Doxycycline Pharmacology and Clinical Pearls


On an episode of the Real Life Pharmacology Podcast, I broke down doxycycline pharmacology and some important aspects that you need to remember as a healthcare professional. Here are a few practice pearls that you need to be aware of.  

Pregnancy and Pediatrics

The age of the patient and the gender of the patient is one of the first things I look at when I am considering recommending doxycycline or assessing a patient who has been ordered the drug.  Doxycycline has typically been avoided due to problems with other members of the tetracycline drug class. I’m still extremely cautious with this, however, here is an interesting read that you should be aware of that discusses some of the evidence (or lack thereof) in patients taking doxycycline.  The article states that no correlation has been found between doxycycline and teratogenic effects.  Certainly, having more options available in pregnancy and pediatrics would be a good thing.  This is something I’m going to watch for more information on over the next few years.  Hopefully, this is further studied.

Binding Interactions

Supplements like iron, calcium, and magnesium can impair absorption the absorption of doxycycline and other tetracycline antibiotics.  These interactions can lead to lower antibiotic concentrations and increase the risk of treatment failure.  I encountered a case of this similar to this with a quinolone antibiotic.


Doxycycline is a classic case of a drug that can increase the sensitivity to “sunburn”.  This can be very problematic in patients who may work outside for a living.  We must educate our patients about this effect and that they need to be extra cautious about this potential effect.


An Answer if you don’t know the Answer

I remember joking in pharmacy school with classmates about the utility of doxycycline in treating less common bacterial infections. If you are taking NAPLEX, BCPS, BCACP, or BCGP soon, we always said, if you’ve never heard of an infection or bacteria and doxycycline is one of the options, odds are likely it covers it. Of course, this isn’t always true, but it sure seems like it!

Some examples of bugs that the drug covers include Borrelia burgdorferi (Lyme’s disease), Rickettsia rickettsii (Rocky Mountain spotted fever), Vibrio cholerae (Cholera), Brucella spp (Mediterranean fever), and Ehrlichia spp.

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Written By Eric Christianson

April 24, 2019

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