Eli Lilly and Co. unveiled a better-than-expected 2013 earnings forecast Friday, in part because the pharmaceutical company expects growth from several established drugs to help make up for revenue lost to generic competition.

The Indianapolis drug developer saw sales for its all-time best-selling drug, the antipsychotics Zyprexa, crater in 2012 after it lost U.S. patent protection. Lilly will take another hit next December when it loses patent protection for its current top seller, the antidepressant Cymbalta.

But company executives told analysts Friday morning they still expect Cymbalta and another product that loses patent protection in 2013, the insulin Humalog, to help drive revenue growth along with products like the cancer treatment Alimta and the erectile dysfunction drug Cialis.

Lilly also expects more growth from Japan, developing countries and its animal health business.

All told, the drugmaker forecast 2013 adjusted earnings of between $3.75 and $3.90 per share on a range of $22.6 billion to $23.4 billion in revenue.

That topped analyst expectations, on average, for earnings of $3.72, according to FactSet. Analysts also expected $22.87 billion in revenue.

Company shares climbed $1.86, or 3.7 percent, to $51.58 in midday trading Friday, while broader indexes rose less than 1 percent.

Lilly said it expects operating expenses will be flat or drop slightly compared with 2012, and that was slightly better than what Edward Jones analyst Judson Clark expected.

He called Lilly's 2013 forecast "a pleasant surprise," but he also noted that plenty of long-term concerns remain. Lilly won't feel the brunt of the Cymbalta patent loss until 2014, and Clark expects the company's earnings to shrink then. What remains to be seen, he said, is whether the drugmaker is willing to preserve its dividend and cut expenses enough to tame that loss.

"We think the real question marks are in 2014," he said.

Lilly also expects to counter the patent expirations by developing new drugs, and the company said Friday it has 13 experimental drugs in late-stage testing, the last phase before a company seeks regulatory approval.

Lilly reiterated on Friday that it expects at least $3 billion in net income and revenue of at least $20 billion through 2014. It also expects to keep paying shareholders a dividend and to complete a $1.5 billion share repurchase program this year.

Zyprexa once brought in more than $5 billion in annual revenue for Lilly, but its sales sank 66 percent through the first nine months of 2012 after generic competition entered the market. The company also expects revenue from Cymbalta, which topped $4 billion in 2011, to start falling in this year's fourth quarter.

Humalog, Lilly's best-selling insulin, brought in about $1.4 billion in total revenue in 2011, but that product may take less of a sales hit after it loses U.S. patent protection in May because it's a biologic drug made from living cells instead of a chemical formula. Those are harder for generic drugmakers to replicate.

The company cannot expect to replace blockbuster drug revenue with another round of blockbusters, said WBB Securities analyst Steve Brozak. He said Lilly's success will depend on a combination of drug development, partnerships with other companies and acquisitions that help stoke its product pipeline.

But that approach will be difficult because other drugmakers also are facing patent expirations and will be competing with Lilly on those deals.

"If (Lilly executives) think that business as usual applies, their shareholders are going to vote with their sell orders," he said.

The company reports fourth-quarter and 2012 results Jan. 29.