(Adds details, updates prices)
* TSX down 86.83 points, or 0.63 percent, to 13,705.05
* Nine of the TSX's 10 main groups fall
TORONTO, Oct 30 (Reuters) - Canada's main stock index fell on Friday, weighed down by Valeant Pharmaceuticals International Inc after it cut ties with a beleaguered pharmacy business, and by retreats in the heavyweight energy and financial sectors.
The most influential single weight on the index was Valeant, which fell 7.0 percent to C$137.91 after it said it will sever ties with Philidor Rx Services in the wake of criticism over the relationship between the two closely associated companies.
At 10:00 a.m. ET (1400 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 86.83 points, or 0.63 percent, to 13,705.05. Nine of its 10 main groups fell.
The index is on track for a 1.8 percent decline on the week and a 3 percent gain for October.
The overall energy group retreated 0.4 percent, with Husky Energy Inc down 7.5 percent to C$18.75 after swinging to a quarterly loss on a writedown and impairment charge.
U.S. crude prices were down 0.8 percent to $45.7 a barrel, while Brent lost 0.1 percent to $48.76.
Barrick Gold advanced 1.2 percent to C$10.43. The world's biggest gold producer said on Thursday it will increase its focus on productivity gains in 2016.
But the materials group, which includes miners, fell 1 percent, with fertilizer company Potash Corp down 3 percent at C$26.50 a day after cutting its output and earnings forecast.
Gold futures fell 0.4 percent to $1,142.8 an ounce, while copper prices were unchanged at $5,131 a tonne.
Financials retreated 0.7 percent, with Royal Bank of Canada down 1.3 percent to C$75.50.
Reporting by Alastair Sharp; Editing by Dan Grebler