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.
Read the Patient Information Leaflet if available from your pharmacist before you start taking doxycycline and each time you get a refill. If you have any questions, ask your doctor or pharmacist. This medication is best taken by mouth on an empty stomach, at least 1 hour before or 2 hours after a meal, usually 1 or 2 times daily or as directed by your doctor. 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, didanosine solution, quinapril, 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, this medication is usually taken once daily. Take the first dose of this medication 1 to 2 days before travel or as directed by your doctor. 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. If you are using the liquid form of this medication, shake the bottle well before each dose. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. The dosage is based on your medical condition and response to treatment. For children, the 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 allow bacteria to continue to grow, which may result in a return of the infection. Tell your doctor if your condition persists or worsens.
Stomach upset, diarrhea, nausea, or vomiting may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she 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 a serious increase in pressure inside the skull (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: persistent/severe headache, vision changes (such as blurred/double vision, decreased vision, sudden blindness), persistent nausea/vomiting. This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea or opioid medications if you have any of the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool. 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.
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.
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. Although most antibiotics (including doxycycline) are unlikely to affect hormonal birth control such as pills, patch, or ring, a few antibiotics (such as rifampin, rifabutin) can decrease their effectiveness. This could result in pregnancy. If you use hormonal birth control, ask your doctor or pharmacist for more details. This medication may interfere with certain laboratory tests (including urine catecholamine levels), possibly causing false test results. Make sure laboratory 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 their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.