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Rifamycin
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Rifamycin is the prime member of the rifamycin family which are represented by drugs that are a product of fermentation from the gram-positive bacterium Amycolatopsis mediterranei, also known as Streptomyces mediterranei. Rifamycin has an activity spectrum against gram-positive and gram-negative bacteria, including Mycobacterium species (especially M. tuberculosis). Rifamycin is indicated for the treatment of adult patients with travelers’ diarrhea caused by non-invasive strains of E. coli. It is also used in tuberculosis in association with other agents to overcome resistance (1). In pharmaceutical products, rifamycin is employed as rifamycin sodium (CAS number 14897-39-3, EC number 238-965-7, molecular formula C37H46NNaO12) (1). It is (or was) also used in topical pharmaceuticals in Italy and France as a 0.5% solution, often used on leg ulcers (4,5). Topical rifamycin is currently available in Brazil for infected wounds (8), (with lidocaine) in Taiwan (www.drugs.com) and possibly in other countries.
Tuberculosis in Childhood and Pregnancy
Published in Lloyd N. Friedman, Martin Dedicoat, Peter D. O. Davies, Clinical Tuberculosis, 2020
Lindsay H. Cameron, Jeffrey R. Starke
Rifampin and rifapentine are rifamycins that are also well tolerated by children. Hepatotoxicity is infrequent and other adverse reactions that occur in adults, including leukopenia, thrombocytopenia and immunologically mediated flu-like syndrome, are rare. Clinicians should consider the risk of drug-drug interactions as rifamycins may influence the metabolism of various classes of medications (including antiretroviral medications, antiepileptic medications, and antihypertensive medications). In addition, the effectiveness of most oral contraceptives will be decreased, and alternative birth control methods should be used.
Physiology and Growth
Published in Paul Pumpens, Single-Stranded RNA Phages, 2020
Later, Engelberg et al. (1975) found a discriminative effect of rifamycin on RNA replication of various RNA phages. According to this study, rifamycin interfered exclusively with the RNA replication in vivo of the group I phages MS2, f2, and R17, whereas Qβ RNA replication was not affected by the drug. In addition, rifamycin was found to have a discriminative effect on the group I phage RNA replication: the antibiotic differentially interfered with the synthesis of minus RNA strands of the phage f2, whereas it had almost no effect on the synthesis of the progeny plus strands. For the phage MS2, the drug differentially arrested the synthesis of the progeny plus strands and almost failed to affect the synthesis of the minus RNA strands. For the phage R17, both steps of its RNA replication were affected by rifamycin, although each step was only partially (approximately 50%) inhibited (Engelberg et al. 1975).
Chapter 6: Tuberculosis preventive treatment in adults
Published in Canadian Journal of Respiratory, Critical Care, and Sleep Medicine, 2022
Gonzalo G. Alvarez, Christopher Pease, Dick Menzies
All rifamycin-based regimens have important drug-drug interactions because rifamycins are inducers of hepatic metabolizing enzymes, including cytochrome P450 enzymes, which can result in increased elimination of many other medications. Some of the important categories of interacting medications include many antihypertensives, anticoagulants, antifungal drugs, methadone, some immunosuppressive agents, hormonal contraceptives, antiretrovirals and others. These medications may need to be adjusted, stopped or changed to an alternate medication during TPT. In the case of oral contraception, an alternative form of contraception such as a barrier contraceptive or an intrauterine device should be used during treatment. Practitioners can check for drug-drug interactions with Lexicomp and Micromedex, the two main professional-level tools for doing so. Both are widely used (license required).
Evaluating treatments with rifabutin and amoxicillin for eradication of Helicobacter pylori infection in adults: a systematic review
Published in Expert Opinion on Pharmacotherapy, 2022
Elias Xirouchakis, Sotirios D. Georgopoulos
Rifabutin and its relative rifampin (rifampicin) are spiro-piperidyl forms derived from rifamycin-S [26]. Rifabutin has activity against mycobacteria including Mycobacterium tuberculosis and M. leprae and other atypical Mycobacteria comprised in the Mycobacterium avium complex (MAC) [27]. It is also effective against H. pylori and other Gram-positive and Gram-negative bacteria, Chlamydia trachomatis and Toxoplasma gondii. Rifamycins inhibit DNA transcription through blockage of DNA-dependent RNA polymerase and more often the b-subunit encoded by the rpoB gene. Rifamycins should not be used alone but in combination with other antibiotics [28]. Rifabutin has been approved in US for prophylaxis of MAC disease in HIV patients and in Europe also for treatment of MAC and multidrug-resistant tuberculosis [29].
Repositioning rifamycins for Mycobacterium abscessus lung disease
Published in Expert Opinion on Drug Discovery, 2019
Uday S. Ganapathy, Véronique Dartois, Thomas Dick
As the potency of rifabutin against M. abscessus is likely due to its greater accumulation in the bacterium, rifamycin repositioning efforts should seek to produce a compound with desirable bacterial cell uptake and metabolism. In addition to blocking metabolism (described above), the intra-bacterial levels of rifamycins could be increased by improving uptake or reducing efflux. As recently demonstrated, predictive accumulation assays can inform the addition of structural modifications that improve drug uptake [81]. Bacterial strains that overexpress efflux pump genes can be used to screen and identify compounds that are less prone to efflux [115]. Computational approaches can also be used to compare the binding of compounds to efflux pumps and identify chemical features associated with poor binding [116]. In addition to in vitro potency assays, measurement of intra-bacterial accumulation can help prioritize promising scaffolds and analogs.