Demeclocycline is used to treat a wide variety of bacterial infections, including those that cause acne. 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 hormone imbalance (Syndrome of Inappropriate Antidiuretic Hormone-SIADH) which causes your body to retain water and your urine to be more concentrated than it should be.

Take this medication by mouth on an empty stomach (at least 1 hour before or 2 hours after a meal) as directed by your doctor, usually 2 to 4 times a day. Take each dose with a full glass of water (8 ounces or 240 milliliters) unless your doctor directs you otherwise. Do not lie down for at least 10 minutes after taking this drug. For this reason, do not take it right before bedtime.

If stomach upset occurs, ask your doctor if you can take this medication with food.

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 demeclocycline, preventing your body from fully absorbing the drug.

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.

If you are taking this medication to treat an infection, continue to take it 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. If you are using this medication to treat SIADH, you should notice an increase in the amount of urine within 5 days.

Diarrhea, loss of appetite, nausea, vomiting, headache, dizziness, lightheadedness, or rectal discomfort 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:

• darkening of the skin and other areas of the body (such as lips, inside of the mouth)
• difficult/painful swallowing
• unusual increase in the amount of urine (except for the expected increase in urination if you are treating SIADH)
• unusual decrease in the amount of urine or no urine
• unusual thirst
• weakness
• unusual tiredness
• brown/gray tooth discoloration
• hearing changes (such as ringing in the ears, decreased hearing)
• easy bruising/bleeding
• new signs of infection (such as sore throat that doesn't go away, fever, chills)
• signs of liver disease (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine)

Tetracycline drugs such as demeclocycline 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 demeclocycline is stopped; however, there is a chance of permanent vision loss or blindness. Get medical help right away if you have:

• nausea/vomiting that doesn't stop
• headache that is severe or doesn't go away
• 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:

• rash
• skin sores/blisters
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing
• new or worsening swelling/pain in the joints
• chest pain
• fast/irregular heartbeat

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 demeclocycline, tell your doctor or pharmacist if you are allergic to it; or to other tetracycline medication (such as doxycycline, minocycline, tetracycline); 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:

• kidney disease
• liver disease
• problems swallowing
• esophagus problems (such as esophageal ulcers, hiatal hernia, acid reflux disease-GERD)
• lupus
• a certain hormone imbalance called "water diabetes" (diabetes insipidus)

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

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

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. Get medical help right away if you get sunburned or have skin blisters/redness.

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

This medication should not be used by children younger than 8 years of age because it may cause permanent tooth discoloration and other problems. Tooth discoloration has also occurred in older children and young adults. Consult your doctor for more information.

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using demeclocycline. Demeclocycline 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 are:

• retinoid medications taken by mouth (such as acitretin, isotretinoin)
• strontium

This medication may interfere with certain lab tests (such as some urine tests for sugar), 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.

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

With long-term use or if this medication is used to treat SIADH, lab and/or medical tests (such as complete blood count, kidney/liver function, mineral levels) should 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. 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 demeclocycline can result in serious illness. Consult your pharmacist or local waste disposal company.