Medically reviewed by Mary Lucas, RN
Written by Our Editorial Team
Last updated 3/20/2022
Doxycycline is a common antibiotic that’s available as a capsule, a tablet and as a suspension (liquid) that’s taken by mouth. It belongs to a class of versatile, widely-used medications called tetracycline antibiotics.
If you’ve gone to your doctor for help with acne, a skin infection or one of many other problems, you may have been prescribed doxycycline. Naturally, you may also have questions about what it is and how it works.
Below, we’ve explained what doxycycline is, as well as the specific conditions it’s prescribed to treat.
We’ve also shared a few things that you’ll want to know when using doxycycline, from potential side effects to interactions, safety and more.
Doxycycline is a tetracycline antibiotic. It works by killing certain types of bacteria and stopping bacterial infections from spreading through your body.
From a more technical perspective, doxycycline works by stopping the production of essential proteins that certain types of gram-positive and -negative bacteria need to multiply and spread inside your skin, chest and other parts of your body.
When you use doxycycline, bacteria stop being able to multiply. This can reduce the severity of many bacterial infections and, with time, get rid of your symptoms.
As an antibiotic, doxycycline is only effective against infections caused by bacteria and certain types of parasites. It does not treat the common cold, flu or viral infections.
Doxycycline is a versatile antibiotic medicine that’s used to treat several common and far less common bacterial infections. It’s also used as a prophylactic (preventative medicine) for some infectious diseases, such as malaria.
If you’re prescribed doxycycline, your healthcare may recommend using it by itself or with one or several other medications.
Doxycycline is often used as an acne treatment. As an antibiotic, it works by killing certain types of bacteria that can multiply inside clogged pores and cause acne breakouts to become infected and painful.
Acne develops when your hair follicles, or pores, become clogged with a combination of sebum (a type of natural oil produced by your sebaceous glands) and dead skin cells, which are left on the surface of your skin as a byproduct of epidermal turnover.
Acne becomes more severe when some types of bacteria, such as Propionibacterium acnes (P. acnes) multiply inside clogged hair follicles. As bacteria multiply, inflamed acne lesions such as pustules, nodules and cystic acne can develop.
Because of its effects on gram-positive bacteria, doxycycline is commonly used to stop bacteria from growing inside clogged pores and causing inflammatory acne breakouts.
In fact, doxycycline is one of the most common and preferred antibiotics prescribed as a systemic treatment for acne.
Your healthcare provider might prescribe doxycycline if you have moderate or severe acne, or if other antibiotics (such as topical clindamycin or azithromycin) haven’t fully stopped your acne breakouts.
Although doxycycline can kill acne-causing bacteria, it doesn’t have any significant effect on the sebum and dead skin cells that cause acne to develop in the first place.
Because of this, if you’re prescribed doxycycline for acne, your healthcare provider will generally also prescribe other medications for combination therapy. These may include:
Topical retinoids, such as tretinoin. These medications work by increasing the pace at which your skin produces new skin cells. Tretinoin, which is an active ingredient in our Prescription Acne Cream, peels away dead skin cells and unclogs blocked pores.
Benzoyl peroxide. This is an over-the-counter medication that works by preventing the bacteria that cause inflammatory acne from growing on your skin. It’s a common active ingredient in facial cleansers and other acne treatments.
Your healthcare provider may recommend using other over-the-counter acne treatments and/or skin care products with doxycycline.
In addition to treating acne, doxycycline is also used to treat a wide range of bacterial infections and medical conditions that can affect your skin.
Doxycycline is commonly used to treat rosacea, a common skin disease that can cause skin to blush or flush more easily. When rosacea is severe, it can involve redness and breakouts that look similar to inflamed acne.
As a treatment for rosacea breakouts, doxycycline is often prescribed at a low dose that stops it from acting like an antibiotic. Research shows that using doxycycline at a low dose can prevent acne-like breakouts from rosacea or lower their severity.
As a versatile antibiotic, doxycycline is widely prescribed as a treatment for bacterial sexually transmitted infections, or STIs. These include syphilis, chlamydia and gonorrhea, all of which are caused by different types of gram-negative bacteria.
Doxycycline may also be prescribed to prevent infection in people subject to sexual assault or rape.
In addition to sexually transmitted infections, doxycycline is used to treat infections that affect the genitals that aren’t sexually transmitted diseases, such as pelvic inflammatory disease or urinary tract infections (UTIs).
Because of its effectiveness against gram-positive and -negative bacteria, doxycycline is also a common treatment for other bacterial infections.
These include infections of the intestines, lymph system and urinary system, as well as common infections spread by infected animals, lice, mites, ticks and other parasites. Doxycycline is also commonly used to treat infections caused by contaminated food and/or drinking water.
Doxycycline is a widely-used treatment option for pneumonia and other respiratory infections. In certain cases, such as in people unable to be treated with penicillin antibiotics, doxycycline may be used to treat some types of food poisoning.
Doxycycline is often prescribed to prevent malaria. Your healthcare provider may prescribe this medication if you’re planning to travel to a malaria-endemic area.
If you’re prescribed doxycycline to prevent malaria, you should start to take your medication one to two days before traveling to any malaria-endemic areas, then continue using it for four weeks after returning to a malaria-free area.
Your healthcare provider will likely prescribe additional medication to use with doxycycline to prevent malaria.
For most people, doxycycline is a safe, effective antibiotic when it’s used as prescribed. As with all medications, there are several things that you should know before using doxycycline to treat acne, other bacterial infections or as a prophylaxis for malaria.
Doxycycline comes as a capsule, tablet or liquid. Your healthcare provider may instruct you to use doxycycline one or more times per day. Doxycycline typically works best when it’s taken on an empty stomach at least one hour before or two hours after eating.
The typical dosage of doxycycline for mild to moderate bacterial infections is 200mg on the first day, taken in two doses of 100mg 12 hours apart, then 100mg taken one time per day. Do not adjust your dosage of doxycycline without first consulting your healthcare provider.
It’s best to take doxycycline with an eight-ounce glass of water. Avoid taking doxycycline within three hours of any medications or dietary supplements that contain zinc, iron, aluminum, sodium bicarbonate (baking soda), calcium or magnesium, as these may affect absorption.
If you feel nauseous after using doxycycline, talk to your healthcare provider. Taking doxycycline with milk or food can help to reduce nausea, but it may affect absorption.
If you miss a dose of doxycycline, take the missed dose as soon as you can. If it’s almost time for your next dose of doxycycline, skip the missed dose and continue to use your medication as normal. Follow safe disposal instructions to throw away any unused medicine.
If you’re prescribed doxycycline to treat a bacterial infection, make sure to continue to use your medication even after the symptoms of your infection disappear. Stopping treatment early can potentially lead to a recurrent bacterial infection.
Do not use doxycycline for longer than the recommended treatment period or if your healthcare provider says it isn’t necessary. Using doxycycline or other antibiotics when they aren’t needed may increase your risk of developing an antibiotic-resistant infection in the future.
Doxycycline can potentially cause side effects, although serious side effects are rare. Common side effects of doxycycline include:
Discoloration of teeth
Other potential adverse effects of doxycycline include loss of appetite, swollen tongue, anxiety, dry mouth, itching that affects your vagina and/or rectum, a sore and/or irritated mouth, skin or nail color changes and back pain.
It’s important to talk to your healthcare provider if any side effects of doxycycline are persistent or bothersome.
In some cases, doxycycline may cause serious adverse events or signs of an allergic reaction. These may include:
Double vision, blurry vision or vision loss
Severe rash with swollen glands and/or fever
Peeling, blistering or red skin
Shortness of breath and difficult breathing
Severe stomach pain or chest pain
Irritation of the throat and difficulty swallowing
Fast or irregular heartbeat
Unusual bleeding and/or bruising
Dysuria (pain when urinating)
Persistent bloody or watery bowel movements
Exacerbation of systemic lupus erythematosus (SLE)
Intracranial hypertension (high pressure in the brain)
Recurrent symptoms of bacterial infection
Permanent tooth discoloration
Leukopenia (low white blood cell count)
It’s important to contact your healthcare provider if you experience any of these side effects or adverse drug reactions. Seek emergency medical help if you develop severe symptoms during treatment with doxycycline.
Doxycycline can make your skin more sensitive to sunlight, meaning you may burn easily while using it as a treatment for a bacterial infection or for malaria prophylaxis.
While you’re using doxycycline, make sure to wear protective clothing, use SPF 30+ sunscreen and limit your sun exposure. Wear sunglasses and try to spend time in the shade when you’re outdoors. Inform your healthcare provider if you get a sunburn while using this medication.
Do not use tanning beds or deliberately spend time tanning in the sun while using doxycycline.
Doxycycline can interact with certain medications, potentially causing side effects or reducing its effectiveness. Before taking doxycycline, it’s important to tell your healthcare provider if you use or have recently used any of the following medications:
Anticoagulants (blood thinners)
Barbiturates (medications used to treat anxiety and sleep disorders)
Oral retinoids, such as acitretin or isotretinoin
Bismuth subsalicylate (Pepto-Bismol®)
Other oral or topical antibiotics, including penicillin
Proton pump inhibitors
It’s also important to tell your healthcare provider about any health conditions that affect you or have previously affected you, including conditions for which you’re receiving treatment.
It’s especially important to tell your healthcare provider if you have a history of yeast infections, liver disease, colitis linked to antibiotic therapy, porphyria, kidney disease diarrhea caused by a C. difficile infection, myasthenia gravis or a history of lupus.
Doxycycline is generally safe when used as prescribed. However, it may not be safe to use in certain situations. Make sure to follow the safety warnings below to avoid side effects or harm while using doxycycline:
Doxycycline is not safe for use during pregnancy, may harm your fetus and can pass into breast milk. You should not use doxycycline if you’re pregnant, breastfeeding or planning to become pregnant in the near future.
Doxycycline should not be used in children except to treat Rocky Mountain spotted fever, anthrax and in other emergency situations. Doxycycline may cause permanent yellowing of the teeth when used in children under 12 years of age.
Doxycycline may reduce the effectiveness of hormonal birth control pills, including birth control pills used to treat acne. Other forms of hormonal birth control, such as the patch, ring or the birth control shot (Depo-Provera®) may also become less effective. Make sure to inform your healthcare provider if you use a form of hormonal birth control before using doxycycline. You may need to use non-hormonal birth control while you’re prescribed doxycycline.
Doxycycline is a tetracycline antibiotic. Make sure to tell your health care provider if you have an allergy to tetracycline antibiotics or other types of medication.
If you have inflamed, inflammatory acne, doxycycline can help to stop bacterial growth and clear up your skin. It’s also a versatile drug that’s used for many other bacterial infections.
For acne, your healthcare provider may prescribe doxycycline with another type of medication to target your breakouts from multiple angles. Our selection of skin care products includes several prescription and over-the-counter treatments that may complement doxycycline.
Worried about your acne? Our guide to getting rid of acne goes into more detail about your best options for controlling and preventing breakouts, from antibiotics to retinoids, birth control, good skin care habits and more.