** Canadian drugmaker's U.S.-listed shares down about 10 pct at $160 premarket
** Valeant said late on Wednesday it has been subpoenaed by U.S. prosecutors seeking information on its pricing decisions, drug distribution and patient assistance programs
** Valeant, along with Turing Pharmaceuticals, has come under fire after Hillary Clinton last month underscored the prevalence of pharmaceutical "price gouging"
** CEO Pearson's pricing strategy has been likened to that of Martin Shkreli, the controversial CEO of Turing, after the small company raised the cost of an old anti-infective drug by more than 5,000 pct
** Valeant raised prices on Isuprel by three times and on Nitropress by more than six times after buying the heart drugs in February.
** Up to Wednesday's close, stock had fallen 18 pct since Sept. 22 when Clinton proposed a $250 monthly cap on out-of-pocket prescription drug costs.