Why is cromolyn sodium solution for nebulizers no longer used?

Not available. This medication is no longer on the market, but i never heard a reason why. Most often, these are business decisions - even if a medication is effective, it will be discontinued if it doesn't generate enough profit for the manufacturer. With cromolyn, however, there probably wasn't enough bang for the buck; inhaled steroids are vastly more effective, and cromolyn was quite expensive.