Treatment options

With NowPatient's private treatment plans you can treat Cystitis with trimethoprim safely and easily in a few simple steps. Get started by selecting the medication you are interested in or by hitting the start consultation button below.

Includes Free Private Prescription
This content is intended for UK audiences only

We connect you to a prescribing clinician by secure video link who will spend time with you to understand your requirements and ensure that trimethoprim is appropriate, safe and effective for you. The consultation is FREE and you only ever pay for the medication, if it is prescribed. Medications are supplied and delivered discreetly by NowPatient.

112 people rated this product 5 stars
Please select form
Please select pack size


Only £ per Pack

Safe and regulated service
CQC Logo
Dispensed in the UK
Registered Pharmacy Logo
Delivered securely by Royal Mail
Royal Mail Logo
Table of contents
OverviewOther known brand namesAbout trimethoprimKey facts of trimethoprimWho is trimethoprim not suitable for?How and where to get trimethoprim?Dosage and strength for trimethoprim for cystitisInformation about how to take trimethoprim tablets for cystitisWhat happens if you take too much trimethoprim?What are the side effects of trimethoprim?Information about taking trimethoprim at the same time as other medications or herbal supplementsWhy might trimethoprim not work for cystitis?Can trimethoprim taken for cystitis be taken long term?Is there a herbal trimethoprim?Can women use trimethoprim?Should I avoid any particular food or drink when taking trimethoprim?What lifestyle changes can I make to help me with cystitis?Alternatives to trimethoprimSourcesPeople also asked
Navin Khosla NowPatientGreen tick
Medically reviewed by Navin Khosla, BPharm and written by Rajive Patel, BPharm - Updated on 26 Jan 2024
Share this post
What to do if you missed your trimethoprim dose

The MHRA's reporting program for suspected side effects to medicines, vaccines, e-cigarettes, medical device incidents, defective or falsified (fake) products to the Medicines and Healthcare products Regulatory Agency to ensure safe and effective use.

Learn more about reporting side effects

Other known brand names


About trimethoprim

Trimethoprim is an antibacterial agent used for the treatment of bacterial infections, cystitis and urinary tract infections (UTIs). Trimethoprim stops bacterial dihydrofolate reductase, an enzyme that helps with the formation of tetrahydrofolic acid, preventing the production of bacterial DNA. Trimethoprim may be used alone or with sulfamethoxazole (co-trimoxazole) for the treatment and/or prophylaxis of UTIs.

Now Patient offers trimethoprim as a treatment for cystitis only, following an online consultation with a prescribing clinician.

Key facts of trimethoprim

  • Trimethoprim is an antimicrobial used to treat bacterial infections, cystitis and UTIs
  • Trimethoprim can be taken up to 3 days
  • Trimethoprim has some common side effects which include nausea and vomiting
  • It can be dangerous if you take trimethoprim with certain medications. If you’re not sure if it is safe, discuss this with the prescribing clinician

Who is trimethoprim not suitable for?

Trimethoprim may not be suitable for some people. To make sure it’s safe for you, speak to the prescribing clinician before taking trimethoprim if you:

  • Are allergic to trimethoprim
  • Have liver or kidney disease
  • Have high blood potassium levels (hyperkalemia)
  • Have galactose intolerance, glucose-galactose malabsorption, or total lactase deficiency
  • Have anemia or folate deficiency (low folic acid in your blood)
  • Have porphyria or any other blood disorder
  • Are pregnant or trying to get pregnant

How and where to get trimethoprim?

Trimethoprim is only available with a prescription. It is not available over the counter at a pharmacy.

Now Patient does not allow customers to buy trimethoprim directly. Our service is certified, safe and effective, and we only ever treat conditions. If you book a consultation with a prescribing clinician for the treatment of cystitis, you can discuss if trimethoprim is a suitable treatment option for you.

At the end of the consultation, the clinician will decide if a treatment plan is suitable for you. If it is, the clinician will issue you with a prescription which can then be ordered, paid for and delivered directly to your chosen address by Now Patient.

Dosage and strength for trimethoprim for cystitis

Trimethoprim is available in tablet form when used for cystitis. It is available in strengths ranging from 100 mg to 200 mg.

Information about how to take trimethoprim tablets for cystitis

Trimethoprim 200mg tablets should be taken twice daily (every 12 hours) until the prescribed course is complete. It is normally a 3-day course for uncomplicated cystitis, but can be prescribed as a 7-day course.

If you have blood in your urine, have back pain, fever, chills, vomiting, or have had cystitis more than three times in one year you should see your GP as soon as possible.

What happens if you take too much trimethoprim?

If you take more than prescribed, then it can lead to some unpleasant side effects. You should talk to your doctor or reach out to one of our prescribing clinicians, if you have taken too much trimethoprim and you experience any of the following side effects:

What are the side effects of trimethoprim?

Side effects of trimethoprim are split into common and serious.

Common side effects include:

  • Nausea, vomiting, diarrhoea, and skin rash

If you experience any serious adverse effects, you should contact NHS 111.

If you experience a serious allergic reaction with the signs shown below you should contact emergency services on 999.

  • Your lips, mouth, throat or tongue suddenly become swollen
  • You’re breathing very fast or struggling to breathe (you may become very wheezy or feel like you’re choking or gasping for air)
  • Your throat feels tight or you’re struggling to swallow
  • Your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
  • You suddenly become very confused, drowsy or dizzy
  • Someone faints and cannot be woken up

Always report adverse effects to the MHRA yellow card reporting system. You can read more about this here How and where do I report side effects of my medication? – NowPatient

Information about taking trimethoprim at the same time as other medications or herbal supplements

There is not enough evidence to suggest there are any drug interactions between herbal supplements and trimethoprim. In any event, you should let your prescribing clinician know if you are taking any herbal supplements or other prescription drugs, such as:

  • ACE inhibitors
  • Azathioprine
  • Cyclosporin
  • Digoxin
  • Methotrexate
  • Phenytoin
  • Repaglinide
  • Rifampicin
  • Warfarin, heparin

Why might trimethoprim not work for cystitis?

Trimethoprim may not work for you. A common reason may include aquired trimethoprim resistance.

Can trimethoprim taken for cystitis be taken long term?

Taking a 3-day course of trimethoprim should clear most bladder and urinary tract infections. If your symptoms have not cleared once you have completed your course of trimethoprim, speak to your doctor for medical advice.

Is there a herbal trimethoprim?

No. Herbal trimethoprim does not exist. If you have been marketed such a formulation, it may be fake.

Can women use trimethoprim?

Women can take trimethoprim for the treatment of cystitis. However, trimethoprim should not be used during pregnancy and only under the guidance of your doctor when breastfeeding.

Should I avoid any particular food or drink when taking trimethoprim?

You can eat and drink normally when taking trimethoprim.

What lifestyle changes can I make to help me with cystitis?

You may modify your lifestyle in a number of ways, and this may have a positive impact on your cystitis. Drink plenty of water when suffering from cystitis to flush bacteria through your system and to help keep hydrated to prevent cystitis from recurring. Also, wipe from front to back when you go to the toilet, to prevent infection.

Alternatives to trimethoprim

Alternatives for the treatment of cystitis include nitrofurantoin, quinolones, or amoxicillin.


Medical Disclaimer

NowPatient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information in this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.

The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.

People also asked Icon

People also asked

What is NowPatient

Telehealth and Online Pharmacy

NowPatient is a licensed online pharmacy and doctor service that is available around the world. Our service is FREE and packed with valuable features that can benefit your health such as medication reminders, educational blogs, medically approved symptoms checker, UK NHS online pharmacyprivate treatment plansRx Advantage cardhealth conditions information, affordable medications options, genetic testinghome test kitshealth riskspollen meterair quality monitor, and lots more!

See how we are different
A pink bottle of pills and a bottle of medicine.


To improve the lives of everyone by making high-quality care accessible and convenient

We are here to improve lives. Our service gives you access to smart features and resources that can help empower you to take control of your health and improve your health outcomes. All this, in one place, for FREE. We strive to bring a fresh perspective to managing health. NowPatient can be accessed by downloading the App or using your web browser.

Download our app today

A mobile phone with a health app and a pollen meter.

Can I trust NowPatient

Meet our medical review team

Trustworthy and reliable medical content authored and reviewed by our experienced team of medical professionals from the United Kingdom and the United States. Learn more about our team and our editorial process by clicking on the buttons below.


Medical Review Team Avatars

Your Questions Answered

For your peace of mind, we can answer your questions quickly

We have a comprehensive list of FAQ’s on each feature page. Alternatively, for broader questions around our service just click the button below.
Find your answers