Minocycline in the antibiotic regimen of cystic fibrosis patients: weight gain and clinical improvement.

Minocycline hydrochloride was given to 100 patients with cystic fibrosis of the pancreas for periods of 3 months over a broad-spectrum antibiotic drug rotation which lasted 2 years. Increased weight gain and some clinical improvement was seen during treatment with minocycline. Those patients with severe disease gained more weight than those with mild or moderate disease, and males gained more than females. When minocycline hydrochloride was not the drug in use, patients lost weight and their health declined.