Get the 121doc appReorder in just 3 clicks. It’s free
View

Trimethoprim

Cystitis|Active ingredient(s): Trimethoprim|Manufacturer: Various

A young smiling woman taking a tablet with a glass of water

Fast and effective cystitis relief with Trimethoprim

  • Targets harmful bacteria directly
  • Improves symptoms like burning within days
  • Strong antibiotic for effective treatment
  • Twice-daily dosing for cystitis
  • 200 mg tablets

How to use

Close up of a pair of hands holding a glass of water and a white tablet

Take as prescribed

Follow the exact course your doctor recommends. Swallow each tablet whole with a glass of water.

A small red flag stuck into a calendar on a specific date

Be consistent

Don’t miss a dose. Keeping a steady level of Trimethoprim in your body helps it work effectively.

A smiling woman outside

Complete the course

Finish all tablets prescribed, even if symptoms improve before then. Stopping too soon can allow the infection to return.

What others say about Trimethoprim

Trustpilot review
18 reviews with score 4.8

Quality healthcare
made easy

Price is all-inclusive.
Consultation is included.
Prescription is included.

Free shipping.
UK: Free next-day delivery.
Discreet packaging.

Licensed doctors.
Registered pharmacies.
Certified online pharmacy.

Trimethoprim

What is Trimethoprim?

Trimethoprim is an antibiotic that can be used to treat many bacterial infections. It is particularly effective at treating urinary tract infections like cystitis, and usually clears symptoms within 3 days. 121doc offers 200 mg Trimethoprim tablets for the treatment of cystitis.

How does Trimethoprim work?

Trimethoprim targets the infection-causing bacteria directly to clear up symptoms. Trimethoprim works by inhibiting folic acid; an enzyme that the bacteria need to multiply. Without folic acid, the bacteria cannot survive and your immune system is then able to effectively fight off the infection. When taken for the full prescribed course, Trimethoprim should clear up all symptoms of cystitis and your infection entirely.

What is Trimethoprim used for?

Trimethoprim is mainly used to treat urinary tract infections (UTIs) like cystitis. It can also be used for other conditions, including certain chest and ear infections, but less commonly. Though highly effective, it is usually only prescribed when Nitrofurantoin cannot be, due to its higher risk of bacterial resistance.

Click here to see if Nitrofurantoin is a better option for you.

How long does Trimethoprim take to work?

Trimethoprim is highly effective when used correctly, with most people noticing relief from symptoms within two to three days of starting treatment. In most uncomplicated UTIs, a full 3-day course is enough to successfully clear the infection, making it the fastest way to get rid of cystitis.

It also has a high success rate. Clinical research has found Trimethoprim to be over 90% effective as a treatment for uncomplicated cystitis.

Who can use Trimethoprim?

Men and women over the age of 18 can be prescribed Trimethoprim from 121doc, and only when Nitrofurantoin is ineffective.

Do not take Trimethoprim if you:

  • are allergic to any ingredient found in this medicine
  • are pregnant or breastfeeding
  • have a blood disorder, such as anaemia
  • have liver problems

How do I take Trimethoprim?

For cystitis, the recommended dose is one 200 mg tablet twice a day for 3 days, unless suggested otherwise by your doctor. To prevent cystitis from recurring, take 100 mg once daily before bed.

Here are some tips to ensure you take your tablets correctly:

  • Take your tablets whole with a glass of water.
  • Space your doses evenly (e.g. morning and evening).
  • If it makes you nauseous, take your tablets with food or milk.

Also make sure to complete the full course prescribed, or you risk your infection coming back, even if symptoms improve before then.

When should I take Trimethoprim?

You can take Trimethoprim at any time that suits you, but it is most effective when taken once in the morning and once in the evening. This spaces out your doses, ensuring a steady stream of the medicine in your system.

Why take Trimethoprim at night?

Taking Trimethoprim at night before you sleep is especially important, as your body naturally urinates less during sleep. This allows the medicine to remain in your urinary system longer and work more efficiently. It can also make it easier to remember to take your dose at the same time each day, which is important for maintaining consistent levels of the medicine in your body.

Does Trimethoprim have any side effects?

Yes, Trimethoprim can cause some side effects, but they are usually short-lived and rarely serious.

The most common Trimethoprim side effects include:

  • high levels of potassium in the blood (hyperkalaemia)
  • nausea or vomiting
  • diarrhoea
  • headache
  • skin rashes
  • thrush
  • hives

This is not an exhaustive list. For a full list of side effects, consult the patient information leaflet.

Is Trimethoprim a strong antibiotic?

Yes, Trimethoprim is a strong antibiotic. While this makes it highly effective, it also means you shouldn’t take it too often, as frequent use can increase the risk of antibiotic resistance and reduce its effectiveness when you really need it. It’s important to tell your doctor how often you use it and only take the prescribed amount.

Can you drink alcohol with Trimethoprim?

Yes, you can drink alcohol while taking Trimethoprim, but you should only do so in moderation to avoid side effects. Alcohol does not stop Trimethoprim from working or make it less effective, but it may make you feel worse.

Can I get Trimethoprim without a prescription?

No, you cannot get Trimethoprim tablets without a prescription. Safety is our number one priority at 121doc. For this reason, our doctors will only prescribe treatment if you meet the criteria in your online consultation.

A prescription from a trusted healthcare provider like 121doc ensures:

  • safety during treatment
  • effective results
  • monitoring of side effects
Medical review byDr. Caroline FontanaLast review 19 November 2025
Dr. Caroline Fontana

Note: You must complete a short online consultation so that our doctor can ensure that the treatment is suitable for you. The above pricing should only be used as a reference. The final decision to issue this treatment lies with the prescribing doctor.

Trimethoprim Overview

Type of medicine Antibiotic
Used for Cystitis
Active ingredient Trimethoprim
Works by Killing the bacteria causing the infection and preventing it from spreading
Effective within A few days
Available as Tablets
Available dosage(s) 200 mg
Usage instructions For cystitis: take a 200 mg tablet twice daily for 3 days
Packaging Blister pack containing 6 tablets
Manufacturer Various

FAQs

What is included in the online consultation?
Will a doctor review my consultation?
What happens after I submit my order?
What services are included with my order?
Is the price all-inclusive?
What are my delivery options?
Is it safe to buy prescription medication online?
Is this service discreet?
What is included in the online consultation?

Our online consultations are in the format of short medical questionnaires. You will be asked general questions about your health and medical history, as well as specific medical questions relevant to the treatment you have chosen. We will also ask you for your payment and delivery details to complete the order.

Online consultations take no longer than 5 minutes to complete. All questions are necessary when issuing prescription medicines. It means that our doctors can make sure the treatment is safe and right for you.

Will a doctor review my consultation?

Yes, it is a legal requirement that all online consultations are reviewed by a registered doctor. This is to make sure the chosen treatment is safe and right for you to take. All personal information is stored securely and confidentially.

Please note, all orders are subject to doctor approval, and we cannot guarantee that your order will be approved.

What happens after I submit my order?

Your online consultation will be sent directly to our medical team, where it will be reviewed by on of our in-house doctors.

If a doctor approves you for treatment, they will issue a prescription. Your prescription will then be forwarded to our pharmacist, where you medication will be dispensed and dispatched for delivery.

What services are included with my order?

Every order includes:

  • Free consultation - your consultation will be personally reviewed by one of our registered doctors.
  • Free prescription - a doctor will issue you a prescription if approved for treatment.
  • Free delivery - we provide free express delivery across Europe, you should receive your order in 1-2 working days.
Is the price all-inclusive?

Yes, our service is all-inclusive and there are no hidden fees. All 121doc orders include a free online consultation, a free prescription and free express delivery.

What are my delivery options?

We offer several delivery options at no extra charge:

  • Next-day delivery
  • UPS Access Point - convenient parcel drop-off and collection near your home or work address
  • Nominated-day delivery - choose the most convenient day for delivery

All these options can be tracked and require a signature on delivery. If you are not in, a friend or relative can sign in your place.

Is it safe to buy prescription medication online?

It is safe to buy prescription medications online from genuine and reputable healthcare providers, like 121doc.

Our medical staff and facilities are registered with the relevant medical governing bodies. We also ensure your data is protected by adhering to European data privacy laws.

You can learn more about our certifications here.

Is this service discreet?

Our patients’ privacy is of utmost importance. All your medical information is securely stored and only viewed by our doctors. We do not share your details with third-parties. We are also closely adhere to data privacy laws.

All orders will only show on invoices, bank statements, etc. as ‘HHC Ltd’.

Other treatments that might interest you

Contraceptive pills, ring and patch

We offer many contraceptive treatments and advice on the best fit for you.

  • All popular contraceptives
  • Home delivery
  • Delivered to your door tomorrow

Various treatments available

Get your Hormone Replacement Therapy easily online.

  • Many treatments available
  • Home delivery
  • Delivered to your door tomorrow

How does it work?

Select
Select Select your treatment and complete our online consultation.
Free consultation

Conditions:

Select a condition here or use the top menu. For every condition, we provide you with information as well as the treatments we currently offer. If you don’t know which is best for you, just click the 'Advise-me' button.

Treatments:

If you know what you want, the quickest way to find a specific medication is to use the search bar here.

Ordering:

Every order starts with an online consultation. We will ask you medical questions to make sure only treatment that is safe and effective is prescribed. We take into account your lifestyle, health and any other medications you’re currently using.

The consultation is completely free, and takes between 5 and 10 minutes of your time.

All your information is safe with us. We don’t share it with anyone unless you want us to.

Help:

If you need any guidance, you can call, message or email our customer service team via the ‘How can we help you?' section here.

Prescribe
Prescribe Our doctors review your order.
Free prescription

Review:

As soon as you place the order, one of our doctors will review your consultation. On working days, this usually takes around one hour.

Questions:

If the doctor has any additional questions, you will receive a phone call and an email. We understand you might be at work or busy. Our customer service representatives are always discreet and can call back at a more convenient time if necessary.

Our emails never contain any personal or medical information, only a link to your private account on our website (where you will find your messages).

Pharmacy:

Once our pharmacy receives your prescription, you will get a second email with your package tracking code.

Deliver
Deliver Expect your delivery the next working day.
Always free. Discreet packaging.
Free next-day delivery

Free:

All orders include next-day delivery. Alternatively, you can select a delivery date that suits you better.

Location:

We also provide a free UPS Access Point service. Pick up your package from one of many collection points across the UK.

With your tracking code, you will know the estimated delivery time. All we need is your signature (or a friend‘s or relative’s).

Discreet:

All parcels are plainly labelled; there is no logo or any indication of its contents. Inside, you will find your treatment as well as a patient leaflet in your chosen language.

Repeat
Repeat Subscribe and save with our repeat service. Never miss a dose again.
10 to 15% off

Repeat:

With 121doc’s Subscribe & Save service, you can automatically receive your treatment every few weeks or months.

The order will be generated by us, using the information you provided (including delivery frequency). You don’t have to do anything. Payment is taken two days before shipping.

Subscribe:

There are two ways to subscribe. The first is during the order process. The second is via your profile here.

You can cancel or amend your repeat prescriptions at any time.

Save:

There are no sign-up fees with this service. Plus, you get a 10% discount off all future prescriptions, increasing to 15% after six orders!