Tetracycline analogues such as Doxycycline have been shown to be effective in treating meibomian gland dysfunction. The beneficial effect on blepharitis is via 2 mechanisms: 1) reduction in the bacterial load on the eyelid, and 2) Antiinflammatory action. Doxycycline inhibits the production of free fatty acid (degradation product of meibomian gland lipid). Free fatty acid (FFA) can destabilize the tear film (causing dry eye) and can promote inflammation. By reducing the formation of FFA, eyelid inflammation is reduced and the tear film also becomes more stable.

The treatment duration is typically for several months. The preferred dose of Doxycycline is 100 mg once a day for at least 3 months. Several very important points need to be considered prior to initiating doxycycline treatment.

• Doxycycline and other members of the tetracycline class of antibiotics are not generally approved for treating patients under 8 years old. These antibiotics can cause swelling of the brain and a condition called bulging fontanels (soft spot on head) in infants.

• Tetracycline antibiotics are associated with permanent tooth discoloration in children. If used for long periods, they may also slow down the growth of teeth and bones in babies born prematurely.

• Before taking any tetracycline antibiotic, review with your health care provider ALL medicines you are taking, including those you take without a prescription. Tetracycline antibiotics can affect how other medicines work and other medicines can affect how the antibiotic works.

• Some medicines that can interact with doxycycline are antacids and supplements that contain calcium, iron, magnesium, or sodium bicarbonate. If you take products containing these minerals within 2 hours of the time you take doxycycline, these medicines could decrease the doxycycline’s effectiveness.

• Birth control pills also may not work as well if you are taking doxycycline. Use other forms of birth control while you are taking this medicine.

• The use of doxycycline during pregnancy has historically been discouraged. This is due to the knowledge that tetracyclines cause cosmetic staining of the primary dentition in fetuses exposed during the second or third trimester of pregnancy and concerns about possible enamel hypoplasia and depression of fetal bone growth.

• Doxycycline is excreted into breast milk, therefore the use of doxycycline during lactation is discouraged.