(Reuters) - Valeant Pharmaceuticals (>> Valeant Pharmaceuticals Intl Inc), nearly two years into Chief Executive Officer Joseph Papa's turnaround plan, on Wednesday told investors earnings and revenue would drop for one more year, before a projected return to growth in 2019.

The Canada-based drugmaker's shares fell more than 10 percent in early trading.

Papa, speaking on the company's conference call for its fourth-quarter earnings, said he still believes what he has called the "turnaround of a lifetime" is on track, despite 2018 being a trough year for the company.

"It takes some time and we have to demonstrate the performance," he said.

Valeant forecast weaker-than-expected revenue for 2018, as several of its major drugs face more competition from generics. The company's top line will also be pressured as it continues to sell off businesses to free up cash and reduce its debt burden of some $25 billion.

Valeant has already divested its Dendreon cancer treatment unit as well as several skin care brands acquired during a debt-fueled deal-making binge under former CEO Mike Pearson, reducing its debt by more than 20 percent.

Chief Financial Officer Paul Herendeen showed a chart forecasting a 4 to 6 percent compound annual growth rate for revenue between 2018 and 2021. Still, he asked analysts not to infer too much from the slide, noting that the information was not to scale.

The drugmaker's U.S.-listed shares fell to $16.27 in morning trading. The stock, which hit a peak of over $250 in 2015, has suffered under intense scrutiny into the company's drug price hikes and its unorthodox use of a specialty pharmacy to boost sales.

Valeant has sharpened its focus on more profitable products including its Bausch and Lomb eye care line, treatments for gastrointestinal diseases and its dermatological business.

But it expects new competition for its drugs to cut its revenue by nearly half a billion dollars this year.

Valeant forecast 2018 revenue of $8.10 billion to $8.30 billion. Analysts on average were expecting $8.34 billion, according to Thomson Reuters I/B/E/S.

On Wednesday, Valeant said it would pay $58 million to resolve a class action lawsuit by buyers of its acne medication Solodyn, who allege that a Valeant-owned company sought to delay the launch of cheaper, generic versions of Solodyn, in violation of antitrust laws.

Valeant reported net income of $513 million in the fourth quarter ended Dec. 31, compared to a loss of $515 million a year earlier, helped by a one-time benefit of $1.32 billion from new U.S. tax laws.

Excluding one-time items, Valeant earned 98 cents per share, edging past analysts' estimates of 97 cents.

Revenue fell 10 percent to $2.16 billion, just shy of analysts' expectations of $2.17 billion.

(Reporting by Michael Erman in New York and Manas Mishra in Bengaluru; Editing by Sai Sachin Ravikumar and David Gregorio)

By Michael Erman and Manas Mishra