What is the primary route of administration for ribavirin when used for inhalation?

Ribavirin is primarily administered via inhalation when used for specific respiratory viral infections, particularly in cases such as respiratory syncytial virus (RSV) in infants and young children. Inhalation delivery allows the medication to reach the lungs directly, maximizing its therapeutic effect at the site of infection. This method of administration is crucial because it provides high local concentrations of the drug in the respiratory tract while minimizing systemic exposure and potential side effects that could occur with other routes.

Other options, such as intravenous administration or oral intake, do not provide the targeted delivery that inhalation offers for respiratory infections. Intravenous use is typically reserved for more severe cases needing rapid systemic effects, while oral administration can lead to less effective concentrations at the site of action, given the drug's need to traverse the gastrointestinal system before reaching the bloodstream. Topical application is not suitable for respiratory issues, as ribavirin's effectiveness is directly related to its presence in the respiratory tract. Thus, inhalation is indeed the most effective route for delivering ribavirin for respiratory treatment.