Why are so many asthma drugs taken via inhaler?
Medications taken orally almost always have a much higher systemic concentration (concentration in your entire body) than inhaled medications. So if the side effects are due to systemic concentrations, then an inhaled drug is less likely to have these side effects, or may have them much less severely. The idea behind an inhaler is that the full dose is delivered to the lungs, where it is immediately absorbed by the lung tissue, and starts to take effect locally. Excess drug may be absorbed by the bloodstream and delivered to the rest of your body, but this amount tends to be minimal. So your lungs receive an immediate, high concentration of the drug, and the rest of your body receives very little. If you take the drug orally in tablet or capsule form, then you need a much higher dose. The reason is that for the same amount of drug to reach the lungs through the bloodstream, you need the same concentration of drug in the rest of your body. For example, most people take one or two puffs
