PITTSBURGH (AP) – The fathers of two people killed in a western Pennsylvania murder-suicide say a smoking cessation drug is to blame.

Thirty-four-year-old Sean Wain fatally shot his 33-year-old wife, Natalie, before shooting himself in Economy, in May 2009. A lawsuit filed by their fathers on behalf of the couple’s four surviving children says Sean Wain’s hostility and rage was prompted by the drug Chantix, marketed by Pfizer Inc.

The drug company did not immediately comment on the lawsuit filed Monday in U.S. District Court in Pittsburgh. But a Web site for the drug warns it can cause “hostility, agitation, depressed mood, suicidal thoughts or actions” in some people.

The lawsuit says New York-based Pfizer didn’t sufficiently warn consumers until after the murder-suicide, even though those side effects were allegedly revealed during clinical trials of the drug.

The Associated Press