What is the role of tetracyclines in ocular rosacea treatment?

Updated: Mar 03, 2020
  • Author: Jitander Dudee, MD, MA(Cantab), FACS, FRCOphth; Chief Editor: Edsel Ing, MD, MPH, FRCSC  more...
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Answer

Tetracyclines (eg, tetracycline, doxycycline, minocycline)  [23, 20, 24]

Tetracyclines represent the most common and most effective treatment regimen for rosacea. These drugs are believed to be effective not primarily as antibiotics but rather through a secondary effect that they exert on the meibomian glands. Tetracyclines decrease bacterial lipase, thereby altering the fatty acid composition of the meibomian gland secretions and improving their solubility. These medications also inhibit collagenase; therefore, they are effective in protecting the cornea from impending perforation secondary to inflammatory responses.

Adverse effects are predominantly GI, including diarrhea and, rarely, pancreatitis and pseudomembranous colitis. In these patients, enteric-coated tetracyclines such as Doryx (a form of enteric-coated doxycycline) are a promising option. The special coating prevents the medication from dissolving in the stomach where it may induce GI upset. Instead, the medication is broken down in the small intestine from where it readily enters the blood stream. More severe but much less common adverse effects include benign intracranial hypertension and renal tubular damage (Fanconi syndrome) from outdated medications. Additionally, tetracyclines cross the placenta and can cause permanent discoloration of teeth as well as fetal bone growth retardation.

Tetracyclines generally are effective for rosacea in doses much lower than those given for antibiotic effect, and, once the disease has come under control, the dose may be tapered to a lower, suppressive dose and maintained indefinitely. Because of the chronic, relapsing nature of rosacea, the medication may be used chronically at suppressive doses or discontinued and restarted if and when symptoms recur.

Among this class of medications, tetracycline and doxycycline are most commonly used. These two medications are quite similar in their mechanism of action, adverse effect profile, and efficacy, but slight differences do exist. Tetracycline has a shorter half-life and, thus, is dosed 4 times per day, as opposed to doxycycline, which is given twice per day or once per day. Frucht-Pery et al reported a more rapid therapeutic response to tetracycline; however, no difference was found at 6 months. [15]

In 2006, the first FDA-approved oral treatment for rosacea became available: a controlled-release form of doxycycline called Oracea (Galderma Laboratories L.P). The 40-mg tablet is a combination of 30 mg of immediate-release and 10 mg of delayed-release doxycycline. The low dose enables the medication to have anti-inflammatory properties without exerting significant antibacterial properties, allowing for a more improved side effect profile and decrease rates of bacterial resistance.

Topical azithromycin eye drops have also gained popularity in the treatment of ocular rosacea. Ocular rosacea often results in severe and recalcitrant blepharitis. Azasite (azithromycin 1%, Inspire Pharmaceuticals) currently FDA approved only to treat bacterial conjunctivitis has found an off label use in the treatment of meibomian gland dysfunction.

Erythromycin can be taken orally for patients intolerant to, or too young for, tetracyclines. Erythromycin ointment applied to the lid margins once or twice daily can provide lubrication for the eye and reduce the bacterial overgrowth contributing to lid margin disease.

Clarithromycin has shown efficacy in treating rosacea. This compound exhibits anti-inflammatory effects as well as activity against H pylori. Torresani compared clarithromycin and doxycycline and found equivalent therapeutic responses and a milder adverse effect profile for clarithromycin. [25]


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