The U.S. Patent and Trademark Office yesterday extended patents for six pharmaceutical products and two medical devices, marking the first use of a 1984 law that provided longer patent protection for brand-name drugs.

Commissioner Donald J. Quigg signed certificates lengthening the protection on the drugs and devices under the law, which allowed both for more rapid approval of generic versions of some pharmaceutical products and expanded patent protection for others.

The law allows drug manufacturers extensions of patents to make up for marketing time lost after a patent is granted because of regulatory review by the Food and Drug Administration.

"Restoration of patent terms preserves the vitality of the patent system as a means of encouraging innovation and scientific advancement in a way that also reflects the obligation of federal agencies to protect the American people from products that are unsafe or ineffective," Quigg said.

The patents that received extensions were for Ridaura, an arthritis medication, owned by SmithKline Beckman and extended two years to Jan. 2, 1992; Sectral, a treatment of arrhythmia and hypertension, owned by May and Baker Ltd. and extended two years to Dec. 17, 1993; Seldane, an antihistamine, owned by Merrell Dow and extended two years to April 15, 1994; Tornolate, a treatment for bronchitis, owned by Sterling Drug and extended two years to Feb. 6, 1998; Promit, a sterile aqueous solution, owned by Pharmacia Aktiebolag of Sweden and extended 468 days until 1999; and Tonocard antiarrhythmic tablets, owned by Astra Pharaceutical Products and extended 342 days until late 1997.

Also extended, for 90 days, was the patent on New Jersey Knee, a knee implant, owned by Biomedical Engineering Corp. that would have expired Jan. 12, 1999, and, for 382 days, the patent on the Beta 3000 cancer-scanning device.

Fonar Corp., which owns the patent on the magnetic-resonance scanner, has sued Johnson & Johnson, claiming that a former subsidiary infringed the patent by selling a competing system. A U.S. District Court jury in Boston agreed, but the decision is being appealed.

"Financially the patent extension could be very helpful to Fonar," said Roger Hampton, director of communications for the company. If the appeals court upholds the jury's decision, Fonar will be able to collect damages from Johnson & Johnson and other companies that it claims are using its patented technology.