Minocycline is a broad-spectrum antibiotic belonging to the tetracycline family. It is used to treat all sorts of infections caused by bacteria, including acne and the papulopustular rosacea. It is a second-generation tetracycline, like the doxycycline. In terms of papulopustular rosacea, a treatment with minocycline allows to reduce the number of papules and pustules, which visibly improves the appearance and texture of the skin. Minocycline is also associated with a reduction in redness, contributing to a better quality of life for patients suffering from rosacea.
From a mechanistic perspective, minocycline is a bacterial protein translation inhibitor. This substance has the ability to cross the bacterial wall, either through porins or by diffusion across the phospholipid layer, before attaching itself to the 30S subunit of the ribosomes. Minocycline thus halts protein synthesis. Deprived of the proteins essential for their growth, the bacteria cease to multiply. This antibacterial property of minocycline is particularly interesting in the case of papulopustular rosacea, a dermatosis which is believed to be influenced by the multiplication of certain microorganisms on the skin surface.
Minocycline also acts on the inflammatory symptoms of rosacea by inhibiting the production of pro-inflammatory cytokines such as interleukins-1 and 6 (IL-1 and IL-6) and tumour necrosis factor (TNF-α) by immune cells. Minocycline can also prevent the degradation of collagen by collagenase-type enzymes, thus reducing tissue damage associated with inflammation. Finally, this substance can modulate certain intracellular signalling pathways, such as the MAPK and NF-κB pathways, playing a role in the regulation of the expression of genes involved in inflammation processes.
Note : Minocycline can cause photosensitisation of the skin. Therefore, it is recommended to apply daily sun protection throughout the treatment. Moreover, it is good to know that minocycline is not advised for pregnant women during the last six months of pregnancy and children under eight years old as it could lead to permanent discolouration of the teeth.