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What is doxycycline?

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The bottom line

Doxycycline is a common broad-spectrum antibiotic prescribed for many kinds of infections. Therapeutic doses of doxycycline are generally safe, but doxycycline may cause severe reactions. It is important to understand what doxycycline is, be aware of precautions, and know what to do in instances of unintentional ingestion, overdose, or misuse.

Prevention Tips

  • Take prescription medications exactly as prescribed.

  • Prior to taking any medication, read the directions on the label and ensure the correct quantity is being taken at the correct time.

  • Utilize child-resistant safety caps on medications.

  • Keep medications either locked up or in a hard to reach location.

  • Talk to your doctor or pharmacist about potential drug interactions if you are prescribed doxycycline

This Really Happened

An adult with a psychiatric disorder took 1 g doxycycline per day for 12 years. He developed blue-gray skin discoloration on his legs, liver damage, kidney damage, anemia, and heart block. These effects resolved when he stopped the medication, although it took more than a year to improve.

What is doxycycline?

Doxycycline is a tetracycline antibiotic available through a prescription and used to treat a broad spectrum of infections. Doxycycline formulations include hyclate, monohydrate, and calcium salts and can be administered orally as a tablet/capsule or intravenously. Tetracycline antibiotics interfere with bacterial function and growth by blocking protein synthesis, thereby killing infection-causing organisms.

What are the most common doxycycline brands?

Common brands of doxycycline include Vibramycin®, Doryx®, Doryx MPC®, Oracea®, Acticlate®, Atridox®, Doxy 100®, and Doxy 200®.

What is doxycycline used for?

Doxycycline for acne:

Doxycycline is the oral antibiotic for acne that is most frequently prescribed by dermatologists in the United States. The American Academy of Dermatology acne guidelines recommend doxycycline as add on treatment for moderate to severe acne and for inflammatory acne resistant to topical treatments. Most who use doxycycline for acne treatment achieve at least a moderate improvement.

Doxycycline for sinus infection:

Doxycycline is not typically prescribed as a first option for a sinus infection. Most patients only require observation and symptom management for uncomplicated sinus infections, as these are often caused by viruses and not bacteria. Doxycycline can be prescribed for a bacterial sinus infection if a patient has a penicillin allergy. Doxycycline’s efficacy in sinus infection treatment depends on the specific bacteria involved.

What are the side effects of doxycycline?

Common side effects of doxycycline include nausea, vomiting, and diarrhea. Doxycycline increases the sensitivity of the skin to sunlight. It is important to wear sunscreen or barrier clothing when exposed to the sun while taking doxycycline and to stop the medication if you develop a rash in sun-exposed areas. Taking the medication right before bed or with insufficient liquids can cause the capsule or tablet to irritate the esophagus.

Doxycycline Interactions

Some medicines that can interact with doxycycline are antacids and supplements that contain calcium, iron, magnesium, zinc, or sodium bicarbonate. If you take products containing these minerals within two hours of the time you take doxycycline, these medicines could decrease doxycycline’s effectiveness. Birth control pills also may not work as well if you are taking doxycycline, so other forms of birth control should be used while you are taking this medicine. 

What foods can I eat while taking doxycycline?

Some foods you should avoid taking with doxycycline include milk, butter, cheese, eggs, kale, and spinach. If consuming any of these foods, eat or drink them two hours before or four hours after you take doxycycline.

Can I drink alcohol while taking doxycycline?

Avoid drinking alcohol while on doxycycline in order to ensure maximum antibiotic effectiveness. Chronic alcohol ingestion may decrease the effectiveness of doxycycline. One study showed that the doxycycline blood level needed to treat an infection dropped to an ineffective level in patients who chronically drank alcohol. Occasional ingestion of alcohol does not appear to interfere with doxycycline.

Is it safe to take doxycycline while pregnant?

Doxycycline should generally be avoided during pregnancy. There are rare exceptions, such as when a woman is exposed to anthrax and is unable to take a first-line antibiotic. Doxycycline crosses the placenta and may cause fetal harm. Taking doxycycline during the last half of pregnancy can cause permanent yellow/gray/brown tooth discoloration in the fetus. Tooth enamel may not properly develop in babies whose mothers took doxycycline while pregnant. In addition, taking doxycycline early in pregnancy may delay bone development in the fetus.

Can you overdose on doxycycline?

There are no published reports of toxic effects in humans who overdose with single large doses of doxycycline. There is one case with chronic overdose causing severe, reversible toxicity. It is curious that calves who are accidentally given three to ten times the therapeutic dose often develop a serious or fatal heart condition. To date, this has not been reported in humans.

Can young children take doxycycline?

Historically, doxycycline was not recommended for use in young children (those less than 8 years of age) due to its potential to cause discoloration and staining of developing teeth. However, recent research has shown that this is unlikely to occur. The American Academy of Pediatrics agrees that short-term (21 days or less) use of doxycycline is safe for children less than 8 years of age.

What should I do if I accidentally take doxycycline or take too much doxycycline?

If you experience adverse or unexpected symptoms from doxycycline, use the webPOISONCONTROL® online tool to get help, or call your poison center at 1-800-222-1222. Whether online or by phone, expert guidance is always free, confidential, and available 24 hours a day.

References

Graber, E. Acne vulgaris: Overview of management. UpToDate. Updated 2022 May 2. 

Leyden JJ, Bruce S, Lee CS, Ling M, Sheth PB, Stewart DM, Werschler WP, Gilbert RD, Kircik L. A randomized, phase 2, dose-ranging study in the treatment of moderate to severe inflammatory facial acne vulgaris with doxycycline calcium. J Drugs Dermatol. 2013 Jun 1;12(6):658-63. PMID: 23839182.

Patel ZM, Hwang PH. Uncomplicated acute sinusitis and rhinosinusitis in adults: Treatment. UptoDate. Updated 2021 Jun 15.

Rosenfeld RM, Piccirillo JF, Chandrasekhar SS, Brook I, Ashok Kumar K, Kramper M, Orlandi RR, Palmer JN, Patel ZM, Peters A, Walsh SA, Corrigan MD. Clinical practice guideline (update): adult sinusitis. Otolaryngol Head Neck Surg. 2015 Apr;152(2 Suppl):S1-S39. doi: 10.1177/0194599815572097. PMID: 25832968.

Schwebke JR, Rompalo A, Taylor S, Seña AC, Martin DH, Lopez LM, Lensing S, Lee JY. Re-evaluating the treatment of nongonococcal urethritis: emphasizing emerging pathogens--a randomized clinical trial. Clin Infect Dis. 2011 Jan 15;52 (2):163-70. doi: 10.1093/cid/ciq074. PMID: 21288838; PMCID: PMC3106252.

Stultz JS, Eiland LS. Doxycycline and Tooth Discoloration in Children: Changing of Recommendations Based on Evidence of Safety. Ann Pharmacother. 2019 Nov;53(11):1162-1166.

Todd SR, Dahlgren FS, Traeger MS, Beltrán-Aguilar ED, Marianos DW, Hamilton C, McQuiston JH, Regan JJ. No visible dental staining in children treated with doxycycline for suspected Rocky Mountain Spotted Fever. J Pediatr. 2015 May;166(5):1246-51. 

Westermann GW, Böhm M, Bonsmann G, Rahn KH, Kisters K. Chronic intoxication by doxycycline use for more than 12 years. J Intern Med. 1999 Dec;246(6):591-2.

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