Trimethoprim is a type of broad-spectrum antibiotic which was a common treatment for urinary tract infections (UTIs), including cystitis. But, recent clinical guidelines from NICE say that the number of UTIs treated with trimethoprim have caused antibiotic-resistant bacteria.
So, trimethoprim is no longer recommended as a treatment for cystitis and other treatments should be used instead. If you’re looking to order cystitis treatment from us, ZAVA offers other recommended treatments, like nitrofurantoin (Macrobid).
6 tablet(s) - £18.00
The active ingredient has the same name as the medication, ‘trimethoprim’.
- Lactose monohydrate
- Sodium starch glycollate (type A)
- Magnesium stearate
Common side effects
- Skin rashes
- Sore throat
- Mouth ulcers
- Irregular heartbeat caused by high levels of potassium in the blood
Until recently, trimethoprim was regularly prescribed for treating urinary tract infections in the UK. But because of increased antibiotic resistance, new guidelines say that others treatments should usually be used instead. 34% of UTI samples now show bacteria that are resistant to trimethoprim.
Trimethoprim is still occasionally used to treat some other infections, like:
- Skin infections
Guidelines say that instead of prescribing trimethoprim for cystitis or urinary tract infections, other treatments should be used. Nitrofurantoin is another cystitis treatment, where only 3% of UTI samples are resistant. This means it’s much more likely to be effective than Trimethoprim.
You can order Nitrofurantoin from ZAVA with a service that’s quick and easy to use – just follow these simple steps:
- Fill out a short online assessment about your health and lifestyle
- Place an order for your preferred treatment option
- Your assessment will be checked to see if your order is right for you
- If approved, your order can then be posted to your preferred address or you can collect it from a local post office instead
Nitrofurantoin is effective at treating urinary tract infections because it’s filtered out of the blood by the kidneys and then into the urine. So, the medication is able to come into contact with the bacteria causing the infection.
Nitrofurantoin enters bacteria cells and damages their DNA, so they are not able to repair themselves or multiply, which helps get rid of the infection. If you get repeat UTIs, you may be prescribed nitrofurantoin for a longer period of time to control the bacteria numbers in your urine and prevent the infection from coming back.
Trimethoprim is an antibiotic which works by stopping bacteria from producing something called folate. Without folate, bacteria cannot produce DNA and without DNA, they’re not able to grow and multiply.
By preventing bacteria from multiplying, trimethoprim stops the spread of infection, leaving the left over bacteria to be killed off by the body’s immune system.
You usually shouldn’t take trimethoprim for cystitis, but it might be prescribed to you for treating some other infections. If you’ve had a urine sample culture which shows your specific infection is not resistant to trimethoprim, and there are medical reasons you can’t take nitrofurantoin, you may still be given trimethoprim for cystitis.
The dosage of trimethoprim you’ll need to take and how long your treatment will last for depends on the type of infection it’s being prescribed for. But, for sudden infections in adults and children over the age of 12, doctors usually prescribe 200mg, taken twice a day. If it’s a long-term treatment, or it’s being used for preventing infections, the dosage is usually 100mg, at night only.
For older people, the dosage can be different according to each person’s kidney function. If an older person has kidney problems, they’ll usually be prescribed a lower dosage.
You should always take trimethoprim exactly as it’s prescribed to you and if you’re not sure how to take it, you should check with a doctor or pharmacist. You should swallow the tablet whole with a glass of water, at the same time each day. Trimethoprim tablets shouldn’t be chewed.
Other doses include:
- 100mg one-off dose to treat cystitis which comes on after having sex
- 300mg twice a day to treat acne
There’s no research that says you can’t drink alcohol while taking trimethoprim. Alcohol doesn’t change the effects of trimethoprim. But, if you get side effects, like an upset stomach or a headache, you should avoid drinking alcohol because it can make these symptoms worse.
If you’re pregnant, thinking about getting pregnant, or breastfeeding, you should ask your doctor or pharmacist for advice before taking trimethoprim.
You shouldn’t take trimethoprim while you’re pregnant because it can lead to a folic acid deficiency. A lack of folic acid during pregnancy increases the risk of your child getting neural tube defects, like spina bifida. So, taking trimethoprim during pregnancy can seriously affect the development of your baby’s brain and spine.
If you’re breastfeeding, it’s usually safe to take trimethoprim. Even though trimethoprim can be passed on to babies through breast milk, this will only happen in small amounts, so short-term use doesn’t usually cause any harm.
Trimethoprim isn’t right for everyone and you should tell your doctor if you:
- have ever had an allergic reaction to any medications in the past, particularly trimethoprim
- have liver or kidney problems
- are trying to get pregnant, or you’re already pregnant
- have a blood disorder, including porphyria
- have anaemia
Uncommon and rare side effects include:
- watery or bloody diarrhoea
- abnormal behaviour
- aseptic meningitis, which can cause symptoms including: headache, stiff neck, fever, tiredness, and sensitivity to light
- kidney problems
- involuntary movements
- pins and needles
- ringing in the ears
- eye pain and redness
- low blood sugar
- low blood sodium levels
- difficulty sleeping
- joint and muscle aches
- shortness of breath
If you get any of the following symptoms, you should stop taking trimethoprim right away and get emergency medical attention:
- Difficulty breathing
- Chest pain
- Swelling of face, lips, tongue, and throat
- Blistering/peeling skin
- Skin Lesions
- Deep swelling of the skin
- Pancreatitis, which might cause severe upper abdominal pain
Dr Nicholas Antonakopoulos
Dr Nicholas Antonakopoulos graduated from the University of London in 2006. He did his postgraduate training in hospitals in the London area, and he trained for four years in Trauma and Orthopaedic Surgery before completing his training in General practice in 2015.Meet our doctors
Last reviewed: 03 Apr 2019
Athlone Laboratories Limited (2017). Trimethoprim 100mg and 200mg tablets. [online] Available at: https://www.medicines.org.uk/emc/files/pil.5925.pdf [accessed 18 March 2019].
Crellin, E. et al (2018). Trimethoprim use for urinary tract infection and risk of adverse outcomes in older patients: cohort study. BMJ, Jan; 360. [online] Available at: https://pubmed.ncbi.nlm.nih.gov/29438980/ [accessed 13th May 2021]
NHS (2018). Trimethoprim. [online] Available at: https://www.nhs.uk/medicines/trimethoprim/ [accessed 18 March 2019].
NICE (2017). Antibiotic resistance is now “common” in urinary tract infections. [online] Available at: https://www.nice.org.uk/news/article/antibiotic-resistance-is-now-common-in-urinary-tract-infections [accessed 18 March 2019].