Rifampin antibacterial activity

Ansamacrolides. Antibiotics ia the ansamacroHde family ate also referred to as ansamycias. They are benzenoid or naphthalenoid aromatic compounds ia which nonadjacent positions are bridged by an aliphatic chain to form a cycHc stmcture. One of the aliphatic—aromatic junctions is always an amide bond. Rifampin is a semisyntheticaHy derived member of this family and has clinical importance. It has selective antibacterial activity and inhibits RNA polymerase. 

The broad antibacterial activity of rifaximin as well as its topical action make this antibiotic suitable for intrapocket administration in periodontal disease. As a matter of fact, local application of rifaximin compares well with tetracyclines and metronidazole in other extra-GI diseases, i.e. skin infections and BY, respectively (see above). On the other hand, rifampicin (rifampin), another rifamy-cin derivative, has been successfully used in the treatment... 

Rifampin. Source, antibacterial activity, and routes of administration are described on p. 274. Albeit mostly well tolerated, this drug may cause several adverse effects including hepatic damage, hypersensitivity with flu-like symptoms, disconcerting but harmless red/orange discoloration of body fluids, and enzyme induction (failure of oral Liillmann, Color Atlas of Pharmacology... 

Rifampin is metabolized in the liver to a deacetylated metabolite that also has antibacterial activity. Unchanged drug and the active metabolite are eliminated primarily in bile, but up to 30% may be excreted in urine. The parent drug undergoes extensive enterohepatic recirculation, but the metabolite does not. The half-life of rifampin is 6-8 h in adult horses and 17h in foals. Repeated dosing results in a decrease in the half-life of rifampin through induction of hepatic enzymes this may also affect the metabolism of concurrently administered drugs. 

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