I have mentioned a few times in the past that the way that metrogel helps rosacea is unknown. This statement deserves some clarification. Actually the way that metronidazole works is well known. How the effect of metrogel leads to a benefit in rosacea, well, that is something worth exploring some more later on.
You may wonder why there is so much emphasis on the metronidazole based products ? As much as metrogel and its friends metrocream, metrolotion, rozex, noritate (and indeed generic metrogel, also from fougera) are not a panacea for rosacea, they do represent the single most proven treatment specifically for rosacea. Thus newly diagnosed rosacea sufferers are quite likely to leave their doctor's surgery with a script for metro-something. All the studies show that in many cases metrogel does indeed work. Further, other studies clearly show that combining metrogel with antibiotics results in better clearance.
So back to `how does it work ?' Well my one sentence summary is "metronidazole breaks down into a substance that kills the DNA of the cells of some particular bacteria and protozoa".
Thanks to Dan for sending me the following links ;
Pharmacology: Metronidazole, a synthetic antibacterial and antiprotozoal agent of the nitroimidazole class, is used against protozoa such as Trichomonas vaginalis, amebiasis, and giardiasis. Metronidazole is extremely effective against anaerobic bacterial infections and is also used to treat Crohn's disease, antibiotic-associated diarrhea, and rosacea.
Mechanism of Action: Unionized metronidazole is selective for anaerobic bacteria due to their ability to intracellularly reduce metronidazole to its active form. This reduced metronidazole then disrupts DNA's helical structure, inhibiting bacterial nucleic acid synthesis and resulting in bacterial cell death.
From Antibiotics that Inhibit Nucleic Acid Synthesis
Figure 11-8. Structure of metronidazole and its mechanism of action. Metronidazole enters an aerobic bacterium where, via the electron transport protein ferrodoxin, it is reduced. The drug then binds to DNA, and DNA breakage occurs.
(An anaerobic organism is any organism that does not require oxygen for growth. Protozoa are a particular type of single cell organisms.)
This naturally leads to the followup question - if eliminating the substances that metronidazole (and for the purposes of this argument, lets include systemic antibiotics as well) is active against leads to relief from some rosacea symptoms, what does that say about the possible cause of rosacea ? Now, that is a question that there isn't much agreement about and something worth talking about some more, later.
Further Reading ;
- focus on metronidazole
- metrogel less irritating than finacea
- collagenex: rosacea is a chronic inflammatory disease
- 1 percent metrogel from galderma
- generic metrogel soon - Fougera
- metrogel, metrolotion, metrocream, noritate, once and twice per day - all the same same
- focus on finacea (azelaic acid 15%)
- periostat and metrogel better than metrogel alone
- low dose doxycycline hyclate (SDD)
