Cromolyn sodium acts by

• A. Metabolizing histamine
• B. Destroying histamine
• C. Releasing histamine
• D. Preventing the release of histamine

Answer: (D)

Cromolyn sodium works by stabilizing mast cells and preventing their degranulation, which stops histamine and other mediators from being released when an allergen is encountered. By keeping the mast cell membranes intact, it prevents the cascade of inflammatory signals that would normally lead to symptoms such as itching, swelling, and bronchoconstriction. It doesn’t metabolize or destroy histamine, nor does it cause histamine release. It’s used prophylactically to reduce symptoms, not to treat an active histamine surge.