doxycycline

Doxycycline is a synthetic (man-made) antibiotic derived from tetracycline.

Doxycycline works by interrupting the production of proteins by bacteria. It is effective against a wide variety of bacteria, such as Hemophilus influenzae, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, Neisseria gonorrhoea, and many others.

Doxycycline is used for many different types of infections, including respiratory tract infections due to Hemophilus influenzae, Streptococcus pneumoniae, or Mycoplasma pneumoniae. It also is used for the treatment of

• non-gonococcalurethritis (due to Ureaplasma),
• Rocky Mountain spotted fever,
• typhus,
• chancroid,
• cholera,
• brucellosis,
• anthrax,
• syphilis,
• acne, and,
• periodontal disease.

Doxycycline is generally well-tolerated. The most common side effects are

• diarrhea or loose stools,
• nausea,
• abdominal pain, and
• vomiting.

Tetracyclines, such as doxycycline, may cause tooth discoloration if used in persons below 8 years of age. Exaggerated sunburn can occur with tetracyclines; therefore, sunlight should be minimized during treatment.

• The absorption of doxycycline is not markedly affected by food, and therefore, it can be taken with meals.
• For most infections, doxycycline is taken once or twice daily for 7 to 14 days.
• For adult infections, the usual dose of oral doxycycline is 200 mg on the first day of treatment (100 mg every 12 hours) followed by a dose of 100 to 200 mg/day as a single dose or divided and administered twice daily.

• It is recommended that doxycycline not be taken at the same time as aluminum, magnesium, or calcium based antacids, such as Mylanta, Maalox, Tums, or Rolaids because, like food, these medications bind doxycycline in the intestine and prevent its absorption. Similarly, doxycycline should not be taken with minerals (such as calcium or iron) or with bismuth subsalicylate (Pepto Bismol).
• Doxycycline may enhance the activity of warfarin (Jantoven) and cause excessive "thinning" of the blood leading to exaggerated bleeding, necessitating a reduction in the dose of warfarin. Phenytoin (Dilantin), carbamazepine (Tegretol), and barbiturates (such as phenobarbital) may enhance the metabolism (destruction) of doxycycline thus making it less effective.
• Doxycycline may interfere with the action of penicillins and should not be combined with penicillins. It may also reduce the effect of oral contraceptives. Combining tetracycline and methoxyflurane (Penthrane) may reduce kidney function.

• Tetracycline antibiotics, such as doxycycline, can have toxic effects on development of bone in the fetus. Therefore, tetracyclines are not recommended during pregnancy unless there is no other appropriate antibiotic.
• Doxycycline is secreted into breast milk but the extent of absorption by the breastfed infant is not known. Since tetracyclines can cause toxic effects on bone, the use of tetracyclines in nursing mothers is of concern. The physician must decide whether to recommend that a nursing mother discontinue nursing during treatment with tetracyclines or change to a different antibiotic.

Do I need a prescription for doxycycline?

Yes

What preparations of doxycycline are available?

• Capsules: 50, 75, 100 and 150 mg.
• Capsule (Delayed Release): 40 mg.
• Tablets: 20, 50, 75, 100 and 150 mg.
• Tablets (Delayed Release): 50, 60, 75, 80, 100, 120, 150, and 200 mg.
• Syrup: 50 mg/5 ml (teaspoon)
• Oral Suspension: 25 mg/5ml
• Powder for injection: 100and 200 mg.
• Periodontal Extended Release Liquid: 10%

How should I keep doxycycline stored?

• Tablets, capsules, and syrup should be kept at room temperature 15 C to 30 C (59 F to 86 F) in tight, light resistant containers.
• Powder for injection should be stored at or below 25 C (77 F) and protected from light.
• Atridox (doxycycline in a gel used for subgingival application) should be stored at 2 C to 8 C (36 F to 46 F).

When was doxycycline approved by the FDA?

The FDA approved doxycycline in December 1967.