Rifamycin SV is a derivative of antibiotic rifamycin B (the natural fermentation product of S. mediterranei broths). The primary target of rifampicin on whole bacteria is the synthesis of RNA. Rifamycin belongs to the ansamycin class of antibacterial drugs and acts by inhibiting the beta subunit of the bacterial DNA-dependent RNA polymerase, blocking one of the steps in DNA transcription. This results in inhibition of bacterial synthesis and consequently growth of bacteria. Rifampicin exhibits bactericidal activity on Gram-positive and Gram-negative bacteria and on mycobacteria. Rifamycin SV MMX® (AEMCOLO), a non-absorbable rifamycin antibiotic formulated using the multi-matrix system, was designed to exhibit its pharmacological action on the distal small intestine and colon. AEMCOLO is indicated for the treatment of travelers’ diarrhea (TD) caused by non-invasive strains of Escherichia coli in adults.

Sparfloxacin is a synthetic fluoroquinolone broad-spectrum antimicrobial agent in the same class as ofloxacin and norfloxacin. Sparfloxacin has in vitro activity against a wide range of gram-negative and gram-positive microorganisms. Sparfloxacin exerts its antibacterial activity by inhibiting DNA gyrase, a bacterial topoisomerase. DNA gyrase is an essential enzyme which controls DNA topology and assists in DNA replication, repair, deactivation, and transcription. Quinolones differ in chemical structure and mode of action from (beta)-lactam antibiotics. Quinolones may, therefore, be active against bacteria resistant to (beta)-lactam antibiotics. Although cross-resistance has been observed between sparfloxacin and other fluoroquinolones, some microorganisms resistant to other fluoroquinolones may be susceptible to sparfloxacin. In vitro tests show that the combination of sparfloxacin and rifampin is antagonistic against Staphylococcus aureus. The bactericidal action of sparfloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination. Sparfloxacin is used for the treatment of adults with the following infections caused by susceptible strains microorganisms: community-acquired pneumonia (caused by Chlamydia pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, or Streptococcus pneumoniae) and acute bacterial exacerbations of chronic bronchitis (caused by Chlamydia pneumoniae, Enterobacter cloacae, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis,Staphylococcus aureus, or Streptococcus pneumoniae). Sparfloxacin has trade names Spacin in Bangladesh, Zagam and Zagam Respipac. Zagam is no longer available in the United States.

Phenyl Aminosalicylate is the phenyl ester of para-aminosalicylic acid, reported to have less side effects than simple salts of para-aminosalicylic acid. It’s a second-line antituberculosis drug with a high incidence of hypersensitivity reactions and gastrointestinal upset.

Benzoylpas (more known as calcium benzoyl-PAS) is a benzoic acid-modified form of para-aminosalicylate, used to treat pulmonary tuberculosis.

Potassium Aminosalicylate is the potassium salt form of aminosalicylic acid, an analog of aminobenzoic acid used to treat tuberculosis. There are two mechanisms responsible for aminosalicylic acid's bacteriostatic action against Mycobacterium tuberculosis. Firstly, aminosalicylic acid inhibits folic acid synthesis (without potentiation with antifolic compounds). The binding of para-aminobenzoic acid to pteridine synthetase acts as the first step in the folic acid synthesis. Aminosalicylic acid binds pteridine synthetase with greater affinity than para-aminobenzoic acid, effectively inhibiting the synthesis of folic acid. As bacteria are unable to use external sources of folic acid, cell growth and multiplication slow. Secondly, aminosalicylic acid may inhibit the synthesis of the cell wall component, mycobactin, thus reducing iron uptake by M. tuberculosis. Specifically, Potassium Aminosalicylate is used to treat active drug-resistant tuberculosis together with other antituberculosis medications. Potassium Aminosalicylate t has also been used as a second line agent to sulfasalazine in people with inflammatory bowel disease such as ulcerative colitis and Crohn's disease.

Viomycin is a basic peptide antibiotic, which is among the most effective agents against multidrug-resistant tuberculosis. The tuberactinomycins, such as Viomycin, target bacterial ribosomes, binding RNA and disrupting bacterial protein biosynthesis. Specifically, viomycin binds to a site on the ribosome which lies at the interface between helix 44 of the small ribosomal subunit and helix 69 of the large ribosomal subunit. The structures of this complexes suggest that the viomycin inhibits translocation by stabilizing the tRNA in the A site in the pretranslocation state.

Thiocarlide (or tiocarlide or isoxyl) is a drug which was used in the treatment of tuberculosis. In addition was preclinical experiments, which showed, that it purely bacteriostatic against M. leprae. The precise mechanism is still unknown but was shown, that Delta9-desaturase could be a target for it. The more recent experiments have revealed, that Thiocarlide inhibits the dehydration step by the (3R)-hydroxyacyl dehydratases HadAB and HadBC.

Morinamide is a second line anti-tuberculous agent. In vitro morinamide demonstrated clear dose-dependent bacteriostatic and bactericidal activities. The anti-mycobacterial effect of morinamide was the same as pyrazinamide and was dependent on the acidity of medium (pH 5.6). Liver function test abnormalities following morinamide therapy are usually mild, and onset of jaundice is extremely uncommon. It has been given orally as the hydrochloride in the treatment of tuberculosis.

TERIZIDONE, a structural analog of cycloserine, is a broad spectrum antibiotic used in the treatment of multidrug-resistant tuberculosis. However, its effectiveness is widely debated. Terizidone acts by inhibiting cell wall synthesis by competitively inhibiting two enzymes, L-alanine racemase and D-alanine ligase, thereby impairing peptidoglycan formation necessary for bacterial cell wall synthesis.