How does trimethoprim work?
Trimethoprim is an antibiotic that kills bacteria by stopping them making a substance called folic acid, which they need to survive.
This is why trimethoprim can sometimes cause low folic acid levels in your blood over time.
When will I feel better?
You should feel better within a few days.
It's important that you keep taking trimethoprim until your course is finished, even if you feel better. It will help stop the infection coming back.
Tell your doctor if you do not start feeling better after taking trimethoprim for 2 days, or if you start to feel worse at any time.
Will it give me thrush?
Some people get a fungal infection called thrush after taking a course of antibiotics like trimethoprim.
It happens because antibiotics kill the normal harmless bacteria that help to protect you against thrush.
Ask your pharmacist or doctor for advice if this happens to you.
Will it affect my contraception?
Trimethoprim does not stop any type of contraception from working, including the combined pill, progestogen-only pill and emergency contraception.
But if trimethoprim makes you sick or have severe, watery diarrhoea, or any diarrhoea for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.
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Can I drive or ride a bike?
Yes. Trimethoprim should not affect you being able to drive or cycle.
Is there any food or drink I need to avoid?
You can eat and drink normally while taking trimethoprim.
Can lifestyle changes help urinary tract infections?
Urinary tract infections (UTIs) are usually treated with an antibiotic, or it could spread to the kidneys and lead to more serious problems.
Once treated, there are many steps you can take to stop urinary tract infections coming back:
- Avoid perfumed bubble bath, soap or talcum powder around your genitals – use plain, unperfumed products, and have a shower rather than a bath.
- Go to the toilet as soon as you need to pee, and always empty your bladder fully.
- Stay well hydrated – aim to drink 6 to 8 glasses of fluid a day (water, lower fat milk and sugar-free drinks, including tea and coffee, all count).
- Wipe your bottom from front to back when you go to the toilet.
- Empty your bladder as soon as possible after having sex.
- Do not use a contraceptive diaphragm or condoms with spermicidal lubricant on them – use another type of contraception instead.
- Wear underwear made from cotton, rather than synthetic material like nylon.
- Avoid tight jeans and trousers.