Johnson & Johnson is preparing a push to extract concessions from Schering-Plough in exchange for allowing Merck’s planned $46bn takeover of Schering to move forward without a messier fight, dealmakers say.

J&J and Schering are partners in marketing two lucrative arthritis drugs, which Schering has the rights to sell outside the US. Merck and Schering say their merger is structured in a way that will not terminate that partnership agreement, which could give J&J a chance to control the drugs outright.