Groups collaborate on pneumonia guidelines

February 19, 2007

The Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) recently released guidelines for the diagnosis and treatment of community-acquired pneumonia (CAP). These guidelines are the first collaborative effort between these two organizations on CAP guidelines. IDSA last updated its CAP guidelines in 2003.

Lionel Mandell, M.D., FRCP(C), FRCP (Lond), a professor of medicine at McMaster University in Hamilton, Ontario, said that one of the main themes of the guidelines is minimizing the "misuse and abuse of antibiotics."

Michael Klepser, Pharm.D., a professor of pharmacy at Ferris State University in Kalamazoo, Mich., concurred, and cautioned that clinicians must understand that a miracle antibiotic is not going to be released every year. Klepser, who is also president of the Society of Infectious Diseases Pharmacists, advised clinicians to use available antibiotics in an optimal yet cost-effective way. He said they should try to maximize clinical outcomes and minimize the potential for resistance and adverse drug reactions.

The committee divided those treated for CAP as outpatients into three groups, said Mandell. The first group was previously healthy and had not received antimicrobials in the three months prior; the second group either had comorbidities such as cardiovascular, pulmonary, or renal disease, or had received antimicrobials in the past three months; and the third group lived in an area of the country with a high prevalence of "high-level" macrolide-resistant Streptococcus pneumoniae.

The authors recommended that those in the first group be treated with either a macrolide (clarithromycin 500 mg taken twice daily or azithromycin 500 mg taken one time and then 250 mg taken once daily thereafter) or doxycycline (100 mg taken twice daily).

For those in the second group who had received antimicrobials within the past three months, the committee recommended choosing an antimicrobial from a different drug class. For example, those who received a macrolide should receive a respiratory fluoroquinolone, moxifloxacin (Avelox, Bayer) 400 mg taken once daily, gemifloxacin (Factive, Oscient) 320 mg taken once daily, or levofloxacin (Levaquin, Ortho-McNeil) 750 mg taken once daily.

Those who received a respiratory fluoroquinolone should receive a beta-lactam antibiotic and a macrolide. In terms of beta-lactam antibiotics, the authors recommended high-dose amoxicillin (1 gm taken three times daily) or amoxicillin/ clavulanate (2 gm taken twice daily). Suggested alternatives include ceftriaxone (1 gm to 2 gm administered intravenously once daily), or cefpodoxime or cefuroxime (500 mg taken twice daily). The committee recommended doxycycline as an alternative to the macrolide. Mandell said that for members of the third group, who live in regions where macrolide resistance is an issue, alternatives such as the respiratory fluoroquinolones should be considered.

One change in the treatment guidelines is the recommendation that antimicrobial therapy be initiated as soon as possible. The previous guidelines recommended a window for initiation of antibiotic therapy of four hours. In addition, Mandell said, the duration of therapy has been shortened to a minimum of five days. However, patients must be afebrile for 48 to 72 hours and have no signs of clinical instability. Mandell said that a longer duration of treatment is necessary if complications due to extrapulmonary infection such as endocarditis or meningitis are present, or if bacteremia sets in, particularly Staphylococcus aureus, S. pneumoniae or Pseudomonas aeruginosa.

Pharmacists can help reevaluate patients periodically, discontining antimicrobial therapy when appropriate. The guidelines are on the IDSA Web site at http:// http://www.idsociety.org/, and will be published as a supplement to the March 1 issue of Clinical Infectious Diseases.

THE AUTHOR is a clinical writer based in New Jersey.