Pfizer Inc. (PFE) on Tuesday reaffirmed it expects 2004 earnings to be over 20 percent higher than last year, but warned that results in 2005 and 2006 will be hurt by patent expirations on over a half-dozen of its best-selling medicines.

The world's largest drugmaker told industry analysts at a meeting at its research facilities in Groton, Conn. that it expects earnings in 2004 of $2.12 to $2.14 per share, excluding special items. Including special items, it projected earnings of $1.58 to $1.60 per share.

Pfizer in October said it was too early to make a forecast for 2005, but said results will likely be hurt by generic competition for its anti-fungal drug Diflucan (search), epilepsy treatment Neurontin, antibiotic Zithromax (search) and hypertension treatment Accupril.

The four drugs have collective annual sales of over $5 billion, revenue which is expected to plunge once cheaper generics reach drugstores.

Wall Street expects Pfizer's earnings growth to decline to the 9 percent range in 2005 and then rise only about 6 percent in 2006 due to more patent lapses.

Pfizer has warned it could lose U.S. marketing exclusivity in 2006 on anti-depressant Zoloft (search), with patents lapsing in 2007 on allergy drug Zyrtec and hypertension treatment Norvasc. Those three blockbusters had combined sales last year of almost $9 billion.