WASHINGTON -- There's a twist to the agreement that settles price-fixing charges against the Nintendo video-game company: Victimized consumers must buy another Nintendo product in order to be compensated.

The settlement requires Nintendo of America Inc. to offer a $5 coupon to consumers who may have paid unnecessarily high prices for the company's immensely popular video-game consoles.

As many as 400,000 Maryland consumers will be eligible to receive coupons, which can be used when purchasing Nintendo games, said state Attorney General J. Joseph Curran Jr.

Curran and other officials defended the coupon program as the most practical way to provide compensation.

They said consumers who bought consoles probably would be in the market anyway for more games and, hence, would save. And they said the alternative, a direct payment by check, would have resulted in payments of less than $5 because of the costs involved.

Curran emphasized the importance of the settlement in getting Nintendo, the video game industry giant, to stop its alleged practices. And other companies will think twice before doing the same thing, he said.

State and Federal Trade Commission officials said the joint nature of the Nintendo investigation was unprecedented and would be continued with other cases.

From June 1988 through December 1990 Nintendo allegedly forced retailers to sell the game-playing console for the suggested retail price of $99.95. Retailers who sought to sell it for less were threatened with a supply cutoff, state and federal officials saidyesterday in announcing the settlement.