Rifampicins

Rifampicin has also shown antiviral activity but at levels 500—1000 times greater than required for antibacterial activity (130,140—142). Rifampicin shows promise in the treatment of leprosy (130,143). A large number of rifampicinlike derivatives are potent inhibitors of reverse transcriptase (123,144-148). 

Rifapentine (DL473) [61379-65-5] (40), C42H34N4O22, a pipera2inyl hydra2one of 3-formyl rifamycin SV, is similar to rifampicin. Rifapentine has activity similar to rifampicin, but its half-life is much longer (149,150). 

A number of oxime derivatives of rifaldehyde have been prepared. Many of these derivatives exhibit good activity against rifampicin-resistant organisms (151,152). 

Rifampicin, the only commercially available ansamacroHde, is manufactured by MerreU Dow under the tradename Rifadin, and by CIBA under the trade name Rimactane. Rifampicin is also suppHed in combination with isoniazid or pyrazinamide [98-96-4]. The rifampicin—isoniazid combination is known as Rifamate (MerreU Dow), Rifinah (MerreU Dow), and Rimactazid (CIBA) the rifampicin—pyrazinamide as Rifater (MerreU Dow). Several other rifamycin derivatives including rifabutin and rifapentine are undergoing clinical studies. 

Common Name 3-[(4-Methyl-1 -piperazinyDiminomethyl] rifamycin SV rifaldazine rifa-mycin AMF rifampicin... 

The co-administration of drugs which induce the metabolic enzymes in the liver or small intestine can reduce the plasma concentrations of drugs which are substrates of the enzyme, leading to reduced drug effects. For example, the plasma concentrations of many drugs which are substrates of the enzyme CYP3A4, such as cyclosporine, are decreased by coadministration of rifampicin, which is an inducer of CYP3A4. 

Nucleotidylation - the addition of adenylate-residues by Lnu enzymes - can also be the cause of resistance to lincosamide antibiotics in staphylococci and enterococci. A plasmid encoded ADP-ribosylating transferase (Arr-2) that leads to rifampicin resistance has been detected in various Enterobacteriaceae as well as in Pseudomonas aeruginosa. 

AcrAB- TolC Tetracycline, fluoroquinolones, chloramphenicol, p-lactams except imipenem, novobiocin, erythromycin, fusidic acid, rifampicin E. coli Chromosome... 

Potassium Competitive Acid Blockers The pregnane X receptor (PXR) is a promiscuous nuclear receptor, that has evolved to protect the body from toxic chemicals. It is activated by a wide variety of xenobiotics including several diugs like rifampicin, hyperforin ( the active ingredient of St. John s wort), clotrimazole and others. PXR heterodimerizes with the... 

Rifa (GrOnenthal 1970) Rifampicin-Hcfa (Hefa Pharma)... 

Chlamydia trachomatis can cause a variety of diseases in humans, for example trachoma, conjunctivitis and non-gonococcal urethritis. It is sensitive to the rifampicins, the tetracyclines and erythromycin. 

Rifampicin possesses significant bactericidal activity at very low eoncentrations against staphylococci. Unfortunately, resistant mutants m arise very rapidly, both in vitro and in vivo. It has thus been reeommended that rifampicin should be eombined with another antibiotie, e.g. vaneomyein, in the treatment of staphylococeal infections. 

Dapsone (diaminodiphenylsulphone Fig. 5.16F) is used specifically in the treatment of leprosy. However, because resistance to dapsone is unfortunately now well known, it is recommended that dapsone be used in conjunction with rifampicin and clofazimine. 

In some infections the pathogenic organisms are located intracellularly within phagocytic cells and, therefore, remain relatively protected from drugs which penetrate cells poorly, such as the penicillins and cephalosporins. In contrast, erythromycin, rifampicin and chloramphenicol readily penetrate phagocytic cells. Legionnaires disease is an example of an intracellular infection and is treated with rifampicin and/or erythromycin. 

Mycobacterium tuberculosis Rifampicin + isoniazid + ethambutol + pyrazinamide ... 

Chromosome function Quinolones Metronidazole (also ) Nitrofu rantoin Rifampicin (also ) 5-Fluorocytosine Inhibit DNA gyrase DNA strand breakage DNA strand breakage Inhibits RNA polymerase Inhibits DNA synthesis No action on mammalian equivalent Requires anaerobic conditions not present in mammalian cells No action on mammalian equivalent Converted to active form in fungi... 

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