What is Trimethoprim?
Trimethoprim is an antibiotic treatment used to treat bacterial infections, bladder (cystitis) and urinary tract infections (UTIs). It is included on the World Health Organisation's List of Essential Medicines. As a prescription medication, it isn’t available over the counter.

Trimethoprim is an effective antibiotic for treating cystitis. In some regions of the UK, there is increasing resistance to this antibiotic and as a result, you may have been treated before with another medication called nitrofurantoin. You may have found that nitrofurantoin is unsuitable for you and caused side effects, in which case trimethoprim is a suitable choice to treat your UTI.

How do I get a bladder or urinary tract infection?
UTIs can be painful and upsetting, but they are easy to treat. Some women are more prone to them than others, and there are some lifestyle changes that you may want to look into if it’s a recurring problem. It’s important to take care of your vaginal and sexual health as there may be repercussions when it comes to intimacy, relationships and fertility. You can read more about the prevention of cystitis on our advice page.

Most cases of cystitis or UTIs are caused by E.coli, which originates in your gut. Trimethoprim does not kill E.coli. Instead, it stops bacterial DNA synthesis, meaning that the bacteria cannot replicate. This allows your immune system to destroy the infecting bacteria until they are eradicated and your infection is resolved.

How do I take Trimethoprim 200mg tablets?
The NHS advises that for most uncomplicated cases of cystitis, Trimethoprim 200mg tablets should be taken twice daily, one dosage every 12 hours until the prescribed course is complete. This is normally a three-day course for uncomplicated cystitis. However, it can also be prescribed as a seven-day course. NHS guidance states that your doctor may recommend your first dosage is doubled to 400mg - this is normally only if your symptoms are severe. You should start taking Trimethoprim as soon as you feel the onset of cystitis symptoms.

There are other antibiotics your doctor may feel are more suited to you. These include nitrofurantoin, quinolones, or amoxicillin. Speak to your prescriber to find out more about treating UTIs with antibiotics.

Interaction with food, alcohol, and other UTI medications
Trimethoprim is not affected by food or alcohol, with neither causing resistance or reaction if you consume them while taking your prescription. This means there is no need to alter your diet whilst taking Trimethoprim.

Trimethoprim can be safely taken with other over-the-counter cystitis treatments available, such as Cymalon and Cystopurin, which help to reduce the acidity of the urine. You can also take simple painkillers, such as Paracetamol and Ibuprofen, alongside Trimethoprim with no problems.

Taking Trimethoprim will also not stop your birth control medication (contraceptive pill) from working.

Trimethoprim dosage and resistance
Your symptoms will normally improve within 24 - 48 hours of taking Trimethoprim 200mg medication. You should always complete the course, even if you feel better. If your prescribed Trimethoprim 200mg capsules have not improved your symptoms, and you are still feeling the effects of your urinary tract infection after the three-day course, you should see your doctor. This may suggest that your UTI is resistant to Trimethoprim and requires a different UTI antibiotic, such as the first-line UTI antibiotic called Macrobid. It could also indicate that your symptoms are caused by something other than a bacterial infection, which requires investigation.

Trimethoprim can also be used to prevent cystitis at a dose of 100mg at night. You would need to see your doctor to discuss recurrent bouts of cystitis to see if Trimethoprim 100mg tablets are suitable for you.

Non-prescription alternatives to Trimethoprim
Cymalon sachets are some of the most popular cystitis remedies in the UK. Cymalon sachets contain sodium citrate, which helps to neutralise urine acidity during an attack of cystitis, providing welcome relief from the burning pain and irritation. Keep them in the bathroom for easy access when the first symptoms show.

It is important to drink plenty of fluids when you are suffering from cystitis to help flush the bacteria through your system. It is also important to keep hydrated to prevent cystitis from recurring.

Sources
Trimethoprim 200mg Tablets Patient Information Leaflet: https://mhraproducts4853.blob....
https://bnf.nice.org.uk/drug/trimethoprim.html
https://www.nhs.uk/medicines/trimethoprim/
https://www.nice.org.uk/guidance/ng109/chapter/Recommendations
Trimethoprim dose for UTI
Take one Trimethoprim 200mg tablet twice daily, roughly 12 hours apart
You should always continue the course until it is complete, unless otherwise directed by a doctor
You should start taking Trimethoprim 200mg tablets as soon as you recognise the symptoms from cystitis that has previously been diagnosed by your GP
You should see your GP if no improvement in your symptoms once the course is complete
If you notice blood in your urine, or suffer from a fever, chills, back pain, or vomiting your infection may be more serious and you should see your GP as soon as possible.

If you find that you have suffered with cystitis more than three times in one year you should see your GP for an investigation into the cause of your recurrent infections.

Trimethoprim ingredients
Your treatment contains 200mg of Trimethoprim per tablet.

Trimethoprim side effects
It is possible that you may be allergic to Trimethoprim. If you know you are allergic to Trimethoprim or have suffered a reaction previously do not take Trimethoprim and discuss alternatives with your GP.

Trimethoprim has a small risk of nausea, vomiting, diarrhoea, and skin rash (as with many medicines). Please read the Patient Information Leaflet enclosed with your medicines for a full list of side effects.

If you experience any adverse effects from taking Trimethoprim 200mg tablets it is important to let us know immediately. Please log in to your online account and message one of our healthcare professionals or alternatively call us on 03322 00519. In a medical emergency you should contact the emergency services or go straight to your local accident & emergency department.

You should read the patient information leaflet in full before taking Trimethoprim.

Trimethoprim warnings
Please ensure that you read the Patient Information Leaflet enclosed with your treatment.

You should not use trimethoprim in the following circumstances:

You are allergic to trimethoprim
You have kidney or liver disease (or problems with either organ)
You have a blood disorder, such as folate deficiency*
You have hyperkalaemia
You have galactose intolerance, total lactase deficiency or glucose-galactose malabsorption
*If taking trimethoprim leads you to develop anaemia, your GP may advise you to take folic acid to tackle the anaemia (though this is very unlikely with a short course).

Trimethoprim and other medicines
Trimethoprim 200mg tablets should not cause a harmful interaction with any of your other current medicines. However, it should not be taken if you currently take any of the following medications:

ACE inhibitors (such as ramipril)
Azathioprine
Cyclosporin
Dapsone
Digoxin
Eplerenone
Heparin
Mercaptopurine
Methotrexate
Phenytoin
Procainamide
Pyrimethamine
Repaglinide
Rifampicin
Warfarin
Trimethoprim in pregnancy and breastfeeding
Trimethoprim should not be used during pregnancy and should only be used under the specific advice of your doctor during breastfeeding.