Telavancin (Vibativ - Astellas and Theravance), a lipoglycopeptide derivative of vancomycin (Vancocin, and others), has received FDA approval for treatment of complicated skin and skin structure infections caused by susceptible gram-positive bacteria in adults.

The FDA has approved an extended-release formulation of amoxicillin (Moxatag – MiddleBrook) for once-daily treatment of pharyngitis or tonsillitis caused by Streptococcus pyogenes in adults and children ≥12 years old. Approval was based on an unpublished study that found once-daily treatment with Moxatag 775 mg for 10 days non-inferior to penicillin V 250 mg four times a day for 10 days in eradication of S. pyogenes.

For decades, the drug of choice for oral treatment of streptococcal pharyngitis in adolescents and adults has been penicillin V 250 mg taken three or four times a day.1 Amoxicillin is equally effective, but penicillin is generally recommended because of its narrower spectrum. In adults, immediate-release amoxicillin is usually dosed 375-500 mg two to three times a day, but giving it in a higher dose (750-1000 mg) once a day appears to be equally effective for treatment of strep throat.2-4

Each Moxatag tablet contains 775 mg of amoxicillin divided into one immediate-release and two delayedrelease components. Compared to a similar dose of immediate-release amoxicillin suspension, absorption of amoxicillin from the new formulation is slower, resulting in a lower peak serum concentration, but the elimination half-life and amoxicillin exposure (AUC) are similar. S. pyogenes is susceptible to these serum concentrations, but they may be too low to treat other types of infections.

A 10-day supply of Moxatag is expected to cost about $100 compared to $4 for a similar course of penicillin V or immediate-release amoxicillin.5 There is no good reason to prescribe Moxatag.

1. A Bisno et al. Practice guidelines for the diagnosis and management of group A streptococcal pharyngitis. Infectious Disease Society of America. Clin Infect Dis 2002; 35:113.
2. P Shvartzman et al. Treatment of streptococcal pharyngitis with amoxycillin once a day. BMJ 1993; 306:1170.
3. HM Feder Jr. et al. Once-daily therapy for streptococcal pharyngitis with amoxicillin. Pediatrics 1999; 103:47.
4. HW Clegg et al. Treatment of streptococcal pharyngitis with once-daily compared with twice-daily amoxicillin: a noninferiority trial. Pediatr Infect Dis J 2006; 25:761.
5. Retail cost at one Walgreens pharmacy. February 27, 2009.

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Retapamulin (re-tap'-a-mue'-lin; Altabax - Glaxo SmithKline) is a topical antibiotic recently approved by the FDA for treatment of bullous and non-bullous impetigo due to Streptococcus pyogenes and methicillin-susceptible Staphylococcus aureus. It is available as a 1% ointment by prescription only.

Information about empirical treatment of bacterial infections, emerging trends in antimicrobial resistance, new drugs and new data about older drugs continue to become available. Usual pathogens and empiric treatment for some common types of infections are summarized in the text and a table listing the drugs of choice and alternatives for each pathogen begins on page 40. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Tigecycline (Tygacil - Wyeth), a derivative of minocycline, is a new intravenous (IV) antibiotic approved for treatment of complicated intra-abdominal and skin and skin-structure infections.

New drugs for bacterial infections and new information about older drugs continue to become available. Empirical treatment of some common bacterial infections is discussed in this article. A table listing the drugs of choice and alternatives for each pathogen begins on page 18. These recommendations are based on results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants. Local resistance patterns should be taken into account. Trade names are listed on page 24.

Daptomycin (Cubicin - Cubist), a cyclic lipopeptide (a new class of antibiotics), has been approved by the FDA for intravenous (IV) treatment of complicated skin and skin structure infections. It is being promoted as a once-daily bactericidal alternative to vancomycin (Vancocin, and others) for methicillin-resistant Staphylococcus aureusinfections.

New drugs for treatment of bacterial infections and new information about older drugs continue to become available. Empirical treatment of some infections is discussed and a table listing the drugs of choice and alternatives for each pathogen are contained in this article. These recommendations are based on results of susceptibility studies, clinical trials and opinions of Medical Letter consultants. Local resistance patterns should be taken into account.

Since The Medical Letter last reviewed the choice of drugs for treatment of bacterial infections, a few new drugs and some new information about older drugs have become available.