WOODCLIFF LAKE, N.J. Par Pharmaceutical has begun shipments of a generic treatment for asthma, the drug maker said Monday.

Par announced that it started shipping zafirlukast tablets in the 10-mg and 20-mg strengths. The drug is a generic version of AstraZeneca’s Accolate.

Accolate has sales of $50 million in the United States per year, according to IMS Health.