Your doctor has just prescribed an inhaled steroid-based drug to treat your asthma. What do you predict about its mechanism of action? A. The drug binds to receptors on the cell membrane, activating a second messenger pathway that phosphorylates a set of target proteins. B. The drug binds to an extracellular receptor, then crosses the cell membrane where it directly phosphorylates a set of target proteins. C. The drug crosses cell membranes, binds to an intracellular receptor, enters the nucleus and regulates gene transcription. D. The drug acts in the bloodstream to bind and sequester antibodies and thereby reduce inflammation in the lungs.

The drugs is taken inside the body by many means such as intravenously, orally et cetera. The mechanism of action of drug can be defined as the mode by which the drugs gets inside the body.

In case of asthma the drugs crosses cell membrane, and binds to the receptor that is present inside the cell. Then it reaches the nucleus of the cell and helps in regulation of gene transcription. This is how the drug for asthma works inside the body.