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

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  • Review by a qualified doctor
  • Including prescription
  • Next-day delivery included

How does Trimethoprim work?

When bacterial infections like cystitis spread, the individual cells need to produce DNA. To do this, these cells require a steady supply of folic acid. The cells produce the folic acid themselves, which is then used for the creation of new bacterial DNA. By doing this, the cystitis infection is able to spread faster than the body’s immune system is able to deal with it.

Trimethoprim is an antibiotic that works to prevent the infection from spreading. It does this by stopping the bacterial cells that cause cystitis from synthesising the folic acid that they need to be able to multiply. By acting in this way, this medication stops the spread of infection and renders the remaining cells extremely vulnerable to the immune system. This gives the body time to kill the remaining bacterial cells.

What are the benefits?

Trimethoprim is an extremely effective treatment for cystitis. This condition can cause a great deal of discomfort, with symptoms including pain when urinating and an uncomfortable burning sensation. As the bacteria can multiply so quickly, it can take a while for the body to naturally deal with the infection. This medication will help prevent the bacterial cells from multiplying and thus stop the infection from spreading. This means that Trimethoprim will significantly shorten the life span of the infection and provide quick and fast relief from the symptoms of cystitis.

Trimethoprim can also be used as a long-term preventative treatment for women who suffer from cystitis on a regular basis. For people who experience this as a recurring condition, this medication can be used to reduce the possibility of an infection developing and shorten the time taken for any potential infection to clear. This means that Trimethoprim is an effective treatment for cystitis in both the short and long term.

Who can buy Trimethoprim online?

You can buy Trimethoprim online at 121doc if you are a woman over the age of 18 who is experiencing the symptoms of cystitis. This medication is widely used and well researched and so it is generally well tolerated with a minimal risk of side effects occurring. There are some groups who may not be suitable for this treatment. You may not be suitable for Trimethoprim if you are pregnant or if you have kidney or blood disorders. If this applies to you, please consult with your doctor in order to find the right treatment option for you.

When you order this treatment, you will be required to complete an online medical consultation. It is important that you answer these questions fully and that you include any medical conditions that you are currently suffering from. This will allow our dedicated medical team to determine whether Trimethoprim is a suitable treatment for you. There are some medications that can have an effect on this treatment, so please include any medications that you are currently taking on the online consultation.

How do you use this treatment?

Trimethoprim comes in a 100mg and 200mg dosage, both of which are available at 121doc. The dosage needed will largely depend on the severity of your infection and whether you are using the medication as a long-term preventative treatment. As cystitis can be a recurring condition, Trimethoprim can be used to help reduce the risk of any potential infections developing.

The 200mg dosage of Trimethoprim is usually recommended in cases where the treatment is required for an existing infection. In these cases, one 200mg tablet should be taken twice a day for 14 days. You should take each tablet with a glass of water and you can take it with or without food. If you are using Trimethoprim as a preventative treatment against cystitis, the 100mg dosage will normally be prescribed. You should follow the instructions of your doctor in regards to how long the treatment should be continued for.

It is important that you take this medication as per the instructions. You should complete the course of antibiotics you have been prescribed, unless specifically told to do otherwise by your doctor. This means completing the prescribed course even if the cystitis symptoms that you were experiencing have cleared. You will be sent the patient leaflet along with your medication. This document will have full instructions on how and when to use this treatment. You are required to read this patient leaflet before starting your course of Trimethoprim.

Are there any side effects?

Trimethoprim is a widely used and well-tolerated medication and so the potential risk of side effects occurring is very small. If you do experience any, they can include vomiting, headaches and nausea. These side effects normally pass very quickly. Please contact your doctor if you experience any persistent side effects that cause you discomfort.

How to buy Trimethoprim online?

You can buy Trimethoprim online at 121doc by selecting your treatment and completing our quick and simple online medical questionnaire. Once completed, our doctors will review your details to make sure that Trimethoprim is the right treatment option for you. If approved, a prescription will be created and the medication dispensed from our UK registered pharmacy. We offer next day delivery to all of our customers at no extra cost.

Please note that the 100mg dosage is for continual use and 200mg is used for a recurrent bout.

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.


What is included in the online consultation?
Will a doctor review my consultation?
What happens after I submit my order?
Is the price all-inclusive?
Can I place more than one order at a time?
What are my delivery options?
Is it safe to buy prescription medication online?
How do I know which treatment is best for me?
Is this service discreet?
What is included in the online consultation?

Our consultations include general questions about your health (e.g. blood pressure levels, current and past conditions), as well as specific questions related to your selected treatment. We will also request relevant personal information to complete payment and delivery.

All questions are necessary, and your answers and details will not be shared with any third-parties. Only our doctors have access to your medical information.

Will a doctor review my consultation?

It is a legal and medical requirement that a doctor first reviews all completed consultations. We have a team of in-house doctors and specialists who will ensure your selected treatment is safe for your use. All information is stored securely and confidentially.

Please note, we do not guarantee that our doctors will approve treatment.

What happens after I submit my order?

Your consultation will be sent directly to our medical team, where it will be reviewed by one of our doctors.

If your chosen treatment is deemed suitable for your use, they will issue a prescription. Your prescription is then forwarded to our pharmacy, where your medication will be dispensed and dispatched for courier delivery.

Is the price all-inclusive?

Yes. All 121doc orders include a medical consultation, a prescription and next-day delivery. There are no additional costs. We believe in providing a safe and easy-to-use service.

Can I place more than one order at a time?

Yes. However, certain medications may negatively interact with each other. Our doctors may not approve your order on this basis.

You can place multiple items in one basket, and complete a consultation for all.

If you wish to place a second order for a different medication, you will have to complete a separate consultation.

What are my delivery options?

We offer several delivery options:

  • 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 available, a friend or relative can sign in your place.

None of these options will incur an additional charge.

Is it safe to buy prescription medication online?

To ensure you are purchasing from a reputable company, you should look to see their country’s regulatory bodies verify them.

In the UK, this is the Care Quality Commission (CQC) and the Medicines and Healthcare products Regulatory Agency (MHRA).Certificates can be viewed here.

How do I know which treatment is best for me?

Some treatments also offer the 'Advise Me' function. You will be asked questions about your lifestyle and needs, plus medical questions. You will then be presented with the advice of our doctors.

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 regularly inspected by various UK regulatory agencies, such as the Information Commissioner's Office (ICO).

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

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What others say about us

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How does it work?

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


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.


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


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.


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 Our doctors review your order.
Free prescription


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


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).


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

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


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


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).


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


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.


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.


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!