PITTSBURGH — The Food and Drug Administration has approved a generic treatment for bronchospasm made by Mylan, the drug maker said Monday.

Mylan announced the approval of levalbuterol inhalation solution in the 0.31 mg/3 mL, 0.63 mg/3 mL and 1.25 mg/3 mL strengths. The company has begun shipping the product.

The drug is a generic version of Sunovion's Xopenex inhalation solution, which is used to treat bronchospasm in patients ages 6 years and older with reversible obstructive airway disease.

Various versions of the drug had sales of $438.8 million in 2012, according to IMS Health.