Understanding Antibiotics and Yeast Infections

Highlights from this article

• Antibiotics are one of the most common triggers for yeast infections, but researchers don’t know why. 
• The main theory is that antibiotics kill the good bacteria in your vaginal microbiome, but no studies prove this. 
• The type of antibiotic, length of treatment, route of administration, and a pre-existing presence of Candida all influence the risk of developing a yeast infection after a course of antibiotics. 
• There’s no proven way to prevent a yeast infection after taking antibiotics. Current options include antifungals or probiotics in conjunction with antibiotics. 

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: 

• Whether or not you’ve had antibiotic-induced yeast infections in the past
• Having a susceptibility to yeast infections
• Existing vulvar diseases, like lichen sclerosus  
• The type of antibiotic (broad-spectrum antibiotics carry the highest risk)
• Taking estrogen therapy or steroids

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. 

FAQs

How can I prevent a yeast infection while taking antibiotics?

The benefits of antibiotics are way more significant than the risk of side effects. Although antibiotics can put you at risk of a yeast infection, not taking antibiotics can make a bacterial infection that much harder to treat. Unfortunately, there aren't any official guidelines for preventing yeast infections caused by antibiotics. Your healthcare provider might suggest starting treatment for a yeast infection, usually with an oral antifungal like fluconazole, alongside your antibiotic treatment. Some doctors believe that taking Lactobacilli probiotic supplements, either orally or vaginally, can prevent yeast infections by replenishing the vaginal microbiome after a course of antibiotics, but there's not a lot of data to support this. If you notice symptoms of a yeast infection while taking antibiotics, it's best to check with your doctor before trying an over-the-counter antifungal, as some antibiotics can interact with other medications.

How long does yeast infection last after antibiotics?

A yeast infection caused by antibiotics can last anywhere from a few days to a couple of weeks, depending on how quickly you start treatment and how your body responds. If you treat it promptly with an over-the-counter antifungal medication, the infection usually begins to improve within a few days and should clear up completely within a week. However, if left untreated, the infection can last longer. If symptoms continue for more than a week after starting treatment or if they worsen, it's a good idea to consult a healthcare provider for further evaluation and possible alternative treatments. 

How can I naturally flush out a yeast infection?

There are no proven ways to “flush out” a yeast infection naturally. Most home remedies you see floating around online are largely ineffective and can cause more harm than good. The only proven way to treat yeast infections is by taking over-the-counter or prescription antifungal medication like fluconazole, terconazole, or miconazole.

Can antibiotics cause vaginal discharge?

Yes, sometimes antibiotics can cause changes in vaginal discharge. This happens because antibiotics, while effective at killing harmful bacteria, can also disrupt the balance of normal, healthy bacteria in the vaginal microbiome. When the balance is disrupted, it can lead to an overgrowth of yeast, specifically Candida, resulting in a yeast infection. One of the most common symptoms of a yeast infection is a change in vaginal discharge — typically thick, white, and "cottage cheese-like." If you notice unusual discharge after starting antibiotics, it might be a sign of a developing yeast infection, and you may need an antifungal treatment to address it.