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Generic name: demeclocycline [ DEM-e-kloe-SYE-kleen ]
Brand name: Declomycin
Dosage form: oral tablet (150 mg; 300 mg)
Drug class: Tetracyclines

Medically reviewed by on May 23, 2023. Written by Cerner Multum.

What is demeclocycline?

Demeclocycline is a tetracycline antibiotic that is used to treat many different bacterial infections, such as urinary tract infections, lung infections, intestinal infections, acne, gonorrhea, chlamydia, Rocky Mountain spotted fever, and others.

Demeclocycline may also be used for purposes not listed in this medication guide.

Demeclocycline side effects

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).

Demeclocycline may cause serious side effects. Call your doctor at once if you have:

  • severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);

  • new or worsening cough, fever, trouble breathing;

  • painful swallowing, vomiting blood (avoid lying down right after taking demeclocycline);

  • kidney problems--swelling, urinating less, feeling tired or short of breath;

  • low blood cell counts--fever, chills, tiredness, confusion or weakness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;

  • increased pressure inside the skull--severe headaches, ringing in your ears, dizziness, nausea, vision problems, pain behind your eyes; or

  • signs of liver or pancreas problems--loss of appetite, upper stomach pain (that may spread to your back), tiredness, nausea or vomiting, fast heart rate, dark urine, jaundice (yellowing of the skin or eyes).

Common side effects of demeclocycline may include:

  • nausea, vomiting, diarrhea, loss of appetite;

  • darkened skin color;

  • swollen tongue, trouble swallowing; or

  • vaginal itching or discharge.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Using demeclocycline during pregnancy may cause bone growth problems in the unborn baby, or permanent tooth discoloration later in life.

Children younger than 8 years old should use demeclocycline only for infections that cannot be treated with a safer antibiotic.

Before taking this medicine

You should not use demeclocycline if you are allergic to demeclocycline or similar antibiotics such as doxycycline, minocycline, or tetracycline.

Tell your doctor if you have ever had:

  • liver or kidney disease;

  • diabetes; or

  • lupus.

If you are using demeclocycline to treat gonorrhea, your doctor may test you to make sure you do not also have syphilis, another sexually transmitted disease.

Do not use if you are pregnant. Taking demeclocycline during the second or third trimester of pregnancy may cause bone growth problems in the unborn baby, or permanent tooth discoloration later in life.

Demeclocycline can make birth control pills less effective. Ask your doctor about other birth control options such as an injection, implant, skin patch, vaginal ring, condom, diaphragm, cervical cap, or contraceptive sponge.

Demeclocycline can pass into breast milk and may affect bone and tooth development in a nursing infant. Do not breastfeed while you are taking doxycycline.

Children younger than 8 years old should use demeclocycline only for infections that cannot be treated with a safer antibiotic. Demeclocycline can affect a child's growth or cause permanent yellowing or graying of the teeth.

How should I take demeclocycline?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take on an empty stomach, at least 1 hour before or 2 hours after a meal.

Keep using this medicine even if your symptoms quickly improve. Skipping doses could make your infection resistant to medication. Demeclocycline will not treat a viral infection (flu or a common cold).

Demeclocycline is usually given for up to 2 days after symptoms and fever have cleared.

Do not share this medicine with another person, even if they have the same symptoms you have.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

Throw away any unused medicine after the expiration date on the label has passed.

Demeclocycline dosing information

Usual Adult Dose for SIADH:

(Not approved by FDA)

Initial dose: 600 to 1200 mg/day orally in 3 or 4 divided doses
Maintenance dose: 600 to 900 mg/day orally or the lowest effective dosage to prevent hyponatremia

Usual Adult Dose for Bacterial Infection:

150 mg orally 4 times a day or 300 mg orally twice a day

Usual Pediatric Dose for Bacterial Infection:

Above 8 years of age: 7 to 13 mg/kg/day orally divided in 2 to 4 doses
Maximum dose: 600 mg/day

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking demeclocycline?

Avoid taking anti-diarrhea medicine without first asking your doctor. Diarrhea may be a sign of a new infection.

Demeclocycline could make you sunburn more easily. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Avoid taking iron supplements, multivitamins, calcium supplements, antacids, or laxatives.

Do not take with milk or other dairy products unless your doctor tells you to.

What other drugs will affect demeclocycline?

Tell your doctor about all your other medicines, especially a blood thinner such as warfarin, Coumadin, or Jantoven.

Other drugs may affect demeclocycline, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.