Doxycycline: Important Information You Need To Know


  • Doxycycline is a synthetic tetracycline antibiotic.
  • Doxycycline is available in Capsule, tablets, Oral Suspension, Syrup And Powder For Injection.
  • It is Used To treat a wide variety of bacterial infections including those that cause acne.
  • Brand Names For Doxycycline Includes Vibramycin, Adoxa, Atridox etc

Mechanism Of Action:

Doxycycline is lipophilic and can pass through the lipid bilayer of bacteria. Doxycycline reversibly binds to the 30 S ribosomal subunits and possibly the 50S ribosomal subunit(s), blocking the binding of aminoacyl tRNA to the mRNA and inhibiting bacterial protein synthesis.It works by interrupting the production of proteins by bacteria. Doxycycline prevents the normal function of the apicoplast of Plasmodium falciparum, malaria causing organism.

Uses And Dosage

Doxycycline is used to treat a variety of bacterial infections and  certain other microorganisms, including the following:

1. Infection of the sinuses.

Dose:100 mg orally twice a day or 200 mg orally once a day

2. Infections of the lungs and airways (chest or lower respiratory tract infections), such as pneumonia or flare-ups of chronic bronchitis.

Dose: In Pneumonia the Initial dose should be 200 mg IV on the first day, given in 1 or 2 infusions and then Maintenance dose: 100 to 200 mg/day IV.

3. Sexually-transmitted infections such as gonorrhea, chlamydia, syphilis, chancroid, lymphogranuloma venereum and granuloma inguinale.

Dose: The dose of 100mg twice a day for 7-10 days.In case of Syphilis a dose of  300mg a day in divided doses for 10 days.

4. Urinary tract infections and nongonococcal urethritis

Dose: 100 to 200 mg/day IV or 100 mg per day orally in a single dose or 50mg two times a day.

5. Prevent traveller’s diarrhea

Dose:200mg on the first day of travel followed by 100mg a day throughout the duration of the stay.

6. Pelvic inflammatory disease.

Dose: 100 mg orally or IV every 12 hours for 14 days

7. Louse and tick-borne relapsing fever, eg Lyme disease

Dose: A single dose of 100-200mg depending upon the severity of the infection.

8. Rare infection caused by Brucella bacteria (brucellosis).

Dose: 100 to 200 mg/day IV.

9. Rare bacterial infection of rodents and rabbits that can be transmitted to humans (tularemia).

Dose: 100 to 200 mg/day IV or 100 mg orally once a day OR 50 mg orally every 12 hours

10. Cholera.

Dose: 100 to 200 mg/day IV And 100 mg orally once a day OR 50 mg orally every 12 hours

11. Disease caused by infection with Leptospira bacteria (Weil’s Disease/leptospirosis).

Dose: A dose of 200mg once a week throughout the stay in the infected area and 200mg at the end of the trip.

12. Treatment of malaria caused by chloroquine-resistant Plasmodium falciparum.

Dose:200mg a day for at least 7 days, should be given with other drugs such as quinine.

13. Acne rosacea.

Dose: 40 mg orally once a day in the morning

14. Acne vulgaris.

Dose: 50mg a day with food or fluid for 6-12 weeks.


Side Effects:

More common, but less serious, side effects include:

  • Vaginal yeast infection
  • Nausea, vomiting, diarrhea
  • Increased sensitivity of the skin to sunlight

Some possible uncommon but serious side effects of doxycycline include:

  • Irritation of the esophagus
  • Blood problems (symptoms are unusual bleeding or bruising)
  • A life-threatening allergic reaction (symptoms are trouble breathing; closing of the throat; swelling of the lips, tongue, or face; hives)
  • Liver damage (symptoms are yellowing of the skin or eyes, dark urine, nausea , vomiting, loss of appetite, abdominal pain)

Pregnancy And Doxycycline:

Doxycycline is secreted into breast milk and can have toxic effects on the development of bone in the fetus. Therefore, it is not recommended during pregnancy unless there is no other appropriate antibiotic.

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