What is doxycycline used for?

Doxycycline is an antibiotic that is commonly used to prevent malaria, improve tooth attachment and reduce gum pockets in people who have a dental procedure called scaling and root planing for gum disease (periodontitis), and treat the following infections caused by certain bacteria. 

  • Infections from tick bites, including Rickettsial diseases
  • Certain sexually transmitted infections (STIs)
  • Respiratory tract infections, such as bronchitis, pneumonia, or sinusitis 
  • Certain eye infections (e.g,. trachoma, inclusion conjunctivitis)
  • Severe acne
  • An infection called plague 
  • An infection called cholera
  • An infection called anthrax
  • Certain infections spread from animals
  • Certain infections when penicillin cannot be used
  • Specific infections caused by parasites

Doxycycline may not be appropriate for some of the infections listed above, depending on which germs are causing the infection. Bacteria in some locations may have developed resistance to doxycycline, which will make it less effective.

Doxycycline may also be used for other conditions as determined by your healthcare provider.

How does doxycycline work (mechanism of action)?

Doxycycline kills certain types of bacteria by blocking their ability to create proteins. Doxycycline also works against the parasite that causes malaria, but the exact mechanism of action is not known. Doxycycline may help to prevent the breakdown of gum tissue.

How is doxycycline supplied (dosage forms)?

Doxycycline is available as Acticlate, Doryx, Doryx MPC, Monodox, Vibramycin, and generic doxycycline in the following dosage forms that are taken by mouth.

  • 50 mg, 75 mg, 100 mg, and 150 mg oral capsules
  • 50 mg, 60 mg, 80 mg, and 200 mg oral delayed-release tablets
  • 20 mg, 50 mg, 75 mg, 100 mg, and 150 mg oral tablets
  • 25 mg/5 mL oral suspension
  • 50 mg/5 mL oral suspension

Doxycycline is also available in injectable forms.

How should I store doxycycline?

Doxycycline should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C), for shorter periods of time, such as when transporting it. Keep tightly closed. Protect from light.

Side Effects

What are the most common side effects of doxycycline?

The most common side effects of doxycycline are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Loss of appetite
  • Nausea
  • Vomiting
  • Diarrhea (see below)
  • Rash or hives
  • Sensitivity to sunlight (see below)

There may be other side effects of doxycycline that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at or by calling 866-234-2345.

What are the serious side effects of doxycycline?

While less common, the most serious side effects of doxycycline are described below, along with what to do if they happen.

Antibiotic-associated Diarrhea. An overgrowth of germs called Clostridioides difficile, or “C. diff,” can happen in your gut with many types of antibiotics, including doxycycline. This can cause a condition known as antibiotic-associated diarrhea and can happen even up to 2 months after stopping the antibiotic. Call your healthcare provider right away if you have any of the following symptoms of this condition.

  • Watery diarrhea
  • Diarrhea that does not go away
  • Blood in your stool (poop)
  • Severe stomach cramps
  • Fever that starts after you start or finish the medicine

Severe Allergic Reactions. Doxycycline can cause allergic reactions, including DRESS which can be serious. DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms. It is also sometimes called multi-organ hypersensitivity. This is a reaction that can affect multiple parts of the body including your liver, kidneys, and heart. Stop taking the medicine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes 
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain
  • Swelling in your feet, ankles, or legs
  • Dark colored urine
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Severe Skin Reactions. Doxycycline can cause severe skin reactions called Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), exfoliative dermatitis, and erythema multiforme that can lead to death if not treated. If you develop a rash, stop doxycycline and call your healthcare provider right away. Get emergency help right away if you have any of the following symptoms.

  • Painful red or purple skin that looks burned and peels off
  • Flat or raised red, pink, or purple rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes

Sensitivity to Sunlight. Your skin may be very sensitive to light from the sun and devices that give off similar light, such as sunlamps and tanning beds, while you are taking certain drugs, including doxycycline. This is called photosensitivity. Use sunscreen and wear a hat and clothes that cover your skin if you need to be in the sunlight. Exposing your skin to this kind of light, even for a short time, can cause your skin to be severely sunburned, blistered, or swollen. Stop doxycycline and tell your healthcare provider right away if any of these happen.

Another Infection. Using doxycycline may lead to an infection with other types of germs, such as fungi. Call your healthcare provider if your infection does not improve or gets worse. 

Increased Pressure Around the Brain. Doxycycline can increase the pressure around the brain, a serious condition called pseudotumor cerebri or intracranial hypertension. Stop taking doxycycline and call your healthcare provider right away if you experience any of the following symptoms.

  • Dizziness
  • Nausea and vomiting
  • Severe headache
  • Vision changes

Permanent Teeth Discoloration. Doxycycline can cause a permanent change in tooth color to yellow, gray, or brown. It may also affect growth of tooth enamel (also called enamel hypoplasia). These side effects can happen during tooth development in the last half of pregnancy and in children up to age 8 years. Tell your healthcare provider if you are or plan to become pregnant. If your child is taking doxycycline and is less than 8 years old, call your healthcare provider right away.

Blood Disorders. Doxycycline can cause blood disorders such as hemolytic anemia, low platelet levels (thrombocytopenia), low neutrophil levels (neutropenia), and low eosinophil levels (eosinophilia). Stop using doxycycline and get help right away if you have any of the following symptoms of blood disorders.

  • Fever
  • Shortness of breath
  • Pale or yellowish skin
  • Easy bruising or bleeding
  • Frequent infection
  • Unusual weakness or tiredness
  • Dizziness, lightheadedness, or feeling like you are about to pass out
  • Headache
  • Fast or abnormal heartbeat

Warnings & Precautions

Who should not use doxycycline?

Allergies to Ingredients. People who are allergic to any of the following should not use doxycycline.

  • Doxycycline
  • Vibramycin/Vibra-Tabs
  • Doryx
  • Doryx MPC
  • Acticlate
  • Doxy 100
  • Monodox
  • Any other medicine known as a tetracycline
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific doxycycline products they stock.

What should I know about doxycycline before using it?

Do not take doxycycline unless it has been prescribed to you by a healthcare provider. Take it as prescribed. Taking doxycycline in a way other than it was prescribed may increase the chance that bacteria will develop resistance to doxycycline. This may make doxycycline or other antibiotics not work as well in the future. Only take doxycycline for an infection if your healthcare provider has prescribed it for this reason.

Do not share doxycycline with other people, even if they have the same condition as you. It may harm them.

Keep doxycycline out of the reach of children.

Although doxycycline can be used for malaria prevention, it does not guarantee protection from malaria. Try to avoid being bitten by mosquitos. Carefully follow the instructions from your healthcare provider. You may need to continue the medicine for a period of time once you leave an area where malaria is a problem.

Do not chew or crush doxycycline delayed-release tablets (Doryx, Doryx MPC). Doxycycline delayed-release tablets (Doryx) can be carefully broken and sprinkled over a cold spoonful of applesauce. The applesauce must be swallowed immediately without chewing. 

Do not break, open, crush, dissolve, or chew doxycycline capsules (Acticlate). 

Take doxycycline with plenty of fluid. Doxycycline can irritate your throat. Drinking enough fluid to completely swallow the medicine lowers this risk.

For doxycycline suspension, shake the bottle well before each use and use an accurate measuring device to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Ask your pharmacist to recommend an appropriate measuring device.

What should I tell my healthcare provider before using doxycycline?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are taking. This will help them determine if doxycycline is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Kidney or liver problems 
  • Diarrhea
  • Vision problems
  • History of surgery on your stomach
  • History of yeast or fungal infections in the mouth or vagina 

Pregnancy. Doxycycline may cause harm to an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. If you become pregnant, contact your healthcare provider right away.

Breastfeeding. Doxycycline passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take doxycycline while breastfeeding. 


Does doxycycline interact with foods or drinks?

Foods and drinks that are high in calcium may decrease the amount of doxycycline that your body absorbs. You should not eat or drink dairy products like milk and yogurt or calcium-fortified products at the same time or near the time that you take doxycycline. 

It is unknown if drinking alcohol will affect doxycycline.

Does doxycycline interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are taking.

In particular, make sure that you discuss if you are taking any of the following before taking doxycycline.

  • A blood thinner, which is a medicine used to treat or prevent blood clots
  • A penicillin antibiotic, which is a medicine used for certain bacterial infections
  • An antacid containing calcium, aluminum, or magnesium
  • Iron, which is a medicine used to treat/prevent low iron levels
  • Bismuth subsalicylate (Pepto-Bismol), which is a medicine used for upset stomach, heartburn, and nausea
  • A barbiturate such as phenobarbital, butalbital, or primidone, which is a medicine that may be used to treat insomnia, migraines, or seizures
  • Carbamazepine (Tegretol, Carbatrol, and others), which is a medicine used for seizures and nerve pain
  • Phenytoin (Dilantin, Phenytek, and others), which is a medicine to control seizures
  • A birth control pill
  • An oral retinoid (isotretinoin, acitretin), which is a medicine used to treat skin conditions, such as acne and psoriasis
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Overdose/Missed Dose

What should I do if I accidentally use too much doxycycline?

If you or someone else has used too much doxycycline, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of doxycycline?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses. 

It is important to complete your prescribed course of doxycycline, even if your symptoms get better or go away. This will reduce the risk that future infections are not resistant to doxycycline or other similar medicines.

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