Description: Doxycycline is a tetracyclic antibiotic that blocks bacterial protein synthesis due to disruption of transfer RNA and messenger RNA at ribosomal sites.
Absorption: Readily absorbed from the GIT (oral).
Distribution: Widely distributed; crosses the blood-brain barrier; enters breast milk. Protein-binding: Extensive.
Metabolism: Extensively hepatic via demethylation to desmethyldoxepin, hydroxylation, N-oxidation.
Excretion: Urine (as metabolites); 8-24 hrs (elimination half-life).


This medication is used to treat a wide variety of bacterial infections, including those that cause acne. This medication is also used to prevent malaria.

OTHER USES:   This drug may also be used to treat a certain skin condition (rosacea).

How to use doxycycline:


Adults- 200 mg on the first day of treatment, followed by a maintenance of 100 mg daily.

Pediatrics- 4.4 mg/kg of body weight in two divided doses on the first day, followed by a maintenance of 2.2 mg/kg given as a single dose or two divided doses.

  • This medication is best taken by mouth on an empty stomach, at least 1 hour before or 2 hours after a meal, usually 1 or 2 times daily or as directed by your doctor.
  • Take this medication with a full glass of water (8 ounces/240 milliliters) unless directed otherwise.
  • If stomach upset occurs, taking it with food or milk may help.
  • However, doxycycline may not work as well if you take it with food or milk (or anything high in calcium – more details below ), so ask your doctor or pharmacist if you may take it that way.
  • Do not lie down for 10 minutes after taking this medication.
  • 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, didanosine solution, quinapril, vitamins/minerals, dairy products (such as milk, yogurt), and calcium-enriched juice.
  • When using to prevent malaria, this medication is usually taken once daily. Take the first dose of this medication 1 to 2 days before travel or as directed by your doctor. Continue to take this medication daily while in the malarious area. Upon returning home, you should keep taking this medication for 4 more weeks. If you are unable to finish this course of doxycycline, contact your doctor.

Tooth development: The use of drugs of the tetracycline class during tooth development (last half of pregnancy, infancy and childhood to the age of 8 years) may cause permanent discoloration of the teeth (yellow-graybrown).

Clostridium difficile-associated diarrhea: If CDAD is suspected or confirmed, ongoing antibacterial use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

Photosensitivity: Photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines.

Intracranial hypertension: Tetracycline drugs such as doxycycline may rarely cause a serious increase in pressure inside the skull (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 doxycycline is stopped; however, there is a chance of permanent vision loss or blindness.

Common side effects:

  • stomach upset,
  • diarrhea,
  • nausea, or
  • vomiting

Tell your doctor right away if you have any serious side effects, including:

  • sunburn (sun sensitivity),
  • painful/difficult swallowing,
  • change in the amount of urine.

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, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.


  • Allergy: Before taking doxycycline, tell your doctor or pharmacist if you are allergic to it; or to other tetracyclines (such as minocycline); or if you have any other allergies.
  • Medical History: Before using this medication, tell your doctor or pharmacist if you had: trouble swallowing, esophagus problems (such as hiatal hernia or reflux/heartburn).
  • This medication may make you more sensitive to the sun. Avoid prolonged sun exposure, tanning booths, and sunlamps. Use a sunscreen and wear protective clothing when outdoors.

Pregnancy Risk:  Category D.  This medication is not recommended for use during pregnancy. It may harm an unborn baby. Consult your doctor for more details.

Breastfeeding: This drug passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.


  • Some products that may interact with this drug include: retinoid medications taken by mouth (such as acitretin, isotretinoin), barbiturates (such as phenobarbital), “blood thinners” (such as warfarin), digoxin, penicillins, anti-seizure medications (such as carbamazepine, phenytoin), strontium, live bacterial vaccines.
  • Although most antibiotics (including doxycycline) are unlikely to affect hormonal birth control such as pills, patch, or ring, a few antibiotics (such as rifampin, rifabutin) can decrease their effectiveness. This could result in pregnancy. If you use hormonal birth control, ask your doctor or pharmacist for more details.


If overdose is suspected, contact a poison control center or emergency room immediately.


Do not share this medication with others.

If this medication is being used to prevent malaria, it is important to understand that it is still possible to get the disease even if you have used this medication. Avoid being bitten by mosquitoes when trying to prevent malaria. Avoid contact with mosquitoes, especially from dusk to dawn, by staying in well-screened areas, wearing protective clothing, and using insect repellent and bed nets.

This medication has been prescribed for your current condition only. Do not use it later for another infection unless told to do so by your doctor. A different medication may be necessary in that case.

Laboratory and/or medical tests (such as complete blood count, liver/kidney function) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

Missed Dose

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 and resume your usual dosing schedule. Do not double the dose to catch up.


Store at room temperature away from light and moisture. Different brands of this medication have different storage needs. Check the product package for instructions on how to store your brand, or ask your pharmacist. Do not store in the bathroom. Keep all medicines 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 tetracycline-related drugs can result in serious illness. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.


Available brands

  • Bactidox [ Unison ]
  • Doxicon [ Vendiz ]
  • Dyna-Doxycycline [ Crisdy-Na ]
  • Medox [ Lloyd ]
  • RiteMED Doxycycline [ RiteMED ]
  • Tedoxy [ Korea United Pharma ]
  • Teradox [ Hovid ]
  • Vibramycin [ Pfizer ]

Also marketed as

  • Aldoxy [ Lloyd ]
  • Comxin [ Scheele ]
  • Cytragen [ Vonnace ]
  • Doryx [ Faulding ]
  • Doximax [ Maxtar Bio-genics ]
  • Doxin [ BioFemme ]
  • Doxylyn [ Westfield ]
  • Harvellin [ Zeutica ]
  • QB International Doxycycline [ Unibios Lab ]
  • Quedox [ Ajanta Pharma Phil ]

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