Medically reviewed by Angela Sheddan, FNP
Written by Our Editorial Team
Last updated 3/29/2022
Doxycycline is an oral antibiotic that works by preventing the growth of bacteria. In addition to treating infected acne, it’s also used to a range of other bacterial infections, including sexually transmitted infections (STIs), urinary tract infections (UTIs) and respiratory tract infections.
As a tetracycline antibiotic, doxycycline has been in use for decades. It’s generally a safe and effective medication. However, like other antibiotics, it can cause side effects.
Below, we’ve listed the most common side effects of doxycycline, as well as information about how each side effect may affect you if you’re prescribed this medication. We’ve also discussed the less common, more severe side effects and interactions associated with doxycycline.
Finally, we’ve explained what you need to know before using doxycycline, especially if you are pregnant or plan to become pregnant in the near future.
Doxycycline can cause side effects, some of which are quite common. These include digestive health issues, changes in your level of sensitivity to direct sunlight and a temporary increase in your risk of developing certain vaginal infections.
In clinical trials of doxycycline, between 40 and 53 percent of people reported experiencing one or more side effects during treatment. Side effect rates varied based on whether the medication was given as a single extended-release dose or in two separate doses.
We’ve listed these common side effects below, with information about how often each issue can occur and the symptoms you may develop if you’re affected.
Nausea is a common side effect of doxycycline. In trials of Doryx®, a brand of doxycycline, 13.4 percent of people reported developing nausea over a seven-day treatment period. While taking doxycycline, you may feel sick to your stomach and as if you are going to vomit.
Nausea is a common side effect of many antibiotics, not just doxycycline. To treat nausea, try to consume lots of fluids, eat bland meals and opt for smaller, more frequent meals over larger and less frequent ones. It may also help to avoid strong odors or fragrances.
Vomiting is also a common adverse effect of doxycycline, with 8.1 percent of people developing this side effect in clinical trials.
If you vomit often, you may become dehydrated. Signs of dehydration include a dry mouth, dark urine and an infrequent need to urinate. Make sure to keep yourself hydrated if you vomit while using doxycycline, as it’s important to replace any lost fluids.
Approximately two percent of people prescribed doxycycline report developing headaches while using this medication, according to clinical trial data.
If you develop a headache while using doxycycline, try to rest in a quiet space in your home and drink plenty of fluids to prevent dehydration. Placing a cool cloth on your forehead may help to dull the pain of the headache and make it easier to tolerate.
Doxycycline does not interact with over-the-counter pain medications such as ibuprofen (Advil®, Motrin®), acetaminophen (Tylenol®) or aspirin. These medications might help to provide relief if your headache doesn’t improve on its own.
If you’re prescribed doxycycline at a high dose, or if you have a history of liver health issues, it’s important to talk to your healthcare provider before using pain medication with doxycycline.
Diarrhea is a common side effect of antibiotics, including doxycycline. According to clinical trials, 3.3 percent of people who use doxycycline experienced drug-induced diarrhea at some point in the treatment period.
Antibiotics such as doxycycline may cause diarrhea by upsetting the natural balance of bacteria inside your digestive tract. In some cases, antibiotic use can lead to overgrowth of the bacteria Clostridioides difficile (C. diff), which can cause severe diarrhea.
If you experience diarrhea while using doxycycline, it’s important to keep yourself hydrated and talk to your healthcare provider. They may suggest using a supplement called a probiotic to add healthy bacteria to your digestive tract and prevent diarrhea.
Upper abdominal pain is a known potential side effect of doxycycline, with two percent of people reporting this issue in clinical trials. This may occur due to the digestive issues associated with doxycycline and other forms of antibiotic treatment.
For mild abdominal pain, try sipping on water or other clear fluids while restricting your intake of solid foods. Some foods and beverages, such as carbonated drinks, citruses, high-fat foods and beverages that contain caffeine, may make this pain more severe.
If you have recurrent or severe upper abdominal pain while using doxycycline, it’s best to talk to your healthcare provider.
Approximately 3.3 percent of people who used doxycycline in clinical trials reported developing bacterial vaginosis — a form of vaginal inflammation that’s caused by excessive growth of some forms of vaginal bacteria.
This side effect may occur as a result of doxycycline’s effects on certain types of bacteria, which may upset the bacterial balance in your vagina.
Although bacterial vaginosis affects your vagina, it isn’t a sexually transmitted disease. Tell your healthcare provider if you notice any signs of bacterial vaginosis, such as discharge or a strong odor from your vagina. They may prescribe topical antibiotics to treat this issue.
Vulvovaginitis is a form of swelling and/or infection that affects your vulva and vagina. It occurs in two percent of people who use doxycycline, according to data from clinical trials.
The most common cause of vulvovaginitis is yeast infection. Doxycycline and other antibiotics may increase your risk of developing a yeast infection by affecting the growth of healthy types of bacteria, allowing certain forms of fungus to multiply rapidly.
Vulvovaginitis may involve vaginal itching and irritation, inflammation, discharge and a foul odor from your vagina. Your healthcare provider may prescribe a cream or suppository that you can use to treat the infections that cause vulvovaginitis to develop.
One of the most significant side effects of doxycycline is photosensitivity, or an increase in your skin’s sensitivity to sunlight.
While taking doxycycline, you may notice that you become burned easily when you’re exposed to UV radiation from the sun. Even small amounts of exposure to sunlight may result in pain, itchy skin and severe sunburn.
To prevent sunburn, wear protective clothing and apply SPF 30+, broad-spectrum sunscreen to your skin while using doxycycline. Try to limit the amount of time you spend under bright, direct sunlight when outdoors by spending time in the shade whenever possible.
Doxycycline may also cause other side effects, including side effects that can be severe and/or persistent. Inform your healthcare provider if any of the side effects below are severe or do not improve over time:
Loss of appetite
Swelling of your tongue
Sore and/or irritated throat
Changes in your skin, nail, hair, eye or mouth color
In some cases, doxycycline can cause serious, potentially dangerous side effects and/or allergic reactions. Inform your healthcare provider as soon as you can if you notice any of the following side effects:
Blurred vision, double vision or vision loss
Hives, red skin, blisters or peeling skin
Rash accompanied by swelling of your glands and/or fever
Swelling that affects your eyes, face, lips, tongue or throat
Persistent watery or bloody diarrhea
Persistent stomach cramps and/or fever
Difficulty breathing and/or swallowing
Unusual bleeding and/or bruising
Discoloration of teeth
Chest pain and/or joint pain
Doxycycline side effects may develop at any time while you’re using this medication. Some side effects may continue after you stop treatment with doxycycline. If you have severe or persistent side effects, it’s important to talk to your healthcare provider.
Doxycycline is a widely-used medication, and it’s generally safe for most people when it’s used as prescribed. However, there are some safety issues, including possible drug interactions, that you should be aware of before using doxycycline.
Doxycycline can interact with other medications, including anticoagulant drugs, pain treatments such as methoxyflurane, barbiturates, anti-epileptics, antacids, iron supplements and some oral contraceptives, such as the birth control pill.
Using isotretinoin with doxycycline can cause a potentially dangerous condition called increased intracranial pressure (ICP), which may cause brain and spinal cord injury.
To avoid drug interactions, make sure to inform your healthcare provider about any medications, dietary supplements and herbal products you currently take or have recently taken before using doxycycline.
Doxycycline should not be used during pregnancy or breastfeeding. Taking doxycycline during pregnancy can harm your fetus. Using doxycycline while breastfeeding may affect child tooth development and cause permanent tooth discoloration.
Inform your healthcare provider if you are pregnant or plan to become pregnant in the near future before using doxycycline.
Doxycycline is available as a tablet, capsule and liquid. When sold in tablet or capsule form, it may be a delayed-release formulation.
Take doxycycline exactly as prescribed by your healthcare provider. You may need to take this medication one or two times per day. Take each dose doxycycline with a full glass of water. If you feel sick after using doxycycline, try taking it with a small meal or glass of milk.
Make sure to continue using doxycycline for the entire treatment period. Stopping doxycycline earlier than recommended can increase the risk of your acne or other bacterial infection coming back in the future.
Store doxycycline in its original container in a safe, secure location away from light, excess heat or moisture. Do not store doxycycline in the bathroom. Make sure to keep doxycycline and other medications out of reach of children.
If you’re prone to inflammatory acne, doxycycline is one of several medications your healthcare provider may recommend using to clear your skin and stop your acne from coming back.
Interested in learning more about fighting acne? Our guide to the causes of acne in adults goes into more detail about why acne breakouts develop in the first place, while our Acne Treatment uses a customized prescription formula to help you get rid of your acne for good.