Clarithromycin, a semisynthetic macrolide antibiotic derived from erythromycin, inhibits bacterial protein synthesis by binding to the bacterial 50S ribosomal subunit. Binding inhibits peptidyl transferase activity and interferes with amino acid translocation during the translation and protein assembly process. Clarithromycin may be bacteriostatic or bactericidal depending on the organism and drug concentration.
Act Clarithromycin XL
Enteric bacteria and other eubacteria
An alternative medication for the treatment of acute otitis media caused by <i>H. influenzae, M. catarrhalis, or S. pneumoniae</i> in patients with a history of type I penicillin hypersensitivity. Also for the treatment of pharyngitis and tonsillitis caused by susceptible <i>Streptococcus pyogenes</i>, as well as respiratory tract infections including acute maxillary sinusitis, acute bacterial exacerbations of chronic bronchitis, mild to moderate community-acquired pneuomia, Legionnaires' disease, and pertussis. Other indications include treatment of uncomplicated skin or skin structure infections, helicobacter pylori infection, duodenal ulcer disease, bartonella infections, early Lyme disease, and encephalitis caused by <i>Toxoplasma gondii</i> (in HIV infected patients in conjunction with pyrimethamine). Clarithromycin may also decrease the incidence of cryptosporidiosis, prevent the occurence of α-hemolytic (viridans group) streptococcal endocarditis, as well as serve as a primary prevention for <i>Mycobacterium avium</i> complex (MAC) bacteremia or disseminated infections (in adults, adolescents, and children with advanced HIV infection).
Clarithromycin is a macrolide antibiotic whose spectrum of activity includes many gram-positive (<i>Staphylococcus aureus, S. pneumoniae, and S. pyogenes</i>) and gram-negative aerobic bacteria (<i>Haemophilus influenzae, H. parainfluenzae, and Moraxella catarrhalis</i>), many anaerobic bacteria, some mycobacteria, and some other organisms including <i>Mycoplasma, Ureaplasma, Chlamydia, Toxoplasma</i>, and <i>Borrelia</i>. Other aerobic bacteria that clarithromycin has activity against include <i>C. pneumoniae and M. pneumoniae</i>. Clarithromycin has an in-vitro activity that is similar or greater than that of erythromycin against erythromycin-susceptible organisms. Clarithromycin is usually bacteriostatic, but may be bactericidal depending on the organism and the drug concentration.
Mechanism of action
Clarithromycin is first metabolized to 14-OH clarithromycin, which is active and works synergistically with its parent compound. Like other macrolides, it then penetrates bacteria cell wall and reversibly binds to domain V of the 23S ribosomal RNA of the 50S subunit of the bacterial ribosome, blocking translocation of aminoacyl transfer-RNA and polypeptide synthesis. Clarithromycin also inhibits the hepatic microsomal CYP3A4 isoenzyme and P-glycoprotein, an energy-dependent drug efflux pump.
Drug Info/Drug Targets: DrugBank 3.0: a comprehensive resource for 'omics' research on drugs. Knox C, Law V, Jewison
T, Liu P, Ly S, Frolkis A, Pon A, Banco K, Mak C, Neveu V, Djoumbou Y, Eisner R, Guo AC, Wishart DS.
Nucleic Acids Res. 2011 Jan; 39 (Database issue):D1035-41. | PMID:21059682