Clarithromycin is an oral antibiotic drug used for the treatment of bacterial infections including acute otitis media caused by H. influenzae, M. catarrhalis, or S. pneumoniae in patients with a history of type I penicillin hypersensitivity, pharyngitis and tonsillitis caused by susceptible Streptococcus pyogenes, respiratory tract infections including acute maxillary sinusitis, acute bacterial exacerbations of chronic bronchitis, mild to moderate community-acquired pneuomia, Legionnaires' disease, and pertussis, skin or skin structure infections, helicobacter pylori infection, duodenal ulcer disease, bartonella infections, early Lyme disease, and encephalitis caused by Toxoplasma gondii (in HIV infected patients in conjunction with pyrimethamine). Clarithromycin is metabolized in the liver to 14-OH clarithromycin by cytochrome P450 3A4 enzymes. Clarithromycin and 14-OH clarithromycin then penetrate the bacterial cell wall and act synergistically to inhibit protein synthesis. These compounds act by binding to domain V of the 23S ribosomal RNA of the 50S subunit of the bacterial ribosome. This inhibits translocation of the aminoacyl transfer-RNA, preventing the addition of the next amino acid to the growing polypeptide chain. As a result, protein synthesis is inhibited, preventing bacterial growth and this may even kill the bacteria. Whether clarithromycin is bacteriostatic or bactericidal depends on the organism and the concentration used. Common side effects from taking clarithromycin include nausea, abdominal pain, diarrhea, dyspepsia, headache, dizziness, angioedema and rash.

Clarithromycin Anti-bacterial Pathway References