Pfizer ( PFE) Thursday reiterated its full-year EPS forecast but revised its revenue projection ahead of its second-quarter earnings release next week. The world's No. 1 drugmaker said it expects to earn $2.13 a share on revenue of $52.5 billion to $53 billion. In April, Pfizer had reiterated its full year financial guidance of about $54 billion in revenue and net earnings -- excluding special charges -- of $16.3 billion, or $2.13 a share. Analysts expect New York-based Pfizer to post net income of $15.92 billion, or $2.12 a share, on revenue of $52.86 billion for the year and net income of $3.5 billion, or 46 cents a share, on revenue of $12.29 billion for the second quarter. The company Thursday said "the revised revenue forecast reflects revisions for a number of products as well as the effect of foreign exchange fluctuations." For the first quarter, the company earned $3.98 billion -- or 52 cents, and a penny better than the consensus forecast -- on revenue of $12.49 billion. Without adjustments for discontinued operations, acquisitions and other items, Pfizer had first-quarter net income of $2.33 billion, or 31 cents a share. Despite that performance, Pfizer surprised the markets in reporting that first-quarter worldwide sales of its top-selling erectile dysfunction drug Viagra declined 12% to $416 million, while the U.S. sales component sank by 25% to $220 million. The company admitted sales were "not as well as we had hoped" but was taking several steps to fortify Viagra's market presence. Pfizer has something of a Viagra customer loyalty program. After filling six prescriptions, men can get the seventh prescription free. The program applies only to men who pay for the entire prescription out-of-pocket or for the part of the prescription not covered by insurance.