Valeant Pharmaceuticals International Inc.  reported a smaller-than-expected quarterly profit due to faltering sales of its dermatology products and irritable bowel syndrome drug, and the company cut its full-year profit and revenue forecasts.

Valeant's U.S.-listed shares fell more than 10 percent in premarket trading on Tuesday. Up to Monday's close of $19.13, the stock had fallen 81 percent this year.

The Laval, Quebec-based company said it now expected total revenue of $9.55 billion-$9.65 billion for the year, down from its previous forecast of $9.9 billion-$10.1 billion.

Adjusted earnings are now forecast to be $5.30-$5.50 per share, compared with the previous forecast of $6.60-$7.00.

The net loss attributable to Valeant was $1.22 billion, or $3.49 per share, in the quarter ended Sept. 30, compared with a profit of $49.5 million, or 14 cents per share, a year earlier.

The company took a goodwill impairment charge of $1.05 billion in the latest quarter, reflecting the lower fair value of some U.S. businesses, mainly its Salix division, which makes irritable bowel syndrome drug Xifaxan.

Valeant, which has debt of more than $30 billion, said last week it was in talks with third parties to sell the business and some other assets.

Excluding items, the company earned $1.55 per share, well below analysts' average estimate of $1.73, according to Thomson Reuters I/B/E/S.

Revenue fell 11 percent to $2.48 billion, compared with the average estimate of $2.49 billion.

Sales in Valeant's Branded Rx unit, which contributed 34 percent to the total revenue, fell to $847 million from $1.1 billion in the quarter.

The unit includes the dermatology business and Salix, which Valeant bought for $14.5 billion last year.

Valeant has been criticized for its pricing and business practices and is being probed by U.S. regulators and Congress.