Doxycycline and Gastrointesintal Side effects: What have we learned ?

Doxycycline for Scarring alopecia

Doxycycline is an antibiotic that has a unique property in that it is also anti-inflammatory. Doxycycline, at doses 100-200 mg is frequently used for treating scarring alopecias such as lichen planopilaris. The side effects of doxycycline must be carefully weighed against the benefits. Typical risks include gastrointestinal upset (including a risk of irritable bowel syndrome, gastritis, nausea, reflux, peptic ulcer disease and small intestine bacterial overgrowth) sun sensitivity, headaches, and weight gain.

I have increasingly been using subantimicrobial (40 mg) dosing of doxycycline in my clinic for patients with scarring alopecias that are entering a stable phase. Subantimicrobial doses of doxycycline are frequently used for treating rosacea. The hope is that by using the subantimicrobial dosing we can maintain benefits on inflammation without the gastointestinal side effects that accompany standard doses. 

I was very interested in a recently study by Hester Gail Lim and colleauges looking at the side effects on the gastrointestinal system with conventional dosing and subantimicrobial dosing of doxycycline.

Compared to conventional dosing, the use of subantimicrobial dosing was associated with a lower risk of gastrointestinal disease including lower irritable bowel syndrome, H. pylori infection, reflux disease, gastritis and peptic ulcer disease.

Importantly, patients using subantimicrobial dosing of doxycycline had similar levels of gastrointestinal disease to those who weren’t using these drugs at all.  Specifically, the incidence of celiac disease, irritable bowel disease, bacterial overgrowth, reflux disease and gastritis were not increased in those using subantimicrobial dosing. 



The goal of any treatment should be to keep the patient on the medication for as short of duration as needed. For many patients using doxycycline who can not quite quickly withouth risk of flare, the use of subantimicrobial dosing presents a treatment option. This study is encouraging that low dose doxycycline may not increase the risk of gastrointestinal disease. 

Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887

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