Cystitis (UTI)

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  • Trimethoprim


Cystitis (UTI)
  • Medication features

    Trimethoprim is an antibiotic used to treat urinary tract infections. It is usually given as a 7-day course of treatment (for men). It is important to complete the course you are prescribed even if you feel your symptoms subsiding.

    • Used to treat urinary tract infections
    • Prescribed as a 7-day course
    • One tablet to be taken twice a day 


NOTE: After selecting this product, you will need to complete a short assessment, so we can make sure this medication is suitable for you. Pricing is provided as a reference only. The final decision on issuing this medication remains with our Prescriber / Pharmacist.

Trimethoprim is an antibiotic typically used to treat urinary tract infections, such as cystitis. It should help to relieve any symptoms within a few days.


  • How long will it take to work?

    Your symptoms should typically start to improve within 24 hours and should have gone after three days of treatment. If you no longer have symptoms, you should ensure that you complete the course to prevent the infection reoccurring.

    If you still have symptoms or your symptoms have worsened after completing the course of Trimethoprim you should contact your doctor.

  • Is it safe to use Trimethoprim continuously?

    It is not recommended to take Trimethoprim regularly with speaking to your doctor. If you are experiencing recurrent urinary tract infections, you should contact your doctor.

  • How can I manage side effects?

    Side effects like diarrhoea can be reduced by using over the counter treatments such as loperamide. Nausea can be prevented by taking Trimethoprim with or just after food. There are options available for vomiting such as cyclizine, promethazine, and prochlorperazine, which can be purchased here at Pharmacy Online.

  • Can I drink alcohol while taking this medication?

    Trimethoprim is not directly affected by alcohol; you can drink alcohol whilst on this medication.

    It is important to remember that alcohol acts as a diuretic and may cause the Trimethoprim to be flushed out of the system quicker; this may result in the course being less effective. It is therefore recommended to drink in moderation. 

  • What should I do if I miss a dose?

    If you have forgotten to take a tablet, take one as soon as you remember if it has been less than 24 hours since you took your last tablet. You should then resume taking Trimethoprim as normal.

    If more than 24 hours have passed since you took your last tablet, take your next tablet at the next scheduled time and taken as directed.

    You must remember to take Trimethoprim regularly as directed and to ensure you complete the course as failing to do so could prolong the infection.

  • Should I take Trimethoprim with food?

    Trimethoprim can be taken with or without food. It is however recommended to take Trimethoprim with plenty of water.

Side Effects

As with all medications, side effects are common and should subside with time. Should you be worried about any of the side effects associated with trimethoprim, please contact your GP or a member of our team. Side effects include:

  • Nausea
  • Itching or mild rash
  • Headaches
  • Diarrhoea

If you experience any of the below side effects, you should stop taking the medication immediately and contact a healthcare professional:

  • Unexplained bruising or bleeding
  • Muscle weakness
  • Diarrhoea containing blood
  • Chest pain
  • Symptoms of a serious allergic reaction such as swelling of the tongue, trouble breathing or talking, or tightness of the chest


Info Leaflet

Before taking any medicines, regardless of whether they are over the counter or prescription-only, it is essential always to read the patient information