Urinary tract infections (UTIs)

A pharmacist's guide to UTIs: what the evidence supports, what it doesn't, and what to ask for.

"Urinary tract infection" is a term that covers everything from a bladder infection that will usually settle in a few days to a kidney infection that requires more urgent investigation and treatment. Grouping them all together is why so much UTI advice can feel all over the place in terms of what to do and urgency to do it in.

Cystitis is a bladder infection, and it's what most people mean by a UTI. Bacteria travel up from the bowel, through the urethra, and stop at the bladder.

If the bacteria moves up into the kidneys it is known as pyelonephritis, and it is sometimes incorrectly referred to as a "worse case of cystitis." It is a completely different situation to cystitis and needs to be treated differently with more urgency. The symptoms that tell you the infection has moved up into the kidneys will be covered further down the page and are worth a look at.

Women get UTIs far more often than men, mainly due to the fact women have a shorter urethra which means a shorter journey for bacteria. It has nothing to do with their hygiene. Wiping technique, showering habits and how careful you are do not explain why some women get recurrent UTIs and others never do.

When men get UTIs it's less often about anatomy and more often about the bladder not emptying properly, which is why a UTI in a man is treated as something more serious to investigate rather than just treat. Same for anyone with a catheter, anyone pregnant, and anyone who keep getting constant infections.

For women under 65, UKHSA and NICE guidance narrow the symptoms down to three: dysuria (burning pain passing urine), new nocturia (getting up to pass urine at night more than usual), and urine that is cloudy to the naked eye. Two or more of these makes a UTI diagnosis more likely. New nocturia only counts if it's a change for you. Established nocturia from an existing bladder problem is not counted as a symptom.

If you've got all three symptoms, there's about an 82% chance you've genuinely got a UTI. Two symptoms puts you at around a 74% chance. Just one symptom puts you at around 68% chance. So a single symptom doesn't put you in the clear or mean you haven't got a UTI. It just means you can't be certain. 

Some confusion comes from the fact that certain symptoms are not enough to diagnose a UTI on their own. Strong-smelling urine, for example, is often caused by concentrated urine and can simply be a sign of dehydration. Urgency, needing to pass urine more often, visible blood in the urine and pain above the pubic bone are all symptoms worth taking seriously, but individually they do not clearly point to a UTI.

The clearest sign that it might not be a UTI you are dealing with is whether there's any vaginal discharge or irritation alongside the urinary symptoms. If there's discharge or irritation, a UTI becomes much less likely.

Thrush and bacterial vaginosis both cause stinging when you pass urine, but the stinging is external, as urine passes over sore skin, rather than the deep burning of cystitis. Thrush usually brings itching and thick white discharge. BV brings a thin grey discharge and a noticeable smell that's often worse after sex.

Chlamydia and gonorrhoea can cause urethritis, which feels close to a UTI and is easily mistaken for one. This matters most if you're sexually active and under 30, or if you have a new partner, a a sexual health clinic may be more appropriate than a pharmacy as testing for a sexually transmitted infection may be needed.

After the menopause, falling oestrogen thins the tissue of the vagina and urethra, which can produce burning, urgency and frequency with no infection present at all. It gets treated as recurrent UTI more often than it should be.

If you keep getting cystitis-like symptoms but urine tests repeatedly come back clear, it is worth looking into the cause rather than simply having another course of antibiotics. Ongoing bladder pain with repeatedly negative urine cultures may suggest bladder pain syndrome, which is managed differently from a UTI.

Dipsticks only moderately improve diagnostic accuracy, but they are poor at ruling infection out, and a negative result does not reliably mean you're clear. So if a dipstick comes back clean when you still feel unwell I wouldn't rule a UTI completely out.^[2]

If you're a woman aged 16 to 64 and this is a one-off bladder infection, your local high street pharmacy can very likely assess and treat you today, for free, on the NHS. No GP appointment, and usually no need to book beforehand.

Check before that they offer the NHS Pharmacy First service. The pharmacist will ask you about your symptoms, and how severe they are. If suitable they can supply a three-day course of nitrofurantoin under a patient group direction, alongside self-care advice.

We offer this at our Lower Alt Road pharmacy. If there's a pharmacy near to you it is worth calling or visiting them. It will be quick, it will cost you nothing (unless a course is offered and you pay for prescriptions).

The service does have strict boundaries so if you're pregnant, have a urinary catheter, have a fever, are vomiting, have kidney pain, or have had recurrent UTIs, meaning two episodes in the last six months or three in the last twelve. It would be better to call your GP instead.

Similar schemes run in Scotland and Wales under different names, so it's worth asking your local pharmacy wherever you are in the UK.

A lot of people assume one is "stronger" than the other, usually because they are prescribed one e.g. nitrofurantoin which doesn't clear up their infection, and then are given trimethoprim which clears it up, so they incorrectly assume that trimethoprim (or vice versa if they were given them the other way) is stronger than the other. What actually matters is whether the bacteria causing the infection are sensitive or resistant to the particular antibiotic used.

UKHSA surveillance found that in 2024, 2.2% of E. coli urinary isolates in England were resistant to nitrofurantoin, compared with 30.1% for trimethoprim. This is one reason nitrofurantoin is commonly used first for uncomplicated lower UTIs in the UK and why NICE only recommends trimethoprim as a first-choice treatment where the risk of resistance is considered low, or after a swab has been taken.^[3]

Even when a UTI is likely, antibiotics aren't always prescribed instantly. Mild symptoms in an otherwise healthy woman often settle on their own. When English pharmacies logged over 100,000 women with urinary symptoms, 94% were given self-care advice.

If you are offered pain relief, fluids and a plan to come back if things worsen, that isn't you being fobbed off, it is good advice and may save you needing to take a course of antibiotics.

If you have been prescribed antibiotics, it is likely you will only be given a three day course, quite a few women will ask where the rest is, or if three days is long enough to treat their UTI. NICE found that short (3-day) courses for treating uncomplicated lower UTI in non-pregnant women are sufficient and also minimise the risk of adverse events and of antimicrobial resistance. It is important you finish the course if you are prescribed them.

If you are taking an antibiotic and find your symptoms worsen rapidly or significantly, or do not start to improve within 48 hours you should contact your GP as you will likely need reassessed and a potentially a different antibiotic prescribed.

Painkillers.

Paracetamol or ibuprofen taken regularly will help with any pain you are experiencing. Ibuprofen isn't right for everyone, so speak to a pharmacist before taking it especially if you've been told to avoid anti-inflammatories for stomach, kidney or asthma reasons.

Heat.

A heat patch, hot water bottle or wheat bag against the lower abdomen is effective for the cramping ache.

Drink plenty of water.

This doesn't mean you have to go and drink litres and liters just drink enough so that you regularly pee during the day and do not feel thirsty.

Avoid alcohol, sugar and caffeine

Cutting out caffeine and alcohol for a few days may help, as both are bladder irritants, and can cause you to go to the toilet more often. The NHS recommends you also cut down on sugary food or drinks, as they may encourage bacteria to grow.

Cystitis sachets.

A Cochrane review looking for randomised trials of urinary alkalisers for symptomatic relief in uncomplicated UTI concluded that their safety and efficacy remains unknown. Alkalising the urine has been reported to reduce pain and frequency, but systematic analysis finds the evidence of effectiveness lacking.

This doesn't mean they are useless and plenty of women find they help, it does mean that nobody has properly tested them. If they've worked for you before, then carry on with them. If you're deciding what to spend money on for the first time, spend it on painkillers instead they are more likely to work.

These products can contain significant sodium or potassium, which matters if you've been told to watch your salt intake, if you have kidney problems, or if you're on medication that raises potassium. If you're taking methenamine hippurate, alkalinising sachets should not be used alongside it, because they make it less effective.

If you are suffering with two infections in six months, or three in a year you are classed as having recurrent UTIs. It is quite common in women and around 30 to 40% of women go on to have recurrent UTIs after a single episode.

You may need to book in with your GP and have a urine sample which is sent for culture. Treating recurrent infections empirically, over and over, without ever knowing what's actually growing or what it's sensitive to, is how people end up cycling through antibiotics that were never going to work.

Take a look at whether anything is making it more likely. Incomplete bladder emptying when you go to the toilet, contraception involving spermicide or a diaphragm, and a drop in oestrogen after the menopause can all make you more prone to UTIs.

Drinking water can help prevent UTIs but it is important to look at the evidence behind it first and what the research actually tells us, as many websites simply say "drink lots of water" and that doesn't tell us the full story. Hooton and colleagues randomised 140 premenopausal women with at least three episodes in the past year to drink an extra 1.5 litres of water daily or make no change, and followed them for 12 months. The water group averaged 1.7 episodes of cystitis against 3.2 in the control group, and used roughly half as many antibiotic courses, 1.9 against 3.6. The average gap between infections stretched from 84 days to 143.^[6]

So this isn't to say go and drink your body weight in water, everyone in that trial was drinking less than 1.5 litres of fluid a day to begin with. The finding is that women who were drinking very little benefited from drinking more. It is not evidence that someone already drinking two litres should increase it further. If you know you barely drink during the day, increasing your water intake is something you should do, but if you're already well hydrated, drinking more is unlikely to do anything except make you wee more.

Wipe front to back. Pass urine after sex. Avoid bubble baths. Don't wear tight underwear. Change out of wet swimwear. Doing these isn't harmful so there's no reason to stop if you're already doing it. But it's important to note that the evidence that any of it prevents recurrent UTIs is thin, and it gets presented with a confidence the research doesn't support. So if you suffer with recurrent UTIs and have been doing every single one of these things scrupulously for years and are still getting infected, you are likely not doing something wrong. Recurrent UTIs are mostly about anatomy, hormones, genetics and unfortunately luck, and no amount of careful wiping overrides that.

If your infections started or worsened around the menopause, it could be due to your vaginal oestrogen levels. Lower oestrogen changes the tissues around the vagina and urinary tract, reduces protective bacteria and makes the vaginal environment less acidic. NICE recommends considering vaginal oestrogen for recurrent UTIs during or after the menopause when behavioural measures have not been enough. Very little is absorbed into the bloodstream, and serious side effects are rare. It can also improve related symptoms such as vaginal dryness, soreness or discomfort. Oral oestrogens taken for up to four years were found to not significantly reduce recurrent infection risk in postmenopausal women. So immediately hopping on HRT medication is not the answer to recurrent UTIs. Vaginal oestrogen, applied locally, can help prevent further infections and if you have gone through the menopause and are suffering I would recommend booking in with your GP to discuss this.

If your infections reliably follow something specific, most often sex, NICE suggests considering single-dose antibiotic prophylaxis taken after exposure to an identifiable trigger, once any current infection has been properly treated. One tablet occasionally will keep you at low exposure and risk of adverse effects, rather than taking an antibiotic daily.

Hipprex or methenamine hippurate turns into formaldehyde in acidic urine, which makes the bladder an unwelcoming place for bacteria without driving resistance. This is a prescription only medication and needs monitoring as you take it, if you have tried everything you can, booking in with your GP to discuss methenamine hippurate is worth doing.

A GP may consider a trial of a low-dose antibiotic taken every day when recurrent UTIs continue despite other suitable preventive options. A Cochrane review found that, during 6 to 12 months of antibiotic prophylaxis, 12.3% of non-pregnant women had a microbiologically confirmed recurrence, compared with 65.5% taking a placebo. This gave a number needed to treat of 2, meaning that about two women needed to receive prophylaxis to prevent one from having a recurrence during treatment. The benefit did not appear to continue after prophylaxis was stopped, although this part of the evidence came from only two studies and was much less certain. Antibiotics therefore seem to prevent or suppress infections while they are being taken rather than permanently removing the factors that make someone prone to recurrent UTIs. Some women may begin having infections again after stopping.^[9]

D-mannose is a sugar that's supposed to stop E. coli sticking to the bladder wall. It's been a standard suggestion for recurrent UTIs for years, and it sells in many supplement stores for up to £23 a month in the UK.

In 2024 MERIT recruited 598 women with recurrent UTI across 99 UK primary care centres, randomising them to daily D-mannose or placebo over six months. During the study, 51.0% of the D-mannose group contacted a healthcare professional with another suspected UTI, against 55.7% on placebo. The difference wasn't statistically significant. D-mannose also did not significantly improve the other outcomes measured, including laboratory-confirmed UTIs, symptoms, antibiotic use or the time until the next UTI.

The authors' conclusion was that D-mannose should not be recommended to prevent future UTIs in women with recurrent UTI in primary care.The NIHR summary carries a quote from one of the trial's commentators saying he would now tell postmenopausal women with recurrent UTIs that it's probably not worth taking. ^[7]

Cranberry has better evidence behind it than many other UTI supplements, although any benefit appears to be modest and relates to prevention rather than treatment. Cranberries contain compounds called proanthocyanidins, or PACs, which may make it harder for some E. coli bacteria to attach to the urinary tract.

A 2023 Cochrane review included 50 randomised trials involving 8,857 people. Among women with recurrent UTIs, eight trials involving 1,555 women found that cranberry products reduced the risk of a symptomatic, culture-confirmed UTI by around 26% compared with placebo or no treatment.^[8]

This was a relative reduction and does not mean that cranberry will prevent one in every four infections. The studies used different juices, capsules, strengths and treatment periods, and the researchers could not establish which product or dose works best. It also did not show clear benefits in pregnant women, elderly people living in institutions or adults who had difficulty emptying their bladder. So if you're buying cranberry for an elderly relative in a care home, the evidence doesn't support it. If you're a woman under 65 with recurrent infections, it may help but do not take it during an existing UTI expecting to replace or work as well as antibiotics.