Bayer AG (BAYN) agreed to acquire Merck & Co.’s consumer unit for $14.2 billion, solidifying its position near the top of the market for over-the-counter health products. The two companies also will collaborate on the development and marketing of a class of drugs that includes Bayer’s Adempas, which is approved to treat pulmonary arterial hypertension, Merck and Bayer said in a statement today. Merck will pay Bayer $1 billion for the collaboration, with additional payments possible if sales goals are met.