until
such symptoms go away.
Important information about some of the ingredients in MacroBID:
- This medicine contains lactose and sucrose (sugars). If you have been told by your doctor that you are intolerant to some sugars
and have to avoid them, contact your doctor before taking this medicine.