Estimating the dosage of ribavirin aerosol according to age and other variables.

We describe a method for estimating the dosage of aerosolized ribavirin according to age. The calculations were determined by using a computer model of particle deposition, and corrections are described for sex, body weight, fever, and tracheal intubation. Respiratory tract deposition in infants, after they inhaled an aerosol containing 200 micrograms of ribavirin/L, was 1.8 mg/kg per hour; in adults the deposition was 0.9 mg/kg per hour. Adolescent females and older women have less (7%/kg) respiratory tract deposition than do males. Fever will increase deposition about 9%/degree Centigrade (5%/degree Fahrenheit) for each degree of increase above normal temperature. Tracheal intubation will deliver relatively more drug to the lung and no drug to the nasopharynx. Our report shows the regional and total deposition of inhaled ribavirin aerosol in the respiratory tracts of persons in different age-groups from three months to 25 y.