Comparison of oral and aerosol ribavirin regimens in the high risk elderly.

A comparison of different regiments of ribavirin (R), administered either orally or by aerosol, was performed in 16 elderly subjects (13 men, 3 women, mean age 63 +/- 8 years) considered to be in the "high-risk" category for complications from influenza as defined by the Centers for Disease Control. The subjects were divided into four groups. Group O-600 received 600 mg orally R every 8 hours for 48 hours followed by 200 mg every 8 hours for 72 hours for a total dose of 5.4 g (22.1 mmol). Group O-800 received 800 mg oral R every 8 hours for 24 hours followed by 400 mg every 12 hours for 96 hours for a total dose of 4.1 g (22.9 mMoles). Group A-40 received R (40 mg/ml) aerosolized through a small particle aerosol generator for 6 hours every 12 hours for 96 hours, yielding an average delivered dose of 6.2 g (25.4 mMoles) R. Group A-60 received aerosolized R (60 mg/mL) for 2 hours every 8 hours for 96 hours, yielding an average delivered dose of 4.6 g (18.8 mMoles) R. No hematologic or other laboratory abnormalities were associated with any of the regimens. Group O-800 and O-600 reached mean peak plasma R levels of 11.8 microM and 5.3 microM, respectively, after 18 hours of therapy. Subsequent administration of 20 mg R every 8 hours was sufficient to maintain a plasma R level greater than 7 microM. Among the aerosol groups, group A-40 approached steady state plasma R levels (8-10 microM) more quickly than group A-60.(ABSTRACT TRUNCATED AT 250 WORDS)