NEW YORK (CNN/Money) - Wyeth Corp. slashed its 2002 earnings guidance Friday, citing sales shortfalls for several of its products.

Excluding items, the drugmaker now expects to earn $2.22-$2.32 a share for the full year, sharply lower than Wall Street forecasts of $2.49 a share, according to earnings tracker First Call. The company also warned that third-quarter earnings will be "substantially below" a year ago, but that fourth-quarter results should come in higher than the year-earlier period.

Analysts are predicting 69 cents a share for the third quarter and 70 cents for the fourth, according to First Call.

Wyeth (WYE: down $6.69 to $31.76, Research, Estimates) shares tumbled more than 15 percent at midday Friday.

Wyeth blamed the lower guidance on poor sales of key drugs such as Premarin hormone treatment for women, vaccines Prevnar and FluShield, and ProHeart 6 for animal health care.

The company also cited a struggling consumer business as retailers reduce inventory amid sluggish cough and cold treatment sales, thus cutting into profit.

Wyeth also said it will add $1.4 billion to its reserves for litigation related to recalled diet drug fen-phen, suspected of causing heart problems.

The company said it expects to take charges in the quarter related to the fen-phen litigation, and will record a gain related to the merger of biotechnology companies Amgen Inc. and Immunex Corp. Wyeth owned a large stake in Immunex, and now owns part of Amgen.

Wyeth's shares fell 40 percent in July after a study showed women taking its Prempro product -- which contains estrogen in combination with a synthetic female hormone called progestin -- slightly increased the risk of breast cancer, stroke and heart disease after five years of use. Another study raised safety concerns about its lucrative Premarin hormone replacement therapy.  

-- Reuters contributed to this report.