This medication is used to treat a wide variety of bacterial infections, including those that cause acne. This medication is also used to prevent malaria. This medication is known as a tetracycline antibiotic. It works by stopping the growth of bacteria.

This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Using any antibiotic when it is not needed can cause it to not work for future infections.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This drug may also be used for a certain skin condition (rosacea).

This medication is best taken by mouth on an empty stomach (at least 1 hour before or 2 hours after a meal) as directed by your doctor, usually 1 or 2 times daily. Take this medication with a full glass of water (8 ounces/240 milliliters) unless directed otherwise. If stomach upset occurs, taking it with food or milk may help. However, doxycycline may not work as well if you take it with food or milk (or anything high in calcium - more details below ), so ask your doctor or pharmacist if you may take it that way. Do not lie down for at least 10 minutes after taking this medication.

Take this medication 2 to 3 hours before or after taking any products containing aluminum, calcium, iron, magnesium, zinc, or bismuth subsalicylate. Some examples include antacids, quinapril, sucralfate, vitamins/minerals, dairy products (such as milk, yogurt), and calcium-enriched juice. These products bind with doxycycline, preventing your body from fully absorbing the drug.

When using to prevent malaria, take this medication as directed by your doctor, usually once daily, starting 1 to 2 days before travel. Continue to take this medication daily while in the malarious area. Upon returning home, you should keep taking this medication for 4 more weeks. If you are unable to finish this course of doxycycline, contact your doctor.

Do not crush or chew the medication. Swallow the capsules whole. If you have difficulty swallowing the capsule, the capsule may be opened and the contents sprinkled onto cool applesauce and taken immediately as directed. If you have difficulty swallowing the tablet, the tablet may be broken up carefully and the contents (pellets) sprinkled onto cool applesauce and taken immediately as directed. Make sure not to crush or damage the pellets when breaking up the tablet. Do not prepare a supply in advance. Do not chew the food/medication mixture because doing so may cause the drug to be released too quickly, increasing side effects. Drink a glass of cool water after each dose to ensure complete swallowing of the medication.

The dosage is based on your medical condition and response to treatment. Children's dosage may also be based on weight.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.

Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Tell your doctor if your condition lasts or gets worse.

Stomach upset, diarrhea, nausea, or vomiting may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• painful/difficult swallowing
• signs of kidney problems (such as change in the amount of urine)

Tetracycline drugs such as doxycycline may rarely cause increased pressure around the brain (intracranial hypertension-IH). The risk of this side effect is greater for women of childbearing age who are overweight or who have had IH in the past. If IH develops, it usually goes away after doxycycline is stopped; however, there is a chance of permanent vision loss or blindness. Get medical help right away if you have:

• headache that is severe or doesn't stop
• nausea/vomiting that doesn't stop
• vision changes (such as blurred/double vision, decreased vision, sudden blindness)

This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop:

• diarrhea that doesn't stop
• abdominal or stomach pain/cramping
• blood/mucus in your stool

If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• fever that doesn't go away
• new or worsening lymph node swelling
• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

See also Side Effects section.

Before taking doxycycline, tell your doctor or pharmacist if you are allergic to it; or to other tetracyclines (such as minocycline); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• trouble swallowing
• esophagus problems (such as hiatal hernia or reflux/heartburn)

Doxycycline may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using doxycycline before having any immunizations/vaccinations.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.

Children younger than 8 years may be more sensitive to the side effects of doxycycline, especially tooth discoloration. Tooth discoloration has also occurred in older children and young adults. Discuss the risks and benefits of this medication with the doctor.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using doxycycline. Doxycycline may harm an unborn baby. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.

This medication passes into breast milk. Consult your doctor before breastfeeding.

See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include:

• retinoid medications taken by mouth (such as acitretin, isotretinoin)
• barbiturates (such as phenobarbital)
• "blood thinners" (such as warfarin)
• digoxin
• anti-seizure medications (such as phenytoin)
• strontium

This medication may interfere with certain lab tests (such as urine catecholamine levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

If this medication is being used to prevent malaria, it is important to understand that it is still possible to get the disease even if you have used this medication. Avoid being bitten by mosquitoes when trying to prevent malaria. Avoid contact with mosquitoes, especially from dusk to dawn, by staying in well-screened areas, wearing protective clothing, and using insect repellent and bed nets.

This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to.

Lab and/or medical tests (such as complete blood count, liver/kidney function) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Different brands of this medication have different storage needs. Check the product package for instructions on how to store your brand, or ask your pharmacist. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Taking outdated tetracycline-related drugs can result in serious illness. Consult your pharmacist or local waste disposal company.