Why is cromolyn sodium solution for nebulizers no longer available in the usa?

Not profitable: So few people were using it that it became unprofitable for medication manufacturers to produce or pharmacies to stock the product. Leukotriene receptor antagonists like singulair (montelukast) & accolate, while working by different mechanisms, were found to be about as effective & safe but far more convenient to use than cromolyn. They replaced cromolyn as a non-steroidal controller medication.