Pfizer, which manufactures brands including Advil, Centrum, ChapStick and Robitussin, is considering whether to sell its portfolio of over-the-counter (OTC) remedies to focus on its prescription medicine business. Pfizer’s consumer brands business generated $3.4 billion in sales last year. The company’s prescription medicines, which include Lipitor and Viagra, generated a profit of $3.07 billion in the second quarter on sales of $12.9 billion.