The general hypothesis is that delayed antibiotic treatment strategies present similar effectiveness, when compared with non-prescription of antibiotics or the prescription of antibiotics, in the non-complicated acute respiratory tract infections.

The aim of the PDA study is to assess the efficacy and safety of different delayed antibiotic prescribing strategies, compared to direct antibiotic treatment and no antibiotic treatment, for the treatment of non-complicated acute respiratory infections, in terms of symptoms duration and severity. Moreover, antibiotic consumption, patient satisfaction, efficacy perception and number of medical visits will be also assessed for each therapeutic strategy.

The PDA is a multicentric study, parallel, randomised controlled trial to compare four antibiotic prescribing strategies in the non-complicated acute respiratory tract infections. The trial will include acute pharyngitis and/or acute tonsillitis, rhinosinusitis, acute bronchitis and acute exacerbation of chronic obstructive pulmonary disease with (mild to moderate) in adults. The expected number of patients to be included in this trial is 600. Therapeutic strategies include: direct antibiotic treatment, no antibiotic treatment, and two delayed antibiotic prescribing strategies (prescription given to patient with advice to use a course of antibiotics if needed in case of worsening of symptoms or not improving, and prescription left at the reception of the primary care center 3 days after the first medical visit). Follow-up period will be one month. The primary outcome will be symptom duration and severity. Other outcomes included will be use of antibiotics, patient satisfaction, perception of antibiotic efficacy, complications, and number of medical visits.

General Inclusion Criteria:

In this study can be enrolled adult patients with non-complicated acute respiratory tract infections, including pharyngitis and/or tonsillitis, rhinosinusitis, acute bronchitis and exacerbations of chronic obstructive pulmonary disease mild to moderate. The doctors include patients with these infections if they have reasonable doubts if the patients should treat with antibiotics

General Exclusion Criteria:

• Patients have participated in the PDA previously.
• Patients are severely affected or patients has been felt severely affected for a week (all time)
• Patients with symptoms and signs suggestive of serious illness or severely affected and/or complications (particularly pneumonia, mastoiditis, peritonsillar abscess, peritonsillar cellulitis, intraorbital or intracranial complications).
• Patients at high risk of serious complications due to prior comorbidity. This includes significant heart disease, lung, kidney, liver or neuromuscular, immunosuppression, cystic fibrosis.
• If the patient is over 65 years with acute cough and two or more of the following criteria or more than 80 years with acute cough and one or more of the following criteria:
• Hospitalization in the previous year
• Diabetes Type I or II
• History of heart failure
• Current use of oral corticosteroids.