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Published in Caroline Ashley, Aileen Dunleavy, John Cunningham, The Renal Drug Handbook, 2018
Caroline Ashley, Aileen Dunleavy, John Cunningham
In pharmacokinetic studies it has been demonstrated that the concentrations of azithromycin measured in tissues are noticeably higher (as much as 50 times) than those measured in plasma, which indicates that the agent strongly binds to tissues. Azithromycin is excreted in bile mainly as unchanged drug. Ten metabolites have also been detected in bile, which are formed through N- and O- demethylation in the liver, hydroxylation of desosamine – and aglycone rings and cleavage of cladinose conjugate. The metabolites of azithromycin are not microbiologically active.
Erythromycin
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Interaction occurs via the formation of hydrogen bonds between the reactive groups (2′-OH) of the desosamine sugar and the lactone ring (Schlunzen et al., 2001) and adenine residue 2058. This explains why mutation or methylation in position 2058 as well as mutations in proteins L4 and L22 confer resistance to macrolides. The binding site of the macrolide drug on the ribosome overlaps that of chloramphenicol and those of lincosamides such as clindamycin (Schlunzen et al., 2001), explaining pharmacologic antagonism between these antibiotic classes as well as cross-resistance.
Macrolides and Ketolides
Published in Thomas T. Yoshikawa, Shobita Rajagopalan, Antibiotic Therapy for Geriatric Patients, 2005
Charles Huynh, Shobita Rajagopalan
The first macrolide, erythromycin, was isolated in 1952 from a strain of Streptomyces erythreus found in the Philippine islands (17). It consists of a 14-membered macro-cyclic lactone ring attached to two sugar moieties, desosamine and cladonose (18). Erythromycin is very poorly soluble in water; it is poorly absorbed from the GI tract and is rapidly inactivated by gastric acid. Thus, it is generally recommended with meals (17,18).
Macrolides for KCNJ5–mutated aldosterone-producing adenoma (MAPA): design of a study for personalized diagnosis of primary aldosteronism
Published in Blood Pressure, 2018
Giuseppe Maiolino, Giulio Ceolotto, Michele Battistel, Giulio Barbiero, Maurizio Cesari, Laurence Amar, Brasilina Caroccia, Roberto Padrini, Michel Azizi, Gian Paolo Rossi
The recent discovery that G151R and L168R, the most common KCNJ5 mutations render the Kir3.4 channel exquisitely sensitive to inhibition by some macrolide antibiotics and some of their non-antibiotic derivatives. These agents blunted concentration-dependently aldosterone production in vitro in HAC-15 cells transfected with heterodimers carrying these two mutations provided ground-breaking evidence that the altered physiology of this channelopathy could be corrected by a specific pharmacologic intervention with commonly used macrolides [11]. These antibiotics feature a many-membered lactone ring with one or more deoxy sugars attached [19] and exerts their antibacterial activity by inhibiting protein synthesis by binding of the desosamine sugar and the lactone ring to bacterial 23S ribosomal RNA [20]. Binding to other targets produces anti-inflammatory activity [21], which can have clinical utility, and stimulation of gastrointestinal motility that can cause side effects [22]. A systematic analysis of 14 different macrolides showed that clarithromycin and roxithromycin were among the most potent macrolide antibiotics to inhibit the Kir3.4 channel with G151R and L168R mutations [11].