Allergan (NYSE:AGN) asked Salix Pharmaceuticals (NSDQ:SLXP) about a potential merger as it looks to stymie a $53 billion hostile takeover by Valeant Pharmaceuticals (NYSE:VRX, TSE:VRX) and William Ackman’s Pershing Square Capital Management hedge fund, the Wall Street Journal reported.

A deal with Salix or another possible suitor could happen as soon as next month, according to the newspaper. A union with Salix could make the resulting entity too expensive and complex for the Valeant/Pershing alliance to acquire, according to "people familiar with the matter," the Journal reported.

The picture is complicated by Salix’s plan to merge with Italy’s Cosmo Pharmaceuticals, a $2.6 billion tax inversion deal that would shift Salix’s home base from North Carolina to Ireland.

News of Allergan’s approach to Salix sent AGN stock up 4.0% to a $161.82-per-share close yesterday; shares were trading at $161.81 apiece as of about 1:30 p.m. Eastern today, down -0.01%. SLXP shares jumped 15.5% to a $160.80 close, but were down -1.7% to $158.00 today.

Salix said yesterday that the U.S. Federal Trade Commission granted early termination of the waiting period for antitrust review of the Cosmo deal, according to the newspaper.