A putative class action charges Wyeth Inc. with violating antitrust and consumer protection laws by impeding the introduction of a generic version of its antidepressant Effexor XR.

The suit, filed Oct. 21 on behalf of indirect purchasers of Effexor XR, alleges Wyeth fraudulently obtained three patents on Effexor XR, then sued 13 generic drug makers that sought approval to produce the drug, so it could postpone the rollout of their versions by two years.