[Prolonged preventive antibiotic therapy of chronic bronchitis].
D000328:Adult; D001991:Bronchitis / Q000517:prevention & control*; D002908:Chronic Disease; D002986:Clinical Trials as Topic; D006801:Humans; D008297:Male; D008690:Methacycline / Q000008:administration & dosage*; D008875:Middle Aged; D009787:Occupational Medicine; D010919:Placebos
D010919:Placebos; D008690:Methacycline
Trattamento antibiotico profilattico protratto delle bronchiti croniche.