(1) That which is inhaled; a remedy given by inhalation. (2) A drug (or combination of drugs) with high vapor pressure, carried by an air current into the nasal passage, where it produces its effect. (3) A solution of a drug or combination of drugs for administration as a nebulized mist intended to reach the respiratory tree. (4) Group of products consisting of finely powdered or liquid drugs that are carried to the respiratory passages by the use of special devices such as low-pressure aerosol containers. SYN: insufflation (2).inhalation, aerosol. [see inhalation]