Erythrocin/Erythroped

Retinoid. Isotretinoin is a stereoisomer of all-trans retinoic acid (tretinoin). The exact mechanism of action of isotretinoin has not yet been elucidated in detail, but it has been established that the improvement observed in the clinical picture of severe acne is associated with suppression of sebaceous gland activity and a histologically demonstrated reduction in the size of the sebaceous glands. Furthermore, a dermal anti-inflammatory effect of isotretinoin has been established

Minocin MR capsules contain the active ingredient minocycline as minocycline hydrochloride, which is a semi-synthetic derivative of tetracycline

Tetralysal contains 408mg of lymecycline, equivalent to 300mg tetracycline base. Tetracyclines provide bacteriostatic action at the available plasma and tissue concentrations and are effective against intracellular and extracellular organisms. Their mechanism of action is based on the inhibition of ribosomal protein synthesis. Tetracyclines block the access of the bacterial aminoacyl-tRNA to the mRNA-ribosome complex by binding to the 30S subunit of the ribosome, thus preventing the addition of amino acids to the growing peptide chain in protein synthesis. When given at therapeutically attainable concentrations, their toxic effect is limited to the bacterial cells. The exact mechanisms by which tetracyclines reduce lesions of acne vulgaris have not been fully elucidated, however, the effect appears to result in part from antibacterial activity. Following oral administration, the drugs inhibit the growth of susceptible organisms (mainly Propionibacterium acnes) on the surface of the skin and reduce the concentration of free fatty acids in sebum. The reduction in free fatty acids in sebum may be an indirect result of the inhibition of lipase-producing organisms which convert triglycerides into free fatty acids or maybe a direct result of interference with lipase production in these organisms. Free fatty acids are comedogenic, and are believed to be a possible cause of the inflammatory lesions, e.g. papules, pustules, nodules, cysts, or acne. However, other mechanisms also appear to be involved because clinical improvement of acne vulgaris with oral tetracycline therapy does not necessarily correspond with a reduction in the bacterial flora of the skin or a decrease in the free fatty acid content of sebum

Vibramycin is primarily bacteriostatic and is believed to exert its antimicrobial effect by the inhibition of protein synthesis. Vibramycin is active against a wide range of Gram-positive and Gram-negative bacteria and certain other micro-organisms.