Concentrations of antimicrobial agents in middle ear fluid, saliva and tears.

Antibiotics concentrations in middle ear fluid (MEF), saliva and tears were measured in children with persistent middle ear effusions undergoing tympanostomy tube placement. In 31 children given cefaclor, specimens of serum, saliva and MEF were collected at 0.5, 1, 2, 3 or 5 h after a dose. Another group of 37 children were randomized to receive a single dose of penicillin V, amoxicillin, ampicillin, erythromycin estolate, erythromycin ethylsuccinate, trimethoprim-sulfamethoxazole or cefaclor. Concentrations of antibiotics in saliva and tears bore no consistent relationship to those in MEF. Mean concentrations of all drugs in MEF were several-fold greater than the usual minimal inhibitory concentrations (MIC) of pneumococci, but only with trimethoprim and cefaclor were they greater than in usual MIC's for Haemophilus influenzae. Concentrations of antibiotics in MEF in persistent effusions were comparable to those previously reported in acute purulent effusions.