Minocycline is a tetracycline analog, having a 7-dimethylamino and lacking the 5 methyl and hydroxyl groups, which is effective against tetracycline-resistant staphylococcus infections. Minocycline has many brand names one of them is minocin, Minocin is indicated in the treatment of the following infections due to susceptible isolates of the designated bacteria: Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox and tick fevers caused by rickettsiae. Respiratory tract infections caused by Mycoplasma pneumoniae. Lymphogranuloma venereum caused by Chlamydia trachomatis. Psittacosis (Ornithosis) due to Chlamydophila psittaci etc. Minocycline is indicated for the treatment of infections caused by the following Gram-negative bacteria when bacteriologic testing indicates appropriate susceptibility to the drug: Escherichia coli. Enterobacter aerogenes. Shigella species etc. MINOCIN also is indicated for the treatment of infections caused by the following Gram-positive bacteria when bacteriologic testing indicates appropriate susceptibility to the drug: Upper respiratory tract infections caused by Streptococcus pneumoniae. Skin and skin structure infections caused by Staphylococcus aureus (Note: Minocycline is not the drug of choice in the treatment of any type of staphylococcal infection, etc. When penicillin is contraindicated, minocycline is an alternative drug in the treatment of the following infections: Meningitis due to Neisseria meningitidis. Syphilis caused by Treponema pallidum subspecies pallidum. Yaws caused by Treponema pallidum subspecies pertenue, etc. Minocycline passes directly through the lipid bilayer or passively diffuses through porin channels in the bacterial membrane. Minocycline inhibits protein synthesis by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria.

Tigecycline (INN) is an antibiotic used to treat a number of bacterial infections. It is a first in class glycylcycline that is administered intravenously. For the treatment of infections caused by susceptible strains of the designated microorganisms in the following conditions: Complicated skin and skin structure infections caused by Escherichia coli, Enterococcus faecalis (vancomycin-susceptible isolates only), Staphylococcus aureus (methicillin-susceptible and -resistant isolates), Streptococcus agalactiae, Streptococcus anginosus grp. (includes S. anginosus, S. intermedius, and S. constellatus), Streptococcus pyogenes and Bacteroides fragilis. Complicated intra-abdominal infections caused by Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Enterococcus faecalis (vancomycin-susceptible isolates only), Staphylococcus aureus (methicillin-susceptible isolates only), Streptococcus anginosus grp. (includes S. anginosus, S. intermedius, and S. constellatus), Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides uniformis, Bacteroides vulgatus, Clostridium perfringens, and Peptostreptococcus micros. Tigecycline, a glycylcycline, inhibits protein translation in bacteria by binding to the 30S ribosomal subunit and blocking entry of amino-acyl tRNA molecules into the A site of the ribosome. This prevents incorporation of amino acid residues into elongating peptide chains. Tigecycline carries a glycylamido moiety attached to the 9-position of minocycline. The substitution pattern is not present in any naturally occurring or semisynthetic tetracycline and imparts certain microbiologic properties to tigecycline. In general, tigecycline is considered bacteriostatic; however, TYGACIL has demonstrated bactericidal activity against isolates of S. pneumoniae and L. pneumophila. In vitro studies have not demonstrated antagonism between tigecycline and other commonly used antibacterials.

Minocycline is a tetracycline analog, having a 7-dimethylamino and lacking the 5 methyl and hydroxyl groups, which is effective against tetracycline-resistant staphylococcus infections. Minocycline has many brand names one of them is minocin, Minocin is indicated in the treatment of the following infections due to susceptible isolates of the designated bacteria: Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox and tick fevers caused by rickettsiae. Respiratory tract infections caused by Mycoplasma pneumoniae. Lymphogranuloma venereum caused by Chlamydia trachomatis. Psittacosis (Ornithosis) due to Chlamydophila psittaci etc. Minocycline is indicated for the treatment of infections caused by the following Gram-negative bacteria when bacteriologic testing indicates appropriate susceptibility to the drug: Escherichia coli. Enterobacter aerogenes. Shigella species etc. MINOCIN also is indicated for the treatment of infections caused by the following Gram-positive bacteria when bacteriologic testing indicates appropriate susceptibility to the drug: Upper respiratory tract infections caused by Streptococcus pneumoniae. Skin and skin structure infections caused by Staphylococcus aureus (Note: Minocycline is not the drug of choice in the treatment of any type of staphylococcal infection, etc. When penicillin is contraindicated, minocycline is an alternative drug in the treatment of the following infections: Meningitis due to Neisseria meningitidis. Syphilis caused by Treponema pallidum subspecies pallidum. Yaws caused by Treponema pallidum subspecies pertenue, etc. Minocycline passes directly through the lipid bilayer or passively diffuses through porin channels in the bacterial membrane. Minocycline inhibits protein synthesis by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria.

Doxycycline is an antibacterial drug synthetically derived from oxytetracycline and used to treat a wide variety of bacterial infections, including those that cause acne. Doxycycline is used for bacterial pneumonia, acne, chlamydia infections, early Lyme disease, cholera, and syphilis. It is also useful for the treatment of malaria when used with quinine and for the prevention of malaria. Common side effects include diarrhea, nausea, vomiting, a red rash, and an increased risk of a sunburn. If used during pregnancy or in young children may result in permanent problems with the teeth including changes in their color. Its use during breastfeeding is probably safe. Like other tetracycline antibiotics, Doxycycline is protein synthesis inhibitors, inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex by binding to the 30S ribosomal subunit in the mRNA translation complex.