Final answer:
Cromolyn sodium inhibits the release of mediators from mast cells after exposure to an antigen, preventing the inflammatory response that leads to asthma symptoms.
Step-by-step explanation:
Cromolyn sodium is prescribed for the client with allergic asthma because it inhibits the release of mediators from mast cells after exposure to an antigen.
This action helps to prevent the inflammatory response that leads to the constriction of the airways and other symptoms of allergic asthma.
By inhibiting the release of mediators, cromolyn sodium helps to keep the airways open and reduce the frequency and severity of asthma attacks.