If you’ve ever had a yeast infection after taking antibiotics, you’ll know firsthand that the last thing you need after getting rid of one infection is for another one to show up soon after.
Taking antibiotics is actually one of the most frequent — and predictable — triggers for vulvovaginal candidiasis (VVC), aka a yeast infection. Nevertheless, researchers haven’t figured out why that happens, nor how to prevent it. Yet another thing we can blame on the gender health gap!
Antibiotics are a type of medication prescribed to treat many common bacterial infections, from UTIs to bacterial vaginosis (BV), so why are they putting people with vaginas at risk of yeast infections?
Let’s look at the available research (spoiler alert: there isn’t much) and explore how antibiotics can lead to yeast infections, what kind of antibiotics carry the highest risks, and what you can do about it.
Can antibiotics trigger a yeast infection?
Sadly, yes. The risk of getting a yeast infection after taking antibiotics is between 10-30%. All antibiotics can cause yeast infections, but there are a few factors that can determine your likelihood of getting a yeast infection after a course of antibiotics.
Having Candida already present in your vaginal microbiome can put you at a higher risk (33%) of developing a yeast infection after antibiotic treatment. Some research shows that having BV can increase your risk of developing a yeast infection after taking antibiotics, as well.
Moreover, vaginal application of antibiotics seems to carry the highest risk of yeast infections, especially with clindamycin and metronidazole, which are often prescribed to treat BV. Interestingly, tetracyclines (such as doxycycline) prescribed for long-term acne are also identified as a specific risk factor for Candida overgrowth. Because apparently wanting clear skin and no yeast infections is too much to ask!
Other variables that influence the risk of post-antibiotic VVC include:
Why do antibiotics cause yeast infections?
Vaginal infections happen when something upsets the natural balance in your vaginal microbiome, allowing pathogens to colonize and cause dysbiosis. This then leads to the onset of symptoms, like itching and unusual discharge.
The main theory explaining why antibiotics trigger yeast infections is that antibiotics wipe out protective bacteria like lactobacilli as well as the bad, leaving your vaginal microbiome more vulnerable to Candida overgrowth, the cause of yeast infections.
However, no study has proven this theory. A 2019 review on the link between antibiotics and yeast infections concluded that vulvovaginal candidiasis isn’t more common in women with lower levels of lactobacilli in their vaginal flora, nor that women with recurrent yeast infections have lactobacilli-deficient microbiomes.
The review suggests that rather than affecting lactobacilli, antibiotics may impact the vaginal microbiome by triggering the release of heat shock proteins and hindering the release of cytokines (protective chemicals), allowing Candida fungi to colonize. More research is needed to confirm this theory, though.
Can you prevent yeast infections caused by antibiotics?
There aren’t any official guidelines for preventing yeast infections caused by antibiotics.
Your doctor may suggest that you start treatment for yeast infection — usually an oral antifungal, like fluconazole — along with your antibiotic treatment — either if you start to experience symptoms, or prophylactically if you have a history of yeast infections. If you start experiencing symptoms of a yeast infection while taking antibiotics, check with your doctor before trying an OTC antifungal, because some antibiotics can react with other medications.
Similarly, some doctors believe that lactobacilli probiotic supplements — taken either orally or vaginally — can prevent yeast infections by replenishing the vaginal microbiome after a course of antibiotics. Unfortunately, there is minimal data to support this theory (but wouldn’t it be neat if it did?).
If you’ve been prescribed antibiotics by your doctor, it’s really important that you complete the full course. Yes, the looming threat of a yeast infection is a bummer, but stopping antibiotics means the infection you were treating could return. At the end of the day, having one infection is better than having two.
Fluconazole is an antifungal medicine. It's used to treat infections caused by different kinds of fungus.
The most common cause of fungal infections is a yeast called candida.
Fluconazole is used to treat many infections caused by candida including:
Fluconazole is also used to treat a brain infection called cryptococcal meningitis. This is caused by a fungus called cryptococcus.
Fluconazole can also be used to prevent a fungal infection developing. It is only prescribed if you are likely to get this sort of infection. This includes people who:
Fluconazole is available as capsules or a liquid that you swallow.
It also comes as an injection, but this is usually given in hospital.
Fluconazole is usually prescribed for you by a doctor. You can also buy it from a pharmacy for vaginal thrush or balanitis.
2. Key facts
3. Who can and cannot take fluconazole
Most adults and children can take fluconazole. It can also be prescribed for babies.
Fluconazole is not suitable for everyone. Tell a pharmacist or your doctor before taking it if you have:
4. How and when to take fluconazone
Follow the advice from your doctor. If you buy fluconazole in a pharmacy, follow the instructions that come with the medicine.
It's important to complete the course of medicine even if you feel better.
You can take fluconazole capsules and liquid with or without food.
Fluconazole capsules are either 50mg, 150mg or 200mg. Swallow the capsules whole with a drink of water. It is best to take your capsules at the same time each day.
The liquid usually comes in 2 different strengths:
Use the plastic spoon that comes with your medicine to measure your dose. Do not use a kitchen teaspoon, as this will not give you the right amount.
Dosage for capsules or liquid
These are the usual doses for adults:
For children, your doctor will work out the right dose depending on the infection and your child's age and weight.
If you take your fluconazole once every 72 hours, or once a week, it may help to use a calendar and mark the days when you need to take it.
What if I forget to take a dose?
If you forget a dose, take it as soon as you remember, unless it's nearly time for your next dose. In this case, just skip the missed dose and take your next one as normal.
Do not take a double dose to make up for a missed dose.
If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to remember your medicines.
What if I take too much?
Accidentally taking 1 or 2 extra doses is unlikely to harm you.
Urgent advice: Speak to your doctor or pharmacist now if:
5. Side effects
Like all medicines, fluconazole can cause side effects, although not everyone gets them.
Common side effects
These common side effects happen in more than 1 in 100 people.
Talk to your doctor or a pharmacist if these side effects bother you or do not go away:
Serious side effects
Serious side effects are rare and happen in less than 1 in 100 people.
Call a doctor immediately if:
Serious allergic reaction
It happens rarely but it is possible to have a serious allergic reaction (anaphylaxis) to fluconazole.
Immediate action required: Call 999 or go to A&E if:
You could be having a serious allergic reaction and may need immediate treatment in hospital.
These are not all the side effects of fluconazole. For a full list, see the leaflet inside your medicine packet.
You can report any suspected side effect to the UK safety scheme.
6. How to cope with side effects
What to do about:
7. Pregnancy and breastfeeding
Fluconazole and pregnancy
Fluconazole is usually not recommended in pregnancy. Some studies have found that taking fluconazole in pregnancy can harm your baby.
If you have thrush, ask your GP or midwife for advice about treatments. Your doctor will probably prescribe clotrimazole or a similar antifungal medicine. This may be as a cream or as a soft tablet (a pessary) that you put into your vagina.
If the thrush does not go away, they may prescribe a single dose (150mg) of fluconazole. They will discuss the risks and benefits to you and your baby.
If the fungal infection is more serious, your doctor may recommend a higher dose of fluconazole, if it is the best treatment option. Talk to them about the risks and benefits to you and your baby.
Read more on the Best Use of Medicines in Pregnancy (BUMPs) website about taking fluconazole to treat thrush (150mg tablet) or high dose fluconazole (400mg to 800mg a day).
Fluconazole and breastfeeding
If your doctor or health visitor says your baby is healthy, you can use fluconazole when you're breastfeeding. Breastfeeding will benefit you and your baby.
If you notice that your baby is not feeding as well as usual, or seems unusually sleepy, or if you have any other concerns about your baby, then talk to your health visitor or doctor.
Non-urgent advice: Tell your doctor if you're:
8. Cautions with other medicines
Some medicines and fluconazole interfere with each other.
Tell your doctor if you are taking any of these medicines before you start taking fluconazole:
These are not all the medicines that interfere with fluconazole. For a full list, see the leaflet inside your medicines packet.
Mixing fluconazole with herbal remedies and supplements
There's very little information about taking herbal remedies and supplements with fluconazole.
Tell a pharmacist or doctor if you are taking any other medicines, including herbal medicines, vitamins or supplements.
9. Common questions
How does fluconazole work?
Fluconazole works by killing the fungus (or yeast) that is causing the infection.
The medicine kills fungus by making holes in its cell membrane, so that the contents leak out. This treats the infection and allows your symptoms to get better.
If you are taking fluconazole to prevent an infection, the medicine kills any fungus as it starts to appear.
How long does it take to work?
Fluconazole is used for many different fungal infections.
If you have vaginal thrush, balanitis or oral thrush, your symptoms should be better within 7 days of taking fluconazole.
If you have a serious fungal infection, ask your doctor how long it will take for fluconazole to start to work. It may be 1 to 2 weeks before it reaches its full effect.
What if it does not work?
Talk to your doctor if your symptoms do not improve after 7 days of taking fluconazole for vaginal thrush, balanitis or oral thrush.
Your doctor may ask you to take fluconazole for longer, or they may prescribe a different antifungal treatment.
If your symptoms get worse at any time, speak to your doctor.
How long will I take it for?
It depends on why you're taking fluconazole and whether your infection is getting better.
It could be a single dose, or treatment for several weeks, months or even years.
If your doctor prescribes a course of fluconazole, they will advise you how long to take it for. Keep taking your medicine until the course is finished, even if you start to feel better. This will help to stop the infection coming back.
Speak to your doctor if you want to stop taking it for any reason.
Is fluconazole safe to take for a long time?
You usually take fluconazole for a short time to clear an infection.
If you have a serious infection, you may need to take fluconazole long term. It is safe to take for a long time if your doctor has advised you to.
If you take fluconazole long term, your doctor may ask you to have regular blood tests.
Are there other medicines for fungal infections?
There are many different antifungal medicines. Some are available to buy from a pharmacy, others are available on prescription.
They can come as creams, gels, sprays, pessaries (soft tablets you put into your vagina), tablets, capsules, liquid, or injections.
Your doctor or a pharmacist will be able to recommend the best treatment for you, based on your condition.
Antifungal medicines include:
Will it affect my contraception?
Fluconazole is not likely to affect your contraception, including the combined pill or emergency contraception.
If taking fluconazole makes you vomit or have severe 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.
Find out what to do if you're taking the pill and you're being sick or have diarrhoea.
There have been some reports of "breakthrough bleeding", known as spotting, when people take fluconazole and the combined pill together. It is not known whether this is to do with the fluconazole. If you get any breakthrough bleeding while using oral contraception, speak to your doctor.
Some studies have shown that there is a small chance that fluconazole could increase the levels of hormones in your body when using the combined pill. You can continue taking fluconazole with your oral contraception, but if you get any side effects, such as feeling sick or tender breasts, speak to your doctor.
Will it affect my fertility?
There is no clear evidence to suggest that fluconazole will reduce fertility in either men or women.
Can I drink alcohol with it?
You can drink alcohol while taking fluconazole.
Is there any food or drink I need to avoid?
No, you can eat or drink normally while taking fluconazole.
Can I drive or ride a bike?
Yes, you can drive or ride a bike while taking fluconazole.
In rare cases, taking fluconazole can make you feel dizzy or lightheaded. If you're affected, do not drive or cycle until this feeling goes away.
Can I take fluconazole after amoxicillin?
No interactions were found between amoxicillin and Diflucan.
Can I take antifungal and antibiotic at the same time?
It is common in clinical practice the use of antibiotics and antifungals simultaneously or sequentially.
How long after taking antibiotics can you get a yeast infection?
Since antibiotics are used to kill off harmful bacteria in the body, they can also destroy healthy bacteria in the process. This can lead to a vaginal yeast infection that may occur during your course of antibiotics, or for a period of weeks afterward while there is still an imbalance of beneficial bacteria.
What should I take for yeast infection after antibiotics?
Taking an antifungal medication for three to seven days will usually clear a yeast infection. Antifungal medications — which are available as creams, ointments, tablets and suppositories — include miconazole (Monistat 3) and terconazole.