No Antibiotics Necessary for Lower Respiratory Tract Infection


Am Fam Physician. 2005 Oct 1;72(7):1328-1330.

Clinical Question: What is the optimal management strategy for acute uncomplicated lower respiratory tract infection?

Setting: Outpatient (primary care)

Study Design: Randomized controlled trial (single-blinded)

Allocation: Concealed

Synopsis: Investigators enrolled 807 adults and children who presented to their primary care physician with cough and at least one other symptom referable to the lower respiratory tract (e.g., colored sputum, chest pain, dyspnea, wheezing). Patients with asthma, other chronic lung diseases, or suspected pneumonia were excluded.

Participants were assigned randomly in a factorial design to one of six groups. One half of the patients received an educational leaflet whereas the rest did not; all patients were then placed in one of three antibiotic groups (i.e., immediate antibiotics, no offer of antibiotics, or delayed antibiotic). Antibiotic treatment included amoxicillin in a dosage of 250 mg three times daily or erythromycin in a dosage of 250 mg four times daily. The delayed antibiotic prescription could be obtained from the medical office receptionist up to 14 days later without further physician contact.

In this study, participants were similar to patients with acute bronchitis seen in primary care; two in three patients reported fever and more than 40 percent reported production of colored sputum. Patients who were not blinded to treatment group assignment self-reported symptoms for three weeks. Follow-up occurred for 70 percent of participants at three weeks.

Using intention-to-treat analysis, there was no significant difference in the duration or severity of cough or other symptoms between patients receiving or not receiving antibiotics. The duration of “moderately bad symptoms” was shorter in the immediate antibiotic group, but only by one day. Cough lasted an average of 12 days regardless of treatment; 25 percent of patients reported a cough lasting more than 17 days after physician consultation (which is usually seven to 10 days after the cough began). Children and adults with colored sputum did not benefit more than other groups, and older patients were less likely to benefit from antibiotics.

Compared with the immediate antibiotic group, fewer patients in the delayed and control groups used antibiotics (96 versus 20 and 16 percent, respectively). The leaflet had no effect on any outcomes. Although slightly fewer patients in the delayed and control groups were satisfied, more than 75 percent of patients were satisfied with not receiving an immediate prescription for an antibiotic. The study was 80 percent powered to detect an 11 percent difference in reconsultation rates.

Bottom Line: After patients with chronic lung disease or clinically suspected pneumonia are excluded, antibiotics provide little or no benefit for patients with cough and lower respiratory tract symptoms, including patients who have fever and green sputum. Regardless of treatment method, cough will last about three weeks in the majority of patients and for at least one month in 25 percent of patients. Those who are given an immediate prescription for an antibiotic are more likely to expect antibiotics in the future. Providing a verbal explanation about the expected course and potential complications of cough during the consultation is most likely to ensure optimal patient satisfaction. (Level of Evidence: 2b)

Study Reference:

Little P, et al. Information leaflet and antibiotic prescribing strategies for acute lower respiratory tract infection: a randomized controlled trial. JAMA. June 22, 2005;293:3029–35.

Used with permission from Slawson D. No antibiotics necessary for lower respiratory infection. Accessed online July 25, 2005, at: http://www.InfoPOEMs.com.



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