Updated from 8:42 a.m. EDTMerck ( MRK) missed analysts' profit forecast for the first quarter, said that sales declined from a year earlier and lowered its full-year net earnings estimate because of costs related to the pending merger with Schering-Plough ( SGP). Shares of the Whitehouse Station, N.J., drugmaker were down 6.1% at $23.69 recently. Merck, one of five components of the Dow Jones Industrial Average reporting results Tuesday, said it earned 74 cents a share in the quarter, excluding items. On average, Wall Street analysts were predicting 77 cents. After factoring in the items, Merck earned $1.46 billion, or 67 cents a share. A year earlier, the company made $3.33 billion, or $1.52 a share. The 2008 results included a $1.4 billion after-tax gain from a distribution from AstraZeneca ( AZN).