Shoppers Drug Mart could face a lawsuit after the company reduced the value of the Optimum card points on July 1.

MONTREAL – Canada’s largest pharmacy chain could face a class-action lawsuit over the value of its Optimum card points.

Customer Pierre Gaumond has asked a judge to approve the suit, which says Shoppers Drug Mart was wrong to reduce the value of the Optimum points on July 1.

Gaumond says the move violates the chain’s contract with 9.7 million cardholders across Canada. The class-action request was filed Wednesday in Quebec Superior Court in Montreal.

Optimum cards allow Shoppers clients to amass points that can be redeemed later for an array of items.

It now takes 8,000 Optimum points to cash in a $10 rebate, up from 7,000 points just last month, the suit claims.

“The retroactive modification of an essential element of a contract of this type is abusive and illegal,” said lawyer Marie-Anais Sauve of the law firm Sylvestre Fafard Painchaud, which is spearheading the suit.

Shoppers was not immediately available for comment.

The litigants want a judge to force the drugstore chain to revert to the old formula for calculating Optimum points.

It could take up to a year for the judge to decide whether to approve the suit, says Sauve.

Shoppers Drug Mart, known as Pharmaprix in Quebec, has nearly 1,200 outlets across Canada.