Telithromycin: the first ketolide for the treatment of respiratory infections

The pharmacology, mechanisms of resistance, in vitro activity, clinical efficacy, pharmacokinetics, indications, adverse effects, dosage and administration, and place in therapy of telithromycin in the treatment of respiratory infections are reviewed.

Telithromycin is the first ketolide to be approved in the United States for use against common respiratory pathogens. The unique structure of telithromycin allows for enhanced binding to bacterial ribosomal RNA, thereby blocking protein synthesis. Its spectrum of activity includes pathogens implicated in common respiratory infections (Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumonia, and Chlamydia pneumoniae) and multidrug-resistant isolates of pneumococcus. Clinical efficacy has been documented in several multicenter, comparative trials for the treatment of community-acquired pneumonia, acute exacerbation of chronic bronchitis, acute maxillary sinusitis, and pharyngitis tonsillitis. Although studies have demonstrated that the clinical efficacy of telithromycin is comparable to macrolides, telithromycin is unique in that it provides activity against penicillin- and macrolide-resistant respiratory pathogens. The recommended dosage of telithromycin is 800 mg p.o. once daily. The most common adverse events resulting from telithromycin use include diarrhea, nausea, headache, dizziness, vomiting, loose stools, dysgeusia, and dyspepsia. The drug's adverse-event profile is comparable to that of similar agents. Telithromycin is a strong inhibitor of cytochrome P-450 isoenzyme 3A4; therefore, it can affect the efficacy and toxicity profile of medications that are metabolized by this isoenzyme.

Telithromycin is a reasonable addition to the current treatment options for upper-respiratory-tract infections. Its use should be restricted to infections caused by penicillin- and macrolide-resistant pathogens.