Trimethoprim is an antibiotic that is used for the treatment of uncomplicated urinary tract infection (UTIs) like cystitis. Cystitis is usually caused by a bacterial infection irritating the bladder. Trimethoprim is an antibiotic that works by killing the bacteria within the urinary tract or bladder that cause the infection. It kills the bacteria by entering their cells and damaging their genetic material (DNA). This leaves the bacteria unable to repair themselves or to multiply and so clears up the infection.is an antibiotic used to treat urinary tract infections.
Trimethoprim works directly on the affected area traveling to the bladder. This is why it is recommended to take trimethoprim at night. It allows the medicine to remain in the bladder longer where it works effectively before leaving the body through the urine.
While most people see positive results from Trimethoprim, it is not 100% effective. Factors such as antibiotic resistance may mean that a course of Trimethoprim may not clear up your UTI. If Trimethoprim does not work for your UTI, you should speak to a doctor, who can recommend different treatments.
Trimethoprim is usually taken as one 200mg tablet twice daily for three days. Doses should be spaced 10 to 12 hours apart. Drinking alcohol while taking Trimethoprim is considered safe. It is recommended to avoid alcohol if possible as it may worsen cystitis symptoms and cause dehydration. Instead, you should drink plenty of water to flush out the bacteria caused by the UTI.
Trimethoprim usually improves UTI symptoms in as little as 24 hours although the full effect can take up to 3 days. If you feel your symptoms are not improving or getting worse, then you should speak to a doctor for continued treatment or alternative antibiotics, as it may mean the infection is more severe or the bacteria is resistant to Trimethoprim. It could also indicate that your symptoms are caused by something other than a bacterial infection, which requires investigation.
Make sure you finish your entire course of treatment, even if you do not have any symptoms. If you stop taking your treatment early then the bacteria may continue to grow, which means the infection will come back quickly. Stopping your antibiotic course early can lead to resistance to the antibiotic in the bacteria, known as antibiotic resistance.
Always use this medication exactly as your clinician has told you. Check with our clinical team or your GP or pharmacist if you are not sure.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
Side effects of Trimethoprim side effects include:
- Headaches
- Rashes
- Hives
- Nausea
- Stomach upset
- Thrush
- Vomiting
- Diarrhoea
For full information on side effects and correct use, see the patient information leaflet. If any side effects concern you, or you are experiencing any of the side effects mentioned in the patient information leaflet whilst taking this medication, please contact our clinical team or speak to your GP.
You should not use Trimethoprim if you have the following conditions:
- Kidney disease
- Liver disease
- Blood disorder such as folate deficiency
- Galactose intolerance, total lactase deficiency or glucose-galactose malabsorption
- Porphyria
- Blood disorders such as hyperkalemia
If you are pregnant or trying to fall pregnant, Trimethoprim is not suitable to use. It may cause harm to the baby, particularly during the first trimester. Consult your GP about your alternative antibiotic options for UTIs while pregnant.
If you are breastfeeding, a small amount of the medicine will pass into the breastmilk, potentially causing side effects in the baby. Consult your GP before using Trimethoprim while breastfeeding.
Get emergency medical help if you have signs of an allergic reaction to this medication. These include:
- Hives
- Dizziness
- Fast or pounding heartbeats
- Wheezing
- Difficult breathing
- Swelling of your face, lips, tongue, or throat.
It is important that you let us know which prescription, over-the-counter medicines and recreational drugs you are currently taking. You must also tell us about any other medical conditions that you currently have (or had in the past). This will help us ensure the prescribed medication is safe and appropriate for you to take.
For full information on warnings, medication interactions and contraindications, refer to the Patient Information Leaflet. Please read all packaging and the Patient Information Leaflet before taking any new medicine and inform our clinical team or your GP of medicines you are taking or intend to take.
